Year Long 5:2 Intermittent Fasting Study Reports It's No Better Or Worse Than A Horribly Restrictive Diet

I started out planning to write about a different paper - a one year post intervention followup of people who had completed a prior year of being randomly assigned to 5:2 style intermittent fasting (IF) (2 days a week consuming 400-600 calories) vs. continuous energy restriction (typical of eating less daily) which showed that there was no difference between the two, but when I read it I realized the story was in the initial intervention, not the follow up.

The initial intervention involved randomly assigning 332 people to one of 3 dietary interventions:  Continuous (daily) energy restriction (CER), week-on, week-off energy restriction, and a 5:2 intermittent fasting pattern involving 5 days of habitual intake and 2 very low energy diet days each week.

Of the only 146 completers, no differences were found between the diets in terms of weight loss, adherence, change in lipids, or fasting glucose.

And most of that is consistent with other studies of 5:2 IF which have found that it's no better or worse than any other approach when it comes to weight loss and biochemical changes. But what's not consistent is adherence being the same, wherein other studies tend to see more people quitting IF.

Digging the tiniest bit deeper into this two things stand out. Adherence was abysmal for both CER (49% drop out rate) and IF (58% drop out rate). But what was different here was what was involved in the CER arm. Women randomized to the CER arm were aimed at consuming only 1,000 calories daily for a year, while men were aimed at only 1,200 calories daily. That's a life-suckingly low number of calories for anyone to be aimed at and honestly it surprises me that researchers (and peer reviewers) would think that degree of continuous restriction would be worthy of study.

All this to say, that people were just as likely to report adherence to a misery inducing 1,000-1,200 calorie per day diet as they were to a 5:2 IF approach does not reflect well on the enjoyability (and consequently the broad applicability) of 5:2 style diets.

And for the inevitable trolls, I'm not knocking 5:2 IF. If you love it, terrific! Don't stop! But don't anyone expect it's a panacea for all comers.

How Much Do You Like Your Diet? Given Adherence Likely Dependent On Enjoyment, Our Recent Paper Set Out To Quantify That

Back in 2012, I wondered aloud about creating a scoring system for dietary enjoyment. I blogged about it a few times here and there, and happily, a wonderful team of researchers in New Zealand took notice. Now, thanks to the hard work of Michelle Jospe, along with Jillian Haszsard, and Rachel Taylor, the first step towards its formal use has been taken.

Our paper, A tool for assessing the satisfaction of a diet: Development and preliminary validation of the Diet Satisfaction Score, was published late last year and it details our Diet Satisfaction Score's preliminary reliability and validity.

With the help of the 1,604 people (spanning 24 different countries!) who answered our survey questions, as well as 6 diverse experts (thanks to Melanie Dubyk, Kevin Hall, Scott Kahan, Silke Morrison, Marion Nestle, Sherry Pagoto, Arya Sharma and Ethan Weiss), we arrived on the following questions geared to address various aspects of dietary adherence and satisfaction

The simplest way to think of the Diet Satisfaction Score's use is the higher the overall score (each question is answered on a 5 point Likert scale and the final DSS score is calculated by way of taking the mean of all available items yielding a total score between 1 and 5), the greater an individual's satisfaction/enjoyment of that diet is. The hypothesis then would be higher scores correlating with better adherence and consequently better/sustained weight loss.

And that's what our preliminary findings suggest whereby each 1-point higher Diet Satisfaction Score correlated with a 1.7 week longer diet duration. It was also found that compared with those who had abandoned their diets, those maintaining them reported larger losses.

The value of a simple and quick score like this to individuals would be as a means to assess how much (or how little) they were enjoying their diets taking into account more than just whether they like the foods they're eating, but also the impact their chosen diet might be having on related aspects of life (socializing, time, cost, etc.). Those evaluating their new diets and finding their scores low, might explore means to tweak their diets, or to try new ones.

The DSS score's value to clinicians would be as a quick means to screen their patients' efforts and perhaps to use the tool to help trouble shoot, or to triage referrals to professional resources such as registered dietitians.

The value of the DSS score to researchers would be using this tool with shorter term studies as a means to predict whether or not their studied diets are likely to be sustainable (as who really cares how much weight a person might lose on a particular short term diet if few people would actually sustain it).

Of course now what's required is the repeated use of the Diet Satisfaction score in a long-term prospective trial. The good news is that because the tool, like me, is diet agnostic, it can be administered with any and all dietary strategies. Should you be interested in using the Diet Satisfaction Score in your trial Dr. Jospe is the person to contact and her contact information is just this one click away.

No Diet Works For Everyone, And Every Diet Works For Someone

As has been my tradition, in December I repost old favourites from years gone by. This year am looking back to 2016

Two weeks ago Kevin Hall and I had our diet commentary published in The Lancet. Not surprisingly, we upset some folks - primarily low-carbers. Some accused us of being low-fat cheerleaders. Others that we fostered an "animus" towards low-carb diets.

While I can't speak for Kevin, I can honestly state that I'm totally fine with low-carb diets. For some people they're a life changer and our office is happy to work with patients on them. I've also got nothing against low fat, Paleo, intermittent fasting, vegan, gluten-free, or any other diet that has a name.

What matters most to me, and what was also the crux of our commentary, is whether or not a person likes their chosen diet enough to sustain it. Food is not simply fuel. Food is comfort, food is celebration, and food serves as the foundation of a huge part of our social lives. Regardless of whether or not one diet vs. another diet affords a person an additional few pounds of loss (or even whether or not it confers specific health benefits) pales in importance to whether or not a person likes that diet's style of eating enough to live with it for good

As noted in our piece, every diet out there has its long term success stories, and so moving forward, if you see anyone out there suggesting their diet is the best (or that your diet is the worst) rest assured they have an agenda. Their agenda might simply reflect an n=1 mentality of, "it worked for me therefore it's what you should do", it might reflect basic post-purchase rationalization, or it might reflect genuine science and studies that infer greater short term losses or potential health benefits. But if they can't wrap their heads around adherence (which on an individual basis is an expression of whether or not you like what you're eating and don't miss what you're not) as any diet's long term's most critical component, their ideology is showing.

Temporary efforts will only yield temporary outcomes no matter how exciting the outcomes might be in the short run.

Real World Self-Selected Intermittent Fasting (IF) Vs. Continuous Energy Restriction (CER) Study Sees 73% of IF and 61% of CER Participants Not Lasting Even 6 Months

So what happens when you offer people with obesity the choice between 5:2 style intermittent fasting (IF) (very-low calories (VLC) 2 days weekly with 5 days of less restricted eating) and more traditional caloric restriction 7 days a week? Would encouraging people to choose between two strategies increase their likelihoods of successful weight management a year later? Would one group lose more weight than the other? Would adherence be the same?

