The diet and weight loss chronicles received a retro boost recently with the publication of a study in the Journal of the American Medical Association. The A to Z weight loss Study randomized willing participants to one of four diets: Atkins, Zone, Ornish or LEARN.
Studies such as this, examining the most effective method of losing weight, have been plagued with methodological and patient related issues. High dropout rates, poor compliance with diet protocols and short duration of study have left the conclusions drawn from these studies nebulous at best. Layer that with popular diet authors espousing the virtues of low carbs, zone eating, eliminating refined sugar, or in the case of the American Heart Association, eating by the dictates of the No Fad Diet, and the public becomes confused.
So to further the confusion and nebulousness, we have the A to Z weight loss Study. The A to Z Weight loss Study published in JAMA compared the Atkins, Zone, Ornish and LEARN diets in premenopausal women. Naturally media-reported ultra-short sound-bite analysis declared the Atkins diet the winner. The Atkins Diet, you ask in dismay? Didn’t they go away after bankruptcy and weren’t the virtues of this diet debunked? Apparently not.
Let’s look at the study. The endpoints of the study examined weight loss, changes in lipid profiles (total, LDL, HDL cholesterol and triglycerides) as well as changes in waist to hip ratio, % body fat and a few other variables. The participants were generally obese women in the age range 25 to 50 years with a BMI range of 27 to 40 (average in the 31 to 32 range) followed for 12 months with frequent follow-up visits. The interesting point of this study is that it addressed some of the prior problems plaguing similar weight loss studies. Lets look at them individually:
Drop out rate: The study randomized 311 participants to one of four diet groups listed above. Atkins had 77, Zone 79, LEARN 79 and Ornish 76. Of the four diet groups the number of dropouts respectively were 9, 18, 18, 17 which isn’t a terribly bad drop out rate.
Regression to a regular diet: This is where the low carbohydrate dieters start eating higher percentages of carbs and likewise the low fat dieters eat more fat. In short, the dieters regress to a normal diet and give up the basic principles of the diet. Again, in this study, regression to a normal diet resulted, but wasn't terribly bad.
The result: Much to the chagrin of the scientific world, (and the authors of the losing diet plans)the Atkins protocol won the horse race. Those on the Atkins diet lost a significantly greater percent of BMI, had lower % body fat, and had significantly lower triglycerides with no change in LDL cholesterol. The authors of the study concluded there were no adverse metabolic effects for those women following the Atkins diet regimen.
As Sir William Bragg (1862-1942) was quoted as saying, “The important thing in science is not so much to obtain new facts as to discover new ways of thinking about them.” What if, after digesting Sir Williams quote, the important thing about diet, health and weight loss wasn’t so much what you ate, but how much of it you ate (in terms of calories)? More commentary later.
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A Point of View
Modern Western society is awash in a sea of food affluence. For many of us, from the moment we arise in the morning to the time we fall asleep at night, the one rhythmic pattern occurring daily with anticipated consistency is food intake—and in many cases very high quality food intake. Even the smallest of excess calories consumed daily translates over time to excess energy being stored as fat in adipose tissue.
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Overeating has become the symptom of a cultural disease associated with conditioned food intake, not a mystical physiologic process involving genes gone wild. From one diet manual to the next, the book offerings to navigate this mess are fancied up versions of the same old thing, eventually returning the dieter to a conditioned system of eating behavior. The contention of this blog, is it's time to get off the merry-go-round of dieting and learn the ABC's of basic nutritional science. Teach your children what they need to know to navigate the gauntlet of foods in the 21st century. We encourage any experts in the field to contribute.
3 comments:
WG, this was indeed fascinating, but equally the key limitation, as also admitted by the investigators, was that Atkins was the best weight LOSS diet, but since it was temporally limited, they could not be so confident of its long-term effects (esp. given its emphasis on proteins and fats). In other words, the limitation relating to 'regression to a regular diet' remains a considerable one. Unless of course they have a plan to track the effects of this regression - in a controlled comparison with those who did not regress - over the next 5, 10, 15 years and publish more work on it.
Shefaly: Thanks for your interest. Although regression to the usual diet remains a problem, what impact do studies like these have on the average person reading tabloid nutrition news? The answer is it perpetuates the myth that an individual can pick up a book at the local bookseller and follow a plan for a few weeks or in this case up to a year, and lose weight. Which is a perfectly ridiculous proposal but still a template for most citizens.
Thanks, WG.
It will be interesting to see if the Atkins diet (proxy for which may be sales of eggs and meat) has gone up in popularity since this study was publicised (I say 'publicised' and not 'published' simply to see its effect outside academia).
Keeping the weight off remains the big challenge of course, as listening again to my research interview shows. Every single expert - in the UK and in the US - said the same thing. The Holy Grail of obesity I suppose..
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