Diet Book Review: The 8-Hour Diet

[Full disclosure: I was sent a free review copy by the publisher]
There's a good reason why The 8-Hour Diet reads like a Men's Health magazine article - it was authored by David Zinczenko, former Editor in Chief of Men's Health magazine. The hyperbole begins even before the book does. Here's the jacket cover (Caps lock and bolding theirs),

"In just 6 weeks you're going to have your best body ever. You'll be LEANER, HEALTHIER, MORE ENERGETIC. You'll have the flat, firm belly you've always wanted. You'll sleep better, think more clearly-and have much better sex. You'll look younger, feel younger, and dramatically cut your risk of the major diseases of our time.

You'll lose weight faster than ever-as much as 5 pounds a week-without restricting calories OR giving up your favourite foods."

The promise of the book is simple. Here's Zinczenko's version of it taken from the very first 3 pages of the book,

"Imagine the freedom that would come from being able to do whatever you want, eat whatever you want and know - not think, not hope, but know for certain - that you'll never gain another pound."

"Eat whatever you want as much as you want. But only eat during an 8-hour period each day (with a few cheats thrown in here and there!).

"And the most remarkable thing of all: You only have to follow the diet 3 days a week. Three days a week!"

And that message of eating as much as you want of whatever you want (who wouldn't want that in a weight loss plan?) is reinforced over, and over again throughout the book,

"In fact the only challenge to the 8-Hour Diet is finding time to eat lots of delicious food. Heck, you should probably put your favorite barbecue joint on speed dial - just so you can satisfy your most gluttonous cravings at the touch of a button!"

Of course there a tiny bit more to it, and I'll get to that in a bit, but first the science.

There is science backing up intermittent fasting (fast intermittently for 16 or more hours and then eat). Like all areas of research, some of the science is stronger than others, some is weak, and some is crippled by poor methodologies or statistics, however unlike most of the diet books I've recently read, Zinczenko doesn't provide us with his actual references (so if you were interested you could check out the data for yourself) despite virtually every page concluding on the basis of one uncited study or another that certain foods are "Fat Busters", or "Health Boosters", or that fasting improves every last aspect of your life, weight and metabolism. I wonder if part of his reticence to include his sources is the fact that much of the research that has been done on fasting has been done on fasts that are longer, and hence perhaps not applicable, to his 16 hour recommendations, or that the studies themselves while interesting, may not be as conclusive as he's suggesting.

What's also upsetting is the fact that Zinczenko makes no mention of a man named Martin Berkhan. Martin is a Swedish bodybuilder who as far as I'm aware, is the first person to lay out The 8-Hour Diet. Here's an excerpt from Martin's first blog posting from June 15th, 2007,

"the protocol consists of a fasting period, lasting 16 hours. This means you initiate your first meal 16 hours before eating the last meal on the night before (which is easily done by skipping breakfast and lunch). Thus, ideally all eating is done within an 8 +-1 hour timeframe."

Pretty much identical to the protocol Zinczenko is promoting. It's almost inconceivable that Zinczenko wasn't aware of Martin's work as Martin's a very well known guy in the fitness/body building world. I think I first came across Martin's work on intermittent fasting back in 2008 and of course I'm nowhere near as keyed in to the fitness scene as Zinczenko, for as he himself notes,

"I've been working as a health journalist for more than half my life. You name an issue - absorption rates of minerals, causes of metabolic syndrom, funding for prostate cancer research, omega-3 versus omega-6 ratios - and if it has something to do with health or wellness, I'll usually have the background on it. I'm not the world's top expert on everything, but chances are, I know the world's top expert"

Which in the case of the The 8-Hour Diet is almost certainly Mr. Berkhan.

As far as the diet itself goes, when you get to that section suddenly there are a few more rules than simply an all-you-can-eat buffet of whatever you want for 8 hours a day. Zinczenko wants you to, at each meal or snack, eat two of his eight "Powerfoods" which include lean sources of protein, nuts, yogurt and other dairy, legumes, berries, fruit, green leafy vegetables, and whole grains. Looking at his meal plan I crunched calories. Because his recipes include calories (I wish every diet book's recipes did, kudos to Zinczenko) I crunched every day. If you follow his 7-day meal plan, you'll average 1,595 calories. From a low of 1,222 to a high of 1,805. Breakfast perplexed me some. After all breakfast is literal here - you're breaking your 16 hour fast and presumably you're rather hungry which is likely why Zinczenko notes of his,

"I tuck into my fast-breaking meal - whatever time of the day it falls in with gusto - Ditto the other major meal I have during my 8-hour eating time. But there's only so much one stomach can hold, so I make sure I plan my foods carefully",

Clearly Zinczenko is suggesting his breakfasts are rather large as, "there's only so much one stomach can hold", yet his suggested meal plan includes breakfasts that are at once incredibly low in both calories and volume. For instance he has you "tucking in with gusto" to smoothies with less than 200 calories, or to a few lonely blueberry pancakes clocking in at 315.

In the 8-Hour Diet, the conjecture, ridiculous metaphors and hyperbole, like a sweaty, red-faced, whistle-wearing, 1950s gym teacher on an overweight boy trying to climb the rope, come at you hard and heavy throughout (see, I can write that way too), but my favorite stretch had to be when Zinczenko backs up his 8-Hour Diet by means of suggesting Moses, Jesus, Buddha, and Muhammed, were big fans,

"Maybe that's why eating the 8-Hour Diet way has been popular with the great minds of the last many millennia. The scientific evidence for this diet is new, but wiser men than me have been following a similar type of eating for eons. The Big Four of religion - Moses, Jesus, Buddha, and Muhammed - all practiced and promoted fasting, and chances are they knew a thing or two more than we do."

If you read the 8-Hour Diet's reviews on Amazon you'll see quite a mixed bag with many of the negative reviews talking of the diet's lack of efficacy. Truly, if you take Zinczenko at his word and treat the diet as an eat whatever you want for 8 hours a day lose weight diet, I think you'll be disappointed. Our environment doesn't lend itself to being blindly indulgent. Single meals out can easily contain over 3,000 calories and even while eating in, if not doing the cooking and thoughtfully navigating your choices, the calories can add up incredibly quickly. And if you struggle controlling calories on the 8-Hour Diet, I'm not sure the book will be much help. While it does have a section on 100 ways to cut out the calories they include such things as, "Watch a funny YouTube video", "When a craving strikes, make a fist", "Call your Mom", "Just breathe", "Read a thriller", "Flip through old photo albums", "Play "Words with Friends"", "Chew ice", "Light up candles scented with peppermint, banana, green apple and vanilla", "Watch traffic on the highway", and my favorite by far, "Clean the toilet".

To sum up, there is indeed some young science, much of it still theoretical, behind fasting as a means to improve health, and some studies too suggesting it may be useful in weight management. That said, I've yet to see any long term studies which given the fact that fasting is in and of itself, for many (though certainly not all), a form of suffering, I wonder about the attrition rate over time for fasting approaches. If you're interested in trying a 16 hour a day fasting style diet certainly you can pick up The 8-Hour Diet....or you could head over to Martin Berkhan's Leangains and read through the reams of freely available information he's been posting on his 8 hour diet since 2007, and a good place to start would be his Leangains Guide.