That were the question post-doc RD Rona Antoni and colleagues set out to explore and they recently published a paper discussing their results.

197 patients with obesity presenting to the Rotherham Institute for Obesity were offered the choice between 5:2 IF (630 calories from liquid meal replacements on the VLC days), or an aimed 500 calorie continuous energy restriction (CER) 7 days per week with diet based off that recommended by the UK's dietary guidelines. Both groups received support from specialist obesity nurses for 6 months and were also asked to return for measurements and discussion at one year. All were also provided with access to, "a variety of specialist facilities, resources and multidisciplinary specialists including exercise and talking therapists", and all were reviewed in clinic monthly where measurements were taken (weight, total body fat, fat-free mass (FFM), waist circumference, systolic and diastolic blood pressure and an overnight fasted blood sample) and adherence was discussed.

99 patients chose IF, and 98 chose CER. 6 months later, 73% of IF patients and 61% of CER patients had dropped out. At one year, 83% of IF and 70% of CER patients were lost to follow up.

Of those who quit IF by 6 months, 18% explicitly reported they did so because they could not tolerate the diet, something that none of the CER drop outs reported, other IF drop outs reported they quit due to fainting or hypoglycemia on VLC days.

Regarding completers' weight losses at 6 months, the IF patients lost a statistically significant, but likely clinically meaningless, 4lbs more than the CER group. All blood measures (including fasting glucose, insulin, hsCRP, and lipids) were found to be the same between groups. Blood pressure changes were also not different between groups.

At one year, the 17 remaining IF patients were found to have regained their lost weight, while the 30 CER patients were found to be maintaining their albeit small amount (3%) of weight loss.

So what to make of this study?

I think the most striking finding was the overall 66% attrition rate across both arms. Certainly this study does not suggest that IF is an easier regime to follow than CER (at least not when provided at the Rotherham Institute for Obesity - given weight management support is a service and not a product, it's certainly possible that different providers might have seen different outcomes for both arms, but I do think this speaks to the challenge of scalability of behavioural interventions). But what I really think this study highlights is the fact that the real-world likelihood of purely dietary interventions treating our increasing weights is very low indeed. Instead, we need more tools for treatment (certainly including medications and surgeries), and more importantly, if we're going to see change, we're going to need environmental level changes to turn this boat around.

As to whether IF or CER will work for you don't forget that one person's horribly restrictive diet is another person's happy lifestyle. If you're trying to find your own right road, even if the first road fails, and even if angry diet gurus and zealots try to tell you there's no other road, keep trying different forks until you find the one that suits you best, as when it comes to diets, adherence is all that matters in the end, and if you don't like the way you're living, you're not likely to keep living that way.

What's The Point of Tracking Your Calories With a Food Logging App?

First up, the quantity and quality of calories matter both to health and to weight. You can't gain without a surplus. You can't lose without a deficit. And the quality of the calories you're consuming will affect health and satiety which in turn will affect the quantity of them that you consume. Moreover, the bioavailable calories you consume will differ by food, and also likely differs by individual (which is why some gain and lose with more ease than others).

Next up, we're crappy food historians. We may forget portions, choices, or both, not all the time, but certainly some of the time. We can't possibly know what's in meals we haven't cooked ourselves. And even if we are cooking ourselves, most aren't going to be weighing and measuring everything and eyes are terrible at both.

And a recent study confirms some of the above whereby researchers looking at users of myfitnesspal found the average user was missing nearly a meal's worth of calories a day (445). Yet studies on food diary use pretty much invariably report they markedly benefit weight loss efforts.

Personally, though I think having some rough inaccurate sense of caloric intake is valuable (if you were in a foreign country and didn't know the exchange rate, price tags would still be somewhat helpful), more valuable is the use of the food diary to remind yourself that you're trying to eat thoughtfully and likely differently.

Human nature being what it is, without a system designed to consciously remind you to change your usual default behaviours, you're likely to drift back to those behaviours, healthy or not, and a food diary, even if inaccurate, if kept in real-time, will remind you many times a day that you're trying to change.

So long as you're not using your food diary as a tool of judgment, as it's not meant to be there to make you feel badly about your choices, chances are it'll be of benefit, and likely it'll be of benefit regardless of what it is you're tracking (calories, macros, carbs, whatever) and even if inaccurate, because it's primary job is to serve you as your constant change reminder service, not as your judge and jury.

More On Set Points And Why I'm Not Fond Of Them

Seems my last post struck many different chords depending on the lens with which it was read.

Some people read it as stating that they're not trying hard enough.

Others read it as there's no point in trying.

Others agreed with me.

So for clarity, here's a bit more.

Me stating that lifestyles matter, that sociology matters, that our lives' patterns matter, and that they in turn help to explain why people often regain all of their lost weight when what's usually an overly restrictive weight loss effort is abandoned isn't me stating that people ought to be able to just tough out overly restrictive weight loss efforts. It's me pointing out that if your weight is currently stable, you're in equilibrium. You have, like we all do, an average daily caloric intake and output which of course includes things beyond your control (including genetics, medical co-morbidities and medications, job requirements and responsibilities, caregiver responsibilities, and more), out of the realm of your conscious ability to control (food marketing, societal and social norms, the constant, usually well-intentioned thrust of food at every turn, and more), and things that are unfair to expect you to control (largely the normal use of food to socialize with your friends and families). These are the sorts of the things that make up something some refer to as your "expososome", and I think the impact emigration tends to have on weight, which depending on your starting and finishing countries may well increase or decrease yours, is a clear example of how it influences your equilibrium. But regardless of your expososome, yes, there are things within your control to change that can affect your weight (though definitely not free from being influenced from many of those out of control factors) like how many meals you cook and your cooking skills, your liquid calorie consumption, your frequency of meals and snacks, the macronutrient composition of your diets, exercise, and more. And it's also true that for some, their lives' realities preclude intentional behaviour change.

What I was talking about yesterday, are the people who regain all of the weight they've lost with any given effort. These tend to be people who ultimately, for various reasons, are unable to continue with their change efforts. Instead, likely, not all at once, their efforts wane, then end, and those people find their way back to all of the original behaviours, factors, and choices that they were living with prior to their changes, which in turn brings back all of their old calories, eventually bringing their weights back to that same place where they were before (or perhaps even slightly higher consequent to metabolic adaptation leading them to burn fewer calories at a comparable weight than prior to their weight loss effort).

Why does this happen?

