Monday, August 19, 2019

9 Great Suggestions For Improving The Quality Of Dietary Research (And 1 That According To @JamesHeathers Is "Deeply Silly")

Last week saw the publication of an op-ed authored by Drs. David Ludwig, Cara Ebbeling, and Steven Heymsfield entitled, "Improving the Quality of Dietary Research". In it they discuss the many limitations of dietary research and chart a way forward that includes the following 9 great suggestions,
  1. Recognize that the design features of phase 3 drug studies are not always feasible or appropriate in nutrition research, and clarify the minimum standards necessary for diet studies to be considered successful.
  2. Distinguish among study design categories, including mechanistic, pilot (exploratory), efficacy (explanatory), effectiveness (pragmatic), and translational (with implications for public health and policy). Each of these study types is important for generating knowledge about diet and chronic disease, and some overlap may invariably exist; however, the findings from small-scale, short-term, or low-intensity trials should not be conflated with definitive hypothesis testing.
  3. Define diets more precisely when feasible (eg, with quantitative nutrient targets and other parameters, rather than qualitative descriptors such as Mediterranean) to allow for rigorous and reproducible comparisons.
  4. Improve the methods for addressing common design challenges, such as how to promote adherence to dietary prescriptions (ie, with feeding studies and more intensive behavioral and environmental intervention), and reduce dropout or loss to follow-up.
  5. Develop sensitive and specific biomeasures of adherence (eg, metabolomics), and use available methods when feasible (eg, doubly labeled water method for total energy expenditure).
  6. Create and adequately fund local (or regional) cores to enhance research infrastructure.
  7. Standardize practices to mitigate the risk of bias related to conflicts of interest in nutrition research, including independent oversight of data management and analysis, as has been done for drug trials.
  8. Make databases publicly available at time of study publication to facilitate reanalyses and scholarly dialogue.
  9. Establish best practices for media relations to help reduce hyperbole surrounding publication of small, preliminary, or inconclusive research with limited generalizability."
But there is one recommendation that seems at odds with the rest,
Acknowledge that changes to, or discrepancies in, clinical registries of diet trials are commonplace, and update final analysis plans before unmasking random study group assignments and initiating data analysis.
For those who aren't aware, clinical registries are where researchers document in advance the pre-specified methods and outcomes being studied by way of an observational experiment. The purpose of pre-registration is to reduce the risk of bias, selective reporting, and overt p-hacking that can (and has) occurred in dietary research.

Now to be clear, I'm a clinician, not a researcher, and I'm not sure how commonplace changes to or discrepancies in clinical registries of diet trials are, but I'm also not sure that's an argument in their favour even if they are. I do know that recently two of the authors claiming registry changes are commonplace were found to have modified one of their pre-specified statistical analysis plans which if it had been adhered to, would have rendered their results non-significant.

But commonplace or not, is it good science?

To answer that question I turned to James Heathers, a researcher and self-described "data thug" whose area of interest is methodology (and who you should definitely follow on Twitter), who described the notion of accepting that changes and discrepancies to clinical registries were commonplace was, "deeply silly".

He went on to elaborate as to why,
First of all - the whole definition of a theory is something which sets your expectations. the idea that 'reality is messy' does not interfere with the idea that you have hypothesis driven expectations which are derived from theories.

Second: there is nothing to prevent you saying "WE DID NOT FIND WHAT WE EXPECTED TO FIND" and then *following it* with your insightful exploratory analysis. In fact, that would almost be a better exposition of the facts by definition as you are presenting your expectations as expectations, and your after-the-fact speculations likewise.

Third: if you have a power analysis which determines there is a correct amount of observations necessary to reliably observe an effect, having the freedom to go 'never mind that then' is not a good thing by definition.

Fourth: The fact that changes were made is never ever included in the manuscript. i.e. they are proposing being able to make changes to the protocol in the registry *without* having to say so. it's a 'new plan' rather than a 'changed plan'.

Fifth: If you can still do the original analysis then no-one will ever believe that you didn't change the plan after looking at the data. you have to protect yourself, and the best way to do that is to follow your own damned plans and be realistic from the get.
Lastly, Heathers is unimpressed with the argument that registry changes are A-OK because they're commonplace, and he discussed ancient Aztecan punishments for those citing it.

All this to say, there's plenty of room to improve the quality of dietary research. Here's hoping the bulk of these suggestions are taken to heart, but please don't hold your breath.

Saturday, August 17, 2019

Tuesday, August 13, 2019

Kellogg's Partners With Random House To Use Free Books To Sell Ultra-Processed Sugary Junk Food To Children

To be clear, neither Random House, nor Kellogg's, should be fairly expected to do the right thing when it comes to health.