I think for a significant percentage of people it happens because the changes they employed were too severe. Maybe they were perpetually hungry, or denying themselves foods they loved and enjoyed, or they cut out entire food groups, or they found themselves unable to enjoy a meal out with friends, or regularly having to cook multiple meals (one for them, and one for their family). In short, the efforts many people undertake aren't by definition sustainable. They're for-now efforts, not for-good efforts. And I think the reason so many choose those types of approaches is that society (including the public health and research communities) generally describe total weight loss as the goalpost, and so people take on extreme efforts, because that's pretty much the only way to get there.

On the other hand, those individuals who lose weight and keep it off? While they nearly never are people who lose every last ounce that some stupid table says they should, there are huge numbers of them who've managed to lose a subtotal amount of weight and keep it off. Knowing these people, reading about these people, their most common denominator is that they enjoy the new lifestyles they've crafted sufficiently so as not to perceive them as suffering.

So if you want to lose weight, you're going to have to change some of those things that are within your control to change, but you're also going to have to pick changes that you can honestly enjoy if you want to keep the weight you lose, off. And different people, for a whole host of reasons, will have fewer things they're able to change, not to mention the fact that life and circumstances will also have a say as time goes by. But for everyone, change generally means embracing imperfection, still eating food for comfort and celebration, still socializing with friends and family, and more. And the degree of changes you'll be able to sustain will undoubtedly be impacted by many things beyond your control, and your physiology will undeniably limit your losses and the amount you're able to change without suffering. But that doesn't mean that physiology will prevent you from ever making any changes.

Maybe, if we all aimed for smaller, more realistic, less extreme, but all the while plainly sustainable changes, and as a society we stopped with Biggest Loser style efforts, and we redefined success, we'd see a great deal more of it.

Why I Still Have Issues With Set Point Theory And Weight Regain

Last week I watched a few people who I both follow and respect chat about set point theory - you know, the one that posits your body defends a particular weight such that after you lose, your body will in a sense strive to get back to where it started. And I tried to do so with an open mind, I really did, but I guess my own confirmation biases got the best of me because the conversation left me sighing.

That's not to say metabolic adaptation doesn't exist. It most certainly does. Metabolic adaptation is the catch-all term that refers to the very real fact that weight loss leads to a decrease in resting metabolism, a decrease in the thermic effect of meals (the cost of metabolizing what you eat), decreased energy cost of physical activity, and to changes to hunger hormones which in turn might well lead you to eat more. In general this also leads to the very real fact that weight loss is far from linear and that it usually stops sooner than expected or desired.

But it's the set point blamed regain back to starting weights that I struggle with conceptually.

Why?

Because generally speaking, it's presented as physiologically driven. My belief is that while metabolic adaptation definitely and somewhat depressingly affects how much weight might be lost with any given effort, it's really sociology that drive the bulk of most people's regains.

What I'm getting at is that people don't regain most or all of their lost weight because their bodies effectively tell them to, they regain most or all of their lost weights because when they quit whatever diets they were on, they revert back to the diets they were consuming beforehand, and by diets, I also mean lifestyles.

For instance, they might stop packing their lunches and head back to their cafeterias, food courts, or drive thrus. They might resume their regular nights out with friends and go back to drinking more alcohol and/or sugar-sweetened beverages. They might bring back some (or more likely all) of the snack foods and indulgences that they'd cut out while "being good". They might return to their older pre-established automated portion sizes and of course their older pre-established dietary staples.

In short, people regain their lost weights when they regain their lost lifestyles, as doing so brings them directly back up to their pre-weight loss average daily caloric intakes which in turn supported their pre-weight loss weights.

Which brings me back to another seminal confirmation bias of mine. The more weight you'd like to permanently lose, the more of your life you'll need to permanently change, which is why the world's best diet for you, is the one you actually enjoy enough to sustain. No, it might not lead you to lose as much as a magic wand would allow because metabolic adaptation does occur, but if you actually enjoy your new diet, and you don't head back to your old lifestyle when you quit the overly strict diet that's leaving you miserable, you need not worry that somehow, magically, due to a "set point", you're going to end up right back where you started.

Caring About The Quality of Your Food Is Not A Disorder (Orthorexia's Many False Media Positives)

That's not to say people can't see their concerns about diet quality not deteriorate into a disorder - where their concerns have sometimes even dramatically negative effects upon their qualities of life and/or mental health.

But that's not what I'm talking about here.

Here I'm talking about the knee jerk comfort people have in ascribing a disorder to someone else's dietary concerns or choices, especially in the both traditional and social media.

Just because you might personally find someone else's attention to their diet excessive, that doesn't mean it is to them. Their caring about the choice and types of their foods, so long as it isn't negatively affecting their physical health, mental health, or their quality of life, isn't an eating disorder!

Call For Help Part 2: Are You Currently On A Diet? Can You Take 2 Minutes To Complete A VERY Short Survey About It?

UPDATE: SURVEY CLOSED DUE TO RECEIVING SUFFICIENT RESPONSES. STAY TUNED FOR FUTURE SURVEYS THOUGH!

Today's survey is a followup to the one we sent out a few months ago. Since then we tweaked it on the advice of both those of you who responded, and some expert input. Even if you filled this out last time, we'd love for you to do so again as we're trying to iron out the kinks and I think (hope) we're pretty much there.

Back in 2012 I first posted my wish for there to be a questionnaire that would serve to help individuals and researchers determine how easy or difficult a particular diet would be to follow.

I called it the Diet Index Enjoyability Total or DIET score, and my hope was that by using a series of simple Likert scales (descriptive scales from 1-10), researchers could set out to evaluate a particular weight loss approach's DIET score where high scores would identify diets that could actually be enjoyed, and where low scores would identify under-eating, highly restrictive, quality of life degrading, dieting misery. This would be useful both to individuals who could use the DIET score to evaluate whatever approach they were considering, but might also serve as a surrogate for shorter term diet studies to give a sense as to whether or not there's a low or high likelihood of long term adherence to a particular study's strategy.

I'm happy to report that the first work on using the DIET score has been conducted by Michelle Jospe at the University of Otago in New Zealand as part of the SWIFT trial, and her and Jill Haszard's early look at the data is promising.

Part of the process required to validate a questionnaire involves a qualitative review to see whether or not it's easy to use, comprehensive, and unbiased, and this here is our second kick at that can.

Fast Initial Weight Loss The Secret To Success? Or Do Only Successful People Remain In Weight Loss Studies?

There was a lot of buzz last week about a new study that purportedly found that "fast initial weight loss may be key to diabetes prevention".

I say purportedly because the reporting wasn't about a published study, but rather a presentation given to the European Association for the Study of Diabetes (EASD) 2018 Annual Meeting on the to be published one day PREVIEW study.

The presentation reported that 3 years after an initial rapid, induced by meal replacement, weight loss, by way of 4 different dietary strategies, 96% had not developed type 2 diabetes.

This was contrasted apparently with the results of the Finnish Diabetes Prevention Study (DPS) and US-based Diabetes Prevention Program (DPP), neither of which included that initial rapid 2 month meal replacement loss, and where participants without diabetes at 3 years in the DPS and DPP were 91% and 86%, respectively.

So yes, the PREVIEW results were a touch better.

Or were they?

Whereas the DPS and DPP studies had tremendous retention of participants (92% and 92.5% respectively), PREVIEW's results come from just 41% of initial participants with 59% being lost to follow up at 3 years.

Which leads me to wonder whether PREVIEW's results are worthy of much publicity, as that's a tremendous loss to follow up, and it's quite plausible that the people most likely to follow up 3 years later, are the ones who did the best in sustaining their losses. I suspect therefore, that even here, success is dependent simply on adherence, and not on weight loss modality.

Finally, as always, I'll point out, that there is no one best way, and reporting like this, whether on a study with incredibly poor retention or otherwise, suggests to the public and to health care professionals that there may be one right or best way, despite the fact that different strategies will work differently for different people, which I would argue in turn, undermines patient care.

On Physicians Who Support, Promote, And Recommend, Only One Type Of Diet

Oh they're out there.

Tunnel vision physicians who believe that everyone should be vegan, or be intermittently fasting, or in ketosis, or on an incredibly low-fat diet, or vegetarian, or low carb high fat, - and I'm sure the list goes on.

It's a head scratcher for me because a physician's training ought to have them know better.

Why?

Because for virtually every medical problem, multiple therapies and therapeutic modalities exist. And because physicians know that some drugs work better than others with different patients - sometimes predictably, and sometimes unpredictably, and that sometimes people have adverse reactions to certain drugs that require them to try alternatives.

Diets are the same.

Whether for weight management, general health, or the treatment of particular medical conditions, certain patients, sometimes explicably and sometimes not, will do better with different diets, both in terms of the impact that diet has on whatever they're trying to treat, but also on their ability to enjoy that diet enough to sustain it long term.

And so even if there were a scientifically proven best diet for a particular issue (and for weight, plainly at this point, there isn't), there'll still be some people for whom it fails, and some people for whom its adverse effects on their lives leads to its discontinuation, and if they happen to be on that diet because they're following or seeing one of those MDs who is so stuck on there being only one diet to rule them all, I guess they're just out of luck.

So what drives those MDs? I think the answer varies. For some it's likely the extension of their own personal experience and success with a particular dietary approach. For others, it may be the consequence of literal or intellectually sunk costs. And finally some may not have sufficient background to evaluate much on their own and instead simply parrot an eloquently delivered diet zealot's talking points (perhaps especially in the cases of MDs converted by other MDs). But regardless of why one thing's for sure, the promotion of one right or best diet isn't good medicine, it compromises patient care, provides oxygen to the fire of fads, serves as catnip for publishers, the media, and the public, and solidifies the notion that there are dietary demons and deities, all of which in turn torches the hope of improved nutrition related scientific literacy in society.

Nutritional populism is a bad look irrespective of which diet it happens to be promoting.

[Photo by Anthony DeRosa from Pexels]

Meta-Analysis Of Low-Carb Meta-Analyses Finds The Ones Most Excited About Low-Carb Diets Are Of "Critically Low Quality"

Meta-analyses, studies that combine a slew of relevant studies to come to one larger conclusion, are undoubtedly valuable, but that doesn't mean there isn't plenty of room for debate about their findings.

Why?

Because their findings depend on the criteria they used in order to determine which studies should be included. So when considering a meta-analysis on the impact of low-carb diets (LCD), variables that would affect outcome might include the definition of LCD (ie how many grams per day of carbohydrates constitutes a low carb diet), the duration of the diet, the number of databases searched, how risk of bias was assessed and applied, and investigation of the causes of heterogeneity to name just a few of those found in the more complete (AMSTAR) list seen here:

And in fact, a study analyzing the quality of meta-analyses of low-carb diets was recently published in Obesity Reviews, and its findings fall in line with my very admitted confirmation bias which sees low-carb diets being as good or as bad as any other diet, and that at the end of the day, what matters more than the diet prescribed is diet adherence.

The authors found that,

"critically low quality (low-carb diet/LCD) meta-analyses showed superiority of LCD for weight loss while moderate quality showed inconsistent results, and high quality showed little or no difference"

Of course all of the studies included looked at overall losses between different prescribed diets, but in my opinion, that may not be the best way to evaluate them.

Because as the DIETFITs study so elegantly illustrated, there are people who do incredibly well with low-carb or low-fat diets, while other people do incredibly poorly, and all within the same study population.

I would argue further that this is true for any diet.

All this to say, be wary both of any study or meta-analysis that crowns one diet better than another, and of anyone suggesting that a particular diet isn't worth trying. One person's best diet is another person's worst.

(Photo by Jenna Hamra from Pexels)

New Intermittent Fasting Study: No Magic Weight Loss Benefits. Hungry Making.

If you even remotely follow dieting zeitgeist, there's no doubt you've come across intermittent fasting.

Briefly, intermittent fasting involves, yes, intermittently fasting. Sometimes for 8 hours a day. Sometimes for 24 hours. Sometimes even more.

And if you're wondering if it's for you, the simple answer is, if you find it helps you to control calories and weight, and you enjoy it enough to keep doing it, then go for it.

But putting aside the needing to enjoy living with it part for a moment, and assuming everyone could happily follow this strategy forever, would intermittent fasting lead to a greater weight loss than plain old old-fashioned dieting?

That was the question researchers in Norway recently took on, and their paper, Effect of intermittent versus continuous energy restriction on weight loss, maintenance and cardiometabolic risk: A randomized 1-year trial, has some answers.

The style of intermittent fasting they chose to study was the 5:2 style, whereby 5 days a week you eat normally, and then 2 days a week you eat no more than 400 calories if you're a woman, or 600 calories if you're a man. They compared a year worth of this approach to a year worth of reducing total daily calories by the same theoretical amount as the 5:2 fasting would provide but spread out evenly over 7 days rather than the 2. In all, 112 middle aged people with obesity were randomly assigned to one of the two treatments and then followed for a year - the first 6 months being a weight loss effort, and the next 6 months weight maintenance. All participants received individualized counselling, were trained in cognitive behavioural methods to help with adherence, and encouraged to follow, whether fasting or not, a Mediterranean style diet. The outcomes studied were weight loss, waist circumference, blood pressure. lipids (including ApoB), glucose, HbA1C, CRP, and RMR.