Kellogg's job is to sell food. Random House's job is to sell books. Nothing more, nothing less.

So it's hard to get mad with either company for their "Feeding Reading" initiative which provides parents with permission or excuse to buy their children such health foods as:
  • Frosted Flakes
  • Pop-Tarts
  • Eggos
  • Nutrigrain Bars
  • Froot Loops
  • Rice Krispie Treats
  • Apple Jacks
  • Frosted Mini-Wheats (note, unfrosted mini-wheats are not eligible)
  • Corn Pops
  • Raisin Bran
  • Krave
  • Keebler cookies
  • Cheez-its
  • Austin crackers
  • Pringles
Truly, not a single choice parents or children should be encouraged to make. All ultra-processed, sugary, junk (and some crackers and potato chips).

Again, no reason to expect either Random House or Kellogg's to be doing the right thing by kids, but in my opinion, their clear partnership in doing the wrong thing here certainly doesn't reflect well on either of them.

Tuesday, August 06, 2019

The Recipe For Aging Gracefully And Adding Life To Your Years

No one wants aging to happen to them, and yet.

While eventually we'll all lose the fight, that doesn't mean we can't go down swinging, and the good news is the recipe for aging without frailty is exceedingly straight forward and was recently spelled out in a systematic review published in the British Journal of General Practice.

The magic formula the 46 included studies pointed to? A mix of regular strength training with regular protein supplementation.

Spelled out a bit further?

20-25 minutes of strength training 4x per week and the purposeful inclusion of protein with every meal and snack (or alternatively, two daily protein supplements providing 25g of protein each).

Though the aforementioned formula won't guarantee a long life, the evidence certainly suggests it'll help to provide a better one adding life to your years if not years to your life.

Monday, July 29, 2019

Most Generous Conclusion Of Chocolate Milk In Exercise Systematic Review And Meta-Analysis? It Will Increase Your Time To Exhaustion By 47 Seconds Over Placebo

Literally every time I write about chocolate milk being a beverage worth actively minimizing in your diet (have the smallest amount of it you need to like your life), someone inevitably chimes in to tell me I'm wrong because it's great for exercise recovery.

And I'm not sure how I missed this when it came out, but last year, the European Journal of Clinical Nutrition, published a systematic review and meta-analysis of randomized controlled trials involving chocolate milk and exercise recovery.

After excluding studies that didn't meet their inclusion criteria, the (non-conflicted) authors were left with 12 studies, 2 deemed of high quality, 9 of fair quality, and 1 of low quality with 11 having extractable data on at least one performance/recovery marker including ratings of perceived exertion, time to exhaustion, heart rate, serum lactate, and serum creatine kinase.

Their overall conclusion?

The systematic review and meta-analysis revealed that chocolate milk consumption had no effect on any of those variables when compared to placebo or other sport drinks.

Their most generous conclusion?

If they excluded one study from their analysis of the effect of chocolate milk on time to exhaustion then chocolate milk was found to increase time to exhaustion by 47 seconds over a placebo beverage. They also found, in another subgroup analysis, that lactate was slightly attenuated in chocolate milk drinkers compared to placebo (a finding that was not present in the high quality RCT looking at same).

(for a brief discussion on the stats involved and the subgroup analysis, here's a post on same from epidemiologist @GidMK who concluded that chocolate milk is "not a fitness drink").

Happy to have this post published so that I can share the next time someone inevitably tries to suggest that chocolate milk is magic.

Saturday, July 27, 2019

Thursday, July 25, 2019

Sorry, Eating Thin People's Poop Isn't Likely To Make You Thin

Though there are certainly some celebrity quacktacular physicians I would like to see eat crap, but what I wouldn't be able to tell them is that doing so would likely have a beneficial impact on their weights.

A recent small study, Effects of Fecal Microbiota Transplantation With Oral Capsules in Obese Patients, found results that to me at least, seemed wholly unsurprising. 22 patients with obesity were randomly assigned to receive either a "fecal microbiota transplantation" from a donor whose BMI was 17.5 or a placebo and to take them for 3 months (and for those curious, the induction dose was 30 capsules).

The transplants were successful in changing the microbiome of the recipients, but alas, did not affect their weights.

Perhaps the only thing surprising about all of this is that there are people out there who strongly believe that a microbiome transplant stands a chance against thousands of genes, dozens of hormones, and a Willy Wonkian food environment all of which being coupled with millions of years of an evolutionary crucible of extreme dietary insecurity.