Participants were also asked to rate their degrees of hunger, well-being, and overeating quarterly.

Follow up was terrific, with only 4 lost in the intermittent fasting group, and 3 in the continuous.

Outcomes wise, at a year, weight loss (and the spread of weight loss with identical percentages of participants achieving 5-10% and >10% weight loss) and weight circumference were the same. There was also no difference to the various measured metabolic parameters.

In fact pretty much the only between group difference was hunger, whereby the intermittent fasters, when rating, "I have often felt hungry while on the diet", reported significantly more hunger (p=0.002).

Which brings me back to my wholly unsurprising tl:dr summary: Intermittent fasting provides no magical weight loss benefits, and is hungry making, but if you enjoy it, it'll probably work just as well, but not better, than anything else.

Have Diabetes And Motivated To Change Your Lifestyle? Virta (And Maybe #Keto) Could Be Right For You

A quick post regarding an exciting study that dropped today in the release of Virta Health's one year data on the impact their intensive lifestyle counselling, coupled with their ketotic diet, had on patients with type 2 diabetes.

The results were impressive.

Of the 262 patients who started the year long study, 83% finished, and of those their metabolic biomarkers and weight improved dramatically. On average their hemoglobin A1C (a long term measure of blood sugar) dropped from 7.6 to 6.3, type 2 diabetes medications other than metfromin dropped from 56.9% to 29.7%, and insulin was reduced or eliminated in 94% of subjects who started out on insulin, while sulfonylureas were eliminated entirely. Weight dropped an average of 30lbs. Insulin resistance as measured by HOMA-IR dropped by 55%, hs-CRP by 39%, and triglycerides by 24%. Though LDL did rise by 10%, HDL rose by 18% and apolipoprotein B was unchanged.

All this to say that if you have type 2 diabetes, and you're motivated to make lifestyle changes, Virta health's program definitely appears to be worth considering.

But there are some caveats.

Firstly the study looked at individuals who self-identified as wanting to affect lifestyle change, and so their comparison with "usual care", which consisted of individuals identified by their MDs as having diabetes and then being relegated to their local diabetes education program, may not be a fair one.

Secondly, the intervention was incredibly robust and intensive. That's not a knock. I think it's terrific. It included,

"continuous care through intensive, digitally-enabled support including telemedicine access to a medical provider (physician or nurse practitioner), health coaching, nutrition and behavior change education and individualized care plans, biometric feedback, and peer support via an online community"

And where behaviour change techniques taught included,

"education of natural consequences, shaping knowledge, goal setting, self-monitoring, feedback, monitoring and reinforcement from health coach and medical provider, self-belief, social support, relapse prevention, associations, and repetition"

Patients were provided a cellular connected body weight scale, a glucometer and ketometer, and a bp cuff. Patients were then given access to a web-based application to input data and where they received monitoring, education, and communication with their team.

Food wise participants reported daily hunger, cravings, energy, and mood by way of a Likert scale and health coaches worked with patients individually to adjust intake.

It is notable that daily protein intake was targeted to 1.5g/kg, and also that their weight losses had pretty much leveled off by year's end.

I bring up the robust intervention only in that I'm not aware of any prior interventions with other dietary strategies that would compare and therefore at this point it's difficult to divvy up what percentage of outcomes relate to the intensity and frequency of the intervention, and what percentage to their high protein, low-carb, ketotic diet.

The cost of Virta Health (if not covered by your insurer), is reported by them to be (I have no affiliation BTW) $400/month, but given the cost of diabetes medications and the outcomes reported herein, those costs may well be offset by your results.

What Are People Eating (And Not Eating) While Following A Low-Carb Diet?

Photo by Laurel F

Today's guest post comes from Dr. Nicola Guess who I invited to write about her recent study which explored what people on low-carb diets were and weren't eating. The tl;dr version? At least according to their dietary recall, they ate more whole foods, and far less in the way of liquid sugars and combination high-fat, high sugars foods (the ultra-processed stuff) - a potentially more sating pattern, and definitely not one that raises any alarm bells. And just an FYI, Dr. Guess is also very active on Twitter and is definitely worth a follow.

Carbohydrate restriction can be very helpful in the management of type 2 diabetes, particularly with controlling blood sugar levels. However, there have been several concerns cited about low-carbohydrate diets which I think hinders the widespread recommendation of this dietary approach for management of type 2 diabetes. For example, people might be limiting nutrient-rich foods such as fruits, vegetables and pulses. Others might be consuming a very narrow range of foods such as diets characterised by sausages, burgers and butter, with the occasional fried tomato thrown in. Despite the apparent popularity of low-carbohydrate diets, I realised that outside of clinical trials where the diet is prescribed by researchers, very little is actually known about what foods people eat when restricting dietary carbohydrates.

I therefore sought to examine this question by using national dietary surveys in the UK. Earlier this year I examined the National Diet and Nutrition Survey and found that people on a reduced carbohydrate diet (fewer than 40% of kilocalories from carbohydrate) consumed more red and processed meat, butter, oily fish and vegetables, as well as a lower consumption of soft drinks and pulses than people on a higher carbohydrate intake. I could not examine the intake on a low-carbohydrate diet (of which a suggested definition is fewer than 26% of calories from carbohydrates) because only 15 people out of 2263 followed this pattern.

Fortunately, the UK BIOBANK offered the opportunity for me to examine this question in a larger dataset. The UK BIOBANK is a huge population study in the UK which has collected comprehensive demographic, biochemical and lifestyle data in over 500,000 people. Dietary data was collected using a short food frequency and dietary habits questionnaire on the first visit. This basically asked how often people have different types of meat, oily fish, fruits, vegetables and alcohol, and also what type of spread, cereal and bread people consumed. In addition, a 24-hour dietary recall was completed on up to five further occasions. A 24-hour dietary recall asks the participant what food or drinks they consumed over the previous 24-hours, including the portion size of each food or drink consumed.

Using this dataset I was able to compare the dietary intake of people consuming fewer than 26% of kilocalories from carbohydrates to those consuming 45% or more. Confirming the findings from my earlier study, I found that a low-carbohydrate dietary pattern was associated with a significantly higher intake of red meat, oily fish, nuts and seeds but fewer fruits, vegetables and pulses compared to the normal carbohydrate group. In general the consumption of nutrient-rich foods such as nuts, seeds, oily fish and pulses were low in both groups. However, most striking was the difference in the intake of high-sugar, high-fat foods and snacks such as doughnuts, biscuits, cakes, pastries and ice cream. People in the normal carbohydrate group reported a much higher consumption of these foods (a median of six across the five dietary recalls) compared to the low carbohydrate groups (a median of zero!). This mirrored a result from my earlier study - that total carbohydrate restriction is associated with a preferential restriction of foods high in added sugars - a dietary change almost certainly likely to improve health outcomes.

The other striking finding was how few people actually reported a dietary intake consistent with a low-carbohydrate diet. Out of over 210,000 people who had completed dietary data, only 444 had a low-carbohydrate diet as defined by fewer than 26% kcal from carbohydrate. 1953 people reported consuming less than 130g of carbohydrate per day, which is another definition used for a low-carbohydrate diet. In an earlier study in the US, out of over 10,000 people in the Continuing Survey of Food Intake by Individuals, only 412 reported consuming a diet with fewer than 30% kilocalories from carbohydrates. There could be many reasons for this. Potentially, these types of dietary surveys might attract people who are engaged with conventional health advice, and therefore more likely to follow the type of diet recommended by national guidelines. Another reason may be that a low-carbohydrate diet is difficult to follow for most people. It’s worth mentioning that the low-carbohydrate groups had a higher BMI in each of the three dietary surveys I mentioned above. It’s possible that people with a higher BMI were following this diet to try to help them lose weight, but the low overall number reflects the difficulty in sustaining this diet long-term.

A limitation of our study is that we cannot tell whether people were intentionally following a low-carbohydrate pattern. Therefore I next plan to follow people prospectively as they adopt a low-carbohydrate diet. I hope this research helps us understand what foods people consume on a low-carbohydrate diet (especially people on a low-income) and can aid us in offering dietary advice to people wanting to follow this dietary approach.

Shafique M, Russell S, Murdoch S, Bell JD, Guess N. Dietary intake in people consuming a low-carbohydrate diet in the UK Biobank. J Hum Nutr Diet. 2017 Dec 13.

Guess N. Dietary intake in people consuming a reduced-carbohydrate diet in the National Diet and Nutrition Survey. J Hum Nutr Diet. 2017 Jun;30(3):360-368.

Kennedy ET, Bowman SA, Spence JT, Freedman M, King J. Popular diets: correlation to health, nutrition, and obesity. J Am Diet Assoc. 2001 Apr;101(4):411-20. Review.

Dr Nicola Guess is a lecturer in the Department of Nutritional Sciences at King’s College London in the UK and a Registered Dietitian. Her research interests are on the effect of diet on the pathophysiology of type 2 diabetes. 

New Study Suggests If Anything, Fasting More Difficult For Long Term Weight Loss

You might be able to buy a bowl like this here.

Now let me be clear right out of the gate, the study I'm about to discuss found that alternate day fasting led to just as much weight loss as tracking calories. But there was one difference.

The study, a randomized, controlled, year long affair assigned 222 patients to either:

1. Alternate day fasting
2. Daily calorie restriction
3. Nothing

For the first 3 months, both the fasting group and the calorie restriction group received all their meals from the study coordinators. For the next 3 months, both groups were encouraged to reduce their energy intake by 25% per day. The fasters were told to consume 25% of their baseline daily calories as a lunch (between 12 pm and 2 pm) on fast days and 125% of their baseline daily calories split between 3 meals on alternating feast days. The calorie restrictors were told to consume 75% of their baseline daily calories split between 3 meals. For the last six months, following the calculation of total daily energy expenditure (by way of doubly labeled water), participants were instructed to maintain their body weights. Fasters were advised to consume 50% of their calculated energy needs at lunch on fast days, and 150% of their energy needs split between 3 meals on alternating feast days. Restrictors were told to stop restricting and instead to consume 100% of their energy needs split between 3 meals.

Throughout it all, both intervention groups received support and counselling from RDs.

The study's primary outcome was weight loss. Physical activity was controlled for and calculated by two 1 week periods of accelerometer use. Dietary adherence was monitored by way of food recall.

Secondary outcomes were blood pressure, heart rate, total cholesterol, low-density lipoprotein cholesterol, high-density lipoprotein cholesterol, triglycerides, fasting glucose, fasting insulin, C-reactive protein, and homocysteine concentrations.

Weight loss wise, as you can see from the graph, at virtually no point in time during the year long study was there was a difference found between fasters and restrictors (triangles and squares).

There were also no statistically significant changes found to body composition between the groups.

At 12 months, there were also no differences to be found in any of the secondary outcomes or measures.

In fact the only difference the researchers found was to adherence.

More people dropped out of the fasting intervention (38%) than of the restricting intervention (29%).

I'm not sure how surprising that finding is, as fasting may be challenging for many with respect to lifestyle including to family meal times, socializing with friends, and eating with coworkers.

Or maybe it leads people to be more hangry?

All this to say, if you enjoy fasting as a lifestyle, go for it. But no, it doesn't appear, at least not from this study, that fasting has any magical properties.

No Diet Works For Everyone and Every Diet Works For Someone.

Two weeks ago Kevin Hall and I had our diet commentary published in The Lancet. Not surprisingly, we upset some folks - primarily low-carbers. Some accused us of being low-fat cheerleaders. Others that we fostered an "animus" towards low-carb diets.

While I can't speak for Kevin, I can honestly state that I'm totally fine with low-carb diets. For some people they're a life changer and our office is happy to work with patients on them. I've also got nothing against low fat, Paleo, intermittent fasting, vegan, gluten-free, or any other diet that has a name.

What matters most to me, and what was also the crux of our commentary, is whether or not a person likes their chosen diet enough to sustain it. Food is not simply fuel. Food is comfort, food is celebration, and food serves as the foundation of a huge part of our social lives. Regardless of whether or not one diet vs. another diet affords a person an additional few pounds of loss (or even whether or not it confers specific health benefits) pales in importance to whether or not a person likes that diet's style of eating enough to live with it for good

As noted in our piece, every diet out there has its long term success stories, and so moving forward, if you see anyone out there suggesting their diet is the best (or that your diet is the worst) rest assured they have an agenda. Their agenda might simply reflect an n=1 mentality of, "it worked for me therefore it's what you should do", it might reflect basic post-purchase rationalization, or it might reflect genuine science and studies that infer greater short term losses or potential health benefits. But if they can't wrap their heads around adherence (which on an individual basis is an expression of whether or not you like what you're eating and don't miss what you're not) as any diet's long term's most critical component, their ideology is showing.

Temporary efforts will only yield temporary outcomes no matter how exciting the outcomes might be in the short run.

In The Lancet, Kevin Hall and I Call Out Weight Loss Studies

Today my piece with the NIH's Kevin Hall was published in The Lancet. The piece, reproduced below, speaks to the lack of clinical utility of large swaths of the weight loss literature and suggests an alternative direction to consider with future studies.

Weight loss diet studies: we need help not hype

Over the past several decades, dozens of randomised controlled trials have compared various diets for the treatment of obesity. Ideally, such studies should have provided strong evidence for clear clinical recommendations and also put a stop to society’s endless parade of fad diets. Unfortunately, the evidence base remains contested and the “diet wars” continue unabated.

One insight that can be gleaned from the existing weight loss literature is that even the most divergent of diets seem capable of affecting a degree of short-term success, with some diets perhaps leading to marginally greater losses than others over periods of several months.1 But since obesity is a chronic condition, it is the long term that matters. An effective diet for clinical weight management needs to be established over time scales of years to decades. Studies that have lasted 1 year or more typically do not show significant differences between prescribed diets, much less any clinically meaningful differences in maintenance of lost weight.1, 2 One example is in the Dietary Intervention Randomized Controlled Trial (DIRECT), which has been hailed as proof of the superiority of low-carbohydrate diets over low-fat diets.3,4 The DIRECT investigators used a 2-year workplace intervention and found that a low-carbohydrate diet prescription led to a significant 1·8 kg greater mean bodyweight loss than the prescription of a low-fat diet.3,4 These bodyweight differences between the diets are among the largest differences that have been observed over a 2-year period. But from the clinical perspective, such small bodyweight differences do not instil confidence for prescribing one diet over another to a patient with obesity.

What is especially striking is the similarity of the long-term pattern of mean bodyweight change, irrespective of diet prescription.5 For example, figure 1A shows data from the DIRECT study in which both the low-fat and low-carbohydrate diets resulted in rapid early weight loss that plateaued after about 6 months at a likely disappointing level6 and was then followed by slow bodyweight regain. What can we learn from the physiology underlying such a bodyweight trajectory?

Complex physiological feedback mechanisms regulate bodyweight and resist weight loss. Slowing of metabolism can be substantial and persistent7 and plays a part in halting weight loss and putting subsequent weight regain into motion. However, the typical bodyweight trajectory is primarily driven by patients experiencing an exponential decay of diet adherence due to an increase in appetite in proportion to the loss of bodyweight,8 along with difficulties in sustaining changes to dietary choices and behaviours that affect patients’ ability to enjoy, celebrate, and socialise with food.

Figure 1B shows the energy intake changes underlying the DIRECT trial’s observed bodyweight trajectories, which we have calculated using a validated mathematical model of human energy metabolism and bodyweight dynamics.9 At the plateau point of maximum weight loss, energy intake is balanced by expenditure and has decreased from baseline by about 200 kcal per day. By contrast, mean energy intake at the bodyweight plateau has increased by about 700–1000 kcal per day from its early reduction at the start of the intervention. After 1 year, mean bodyweights, although still reduced by several kilograms, climb back up in response to the average energy intakes returning almost to baseline levels.

Diet adherence is so challenging that it is poor even in short-term studies where all food is provided.10 When diets are prescribed, adherence is likely to diminish over the long-term despite self-reports to the contrary. Figure 1B illustrates that the common self-report methods for measuring food intake (24 h recall and food frequency questionnaire3,4) mistakenly indicate that the reduction in energy intake remained unchanged throughout the intervention. Such erroneous measurements have led to speculation that a reduction in energy expenditure, rather than loss of diet adherence, is the main driver of the bodyweight plateau. However, these self-reported measurements are known to be inaccurate for estimating energy intake11 and provide unreliable data on energy intake changes that are not quantitatively reconcilable with objectively measured weight regain and the known physiology of energy metabolism adaptations.

The similarity of mean bodyweight trajectories between long-term diet interventions, whether targeting macronutrients, calories, or food patterns, is explained by the fact that no diet has yet been shown to be uniformly easier to stick with than another in the long run. If there existed a diet that led to substantially improved long-term adherence in most patients—because it better addressed appetite changes, provided a sustained metabolic advantage, or was simply easier for patients to maintain—such effects would result in substantial and sustained differences in mean bodyweight. This result has not been observed despite repeated efforts using widely different diets.

Nevertheless, and hearteningly, anecdotal long-term diet success stories abound for most dietary approaches, and focusing on mean bodyweight trajectories masks the high individual weight loss variability within each diet group. The question is: why are some individuals more successful than others? When it comes to clinical weight management, success is predicated on long-term dietary adherence. Therefore, we need to increase our efforts to understand the individual differences between patients that have an effect on diet maintenance and prevent its erosion. Studies should determine how to target effective diets to individual patients,12 as well as improve our understanding of the real world considerations that impinge on patients’ abilities to sustain healthy dietary changes,13 such as those wrought by the food environment, socioeconomic factors, cooking skills, job requirements, medical comorbidities, caregiving responsibilities, and many more. After all, as with every chronic disease, successful obesity management requires lifelong treatment and there is a pressing need to help patients navigate day-to-day realities in the face of maintaining a permanent and intentional behaviour change. We also need to better understand how family, community, and society as a whole can help support and sustain healthy lifestyles.

Fewer resources should be invested in studying whether or not a low-carbohydrate diet is marginally better than a low-fat diet, or whether intermittent fasting provides marginally better short-term outcomes than a so-called Paleo diet. Crowning a diet king because it delivers a clinically meaningless difference in bodyweight fuels diet hype, not diet help. It’s high time we started helping.

Yoni Freedhoff, *Kevin D Hall

YF has received honoraria and travel expenses from Boston Children’s Hospital, Canadian Obesity Network, Centre for Effect Practice, Academy of Medicine Ottawa, Physical and Health Education Canada, North York General Hospital, , IDEA Health and Fitness Association, and the Royal Society of Medicine, London, for speaking engagements and for his role as clinical lead in the development of a Canadian Ministry of Health funded tool for primary care providers working with families of children with obesity; and has received fees for developing and delivering educational seminars to medical students and residents from the University of Ottawa. YF writes a blog, Weighty Matters, that is non-monetised with no advertisements or requests for donations. YF is the co-author of Best Weight: A Practical Guide to Office-Based Obesity Management all royalties from the book go to the Canadian Obesity Network and he is the author of The Diet Fix (Random House) and receives royalties from this book. KDH reports a patent pending on a method of personalised dynamic feedback control of bodyweight (US Patent Application No. 13/754,058; assigned to the National Institutes of Health) and has received funding from the Nutrition Science Initiative to investigate the effects of ketogenic diets on human energy expenditure.

1 Johnston BC, Kanters S, Bandayrel K, et al. Comparison of weight loss among named diet programs in overweight and obese adults: a meta analysis. JAMA 2014; 312: 923–33.
2 Tobias DK, Chen M, Manson JE, Ludwig DS, Willett W, Hu FB. Effect of low-fat vs. other diet interventions on long-term weight change in adults: a systematic review and meta-analysis. Lancet Diabetes Endocrinol 2015; 3: 968–79
3 Greenberg I, Stampfer MJ, Schwarzfuchs D, Shai I. Adherence and success in long-term weight loss diets: the dietary intervention randomized controlled trial (DIRECT). J Am Coll Nutr 2009; 28: 159–68.
4 Shai I, Schwarzfuchs D, Henkin Y, et al. Weight loss with a low-carbohydrate, Mediterranean, or low-fat diet. N Engl J Med 2008; 359: 229–41.
5 Franz MJ, VanWormer JJ, Crain AL, et al. Weight-loss outcomes: a systematic review and meta-analysis of weight-loss clinical trials with a minimum 1-year follow-up. J Am Diet Assoc 2007; 107: 1755–67.
6 Foster GD, Wadden TA, Vogt RA, Brewer G. What is a reasonable weight loss? Patients’ expectations and evaluations of obesity treatment outcomes. J Consult Clin Psychol 1997; 65: 79–85.
7 Fothergill E, Guo J, Howard L, et al. Persistent metabolic adaptation 6 years after “The Biggest Loser” competition. Obesity (Silver Spring) 2016; published online May 2. DOI:10.1002/oby.21538.
8 Polidori D, Sanghvi A, Seeley RJ, Hall KD. How strongly does appetite counter weight loss? Quantification of the feedback control of human energy intake. Obesity (Silver Spring) 2016 (in press).
9 Sanghvi A, Redman LA, Martin CK, Ravussin E, Hall KD. Validation of an inexpensive and accurate mathematical method to measure long-term changes in free-living energy intake. Am J Clin Nutr 2015; 102: 353–58.
10 Das SK, Gilhooly CH, Golden JK, et al. Long-term effects of 2 energy-restricted diets differing in glycemic load on dietary adherence, body composition, and metabolism in CALERIE: a 1-y randomized controlled trial. Am J Clin Nutr 2007; 85: 1023–30.
11 Dhurandhar NV, Schoeller DA, Brown AW, et al. Energy balance measurement: when something is not better than nothing. Int J Obes (Lond) 2015; 39: 1109–13.
12 Bray MS, Loos RJ, McCaffery JM, et al. NIH working group report-using genomic information to guide weight management: from universal to precision treatment. Obesity (Silver Spring) 2016; 24: 14–22.
13 MacLean PS, Wing RR, Davidson T, et al. NIH working group report: innovative research to improve maintenance of weight loss. Obesity (Silver Spring) 2015; 23: 7–15

Will Personalized Genetic Risk Knowledge Lead People to Change Their Diets?

Image Source: ThinnerGene

Certainly that's the notion behind the rise of the for-profit personalized medicine genetic testing industry. The thinking is that if people are made aware of their personalized genetic risks, and if those risks are modifiable by way of diet, that said knowledge will motivate people to affect dietary changes.

But does it?

That's the question a recently published randomized trial sought to answer. The study, The effect of the apolipoprotein E genotype on response to personalized dietary advice intervention: findings from the Food4Me randomized controlled trial, randomly assigned 1,466 participants to a 6 month trial of one of 4 interventions.

1. Standard non-personalized dietary and physical activity advice
2. Personalized advice based on dietary intake
3. Personalized advice based on dietary intake, physical activity, and standard blood biomarkers
4. Personalized advice based on dietary intake, physical activity, standard blood biomarkers, and genotyping

The genotyping was for apolipoprotein E (APOE) which in turn is thought to be a key regulator of cholesterol and lipids. It's also thought that differing APOE genotypes influence lipid responses to dietary fat and therefore given the known increased risk of certain APOE genotypes with coronary heart disease and on lipid responses to dietary fat, that risk carrying individuals if told about their genotypes, might be more likely to adopt gene-based personalized nutrition recommendations.

The study's findings aren't particularly heartening for personalized medicine as it pertains to individual behaviour change.

Personalized advice was found to be better than non-personalized advice, but there was no additional benefit to change found with those whose personalized advice warned them that their unique genetic makeups conferred greater risk.

There is a silver lining here though. Personalized advice based on an individual's dietary intake alone was just as likely to inspire change. So rather than spending your money on all sorts of tests, if you're worried about some diet related aspect of your health, go see an RD (but maybe not one who tries to sell you personalized genetic testing), and with the money you save on all that other testing, you can book a few follow ups and likely get an even bigger bang for your buck.

Why I'll Never Prescribe a Very-Low-Energy Diet

A VLED is a "very low energy diet", and it's defined as one providing fewer than 800 calories per day. These programs are generally administered by physicians, are expensive, often take the form of meal replacement shakes, and usually last for around 12 weeks.

Multiple meta-analyses on VLEDs have been conducted, and generally their findings haven't been particularly exciting. Either they've concluded they aren't worth prescribing, or they've concluded that there isn't sufficient information for a conclusion.

Well add another meta-analysis to the pile. This one, published in March in Obesity Reviews, had what I found to be a very odd conclusion, and I'll get there in a bit. Ultimately the researchers findings were that when compared with a standard, and non-extreme, behavioural weight loss program, 3-5 years later, VLED patients will have lost 2.86lbs more.

Bare in mind too, VLEDs are challenging for patients. Can you imagine 12 weeks of just shakes? I've heard stories of people having to bring their meal replacement shakes to weddings, or to chug them in place of Christmas dinner. VLEDs have risks too. Gallstones from overly rapid losses, disproportionate loss of muscle mass, and electrolyte abnormalities.

So when I read that 5 years later, with VLED diets being shown to affect an additional half pound lost per year, and with their associated risks, and their not insignificant costs (both actual dollars and the cost to a patient's ability to live a normal life), I figured that certainly, the authors' conclusion will have to be that there's not much point in recommending them to patients.

Nope.

Despite VLEDs being found to barely lead to additional losses, despite their risks and their costs, the study's authors concluded,

"Adding a VLED to a behavioural weight loss programme produces greater weight loss in the medium and longer term than a behavioural programme alone. Such programmes appear well-tolerated. Current advice against their use for routine weight loss in medical clinics should be reconsidered."

Huh? Am I missing something?

While there are true success stories with every approach (including VLEDs), weight lost through suffering tends to come back.