Wednesday, November 10, 2010

My Take on the 'Convenience Store Diet"

Professor Mark Haub's Convenient Store Diet has become a popular story in the media and all over the Internet.  If you haven't heard of his personal diet experiment, the Kansas State professor of nutrition lost 27 pounds of body weight over 10 weeks by consuming an 1800-Calorie diet of mostly junk food, including Twinkies, cup cakes, chips, cookies, and the like.  The stuff that will make any health nut cringe.  The reason for his experiment was to show that Calories, no matter the source, are most important for weight loss; quantity trumps quality.  Additionally, not only did he say the results support the importance of Calories in weight loss, but his health improved on the same diet implicated for most of America's health woes.

Lets take a closer look at the results of his experiment. 

Body weight vs. Body Composition:

There is good evidence to support the fact that Caloric restriction does cause weight loss.  However, the rate of weight loss varies a lot among individuals (due to various factors like activity level, body size, individual biochemistry, etc.).  Fad diets, like the grape fruit diet, lemon water and cayenne pepper cleanse, the baby food diet (thanks Tracy Anderson) will produce a loss of body weight in the short-term.  Of course, they never last and just about everyone gains the weight back.  We have intrinsic energy balance systems that regulate energy intake and expenditure over the long-term.  Professor Haub demonstrated a short-term weight loss, like tens of millions of desperate Americans every year.

The composition of weight loss is overlooked in this article and during most Calorie-restricted weight-loss programs.  In the article, it mentions that Haub's body weight dropped from 201 to 174 pounds over 10 weeks, a fairly rapid rate of weight loss (~2.7 lbs per week).  Additionally, it mentions that his starting body fat was 33.4% (classified as obese).  His body fat decreased to 24.9% over the ten weeks, which looks impressive.  However, a little, quick math shows that this is not a very desirable change in body composition.  He lost 4.2 pounds of lean body mass (of which most is skeletal muscle).   I consider that undesirable and unhealthy.  More alarming, at a body weight of 174 pounds, he is still 24.9% body fat!   One hundred-thirty pounds of lean body weight on a male body is not very vibrant or healthy.  Wait a minute, these numbers are starting to look familiar.  He has become "skinny-fat," that means his weight and body circumferences are low or "normal", but his body fat level is high, with no muscle tone.   To put things in perspective, I have helped men and women who start at this body fat level lose body fat and gain muscle mass with strength training and no dietary changes.  It is easy see improvements in body weight and body composition at this starting point, but to lose 4.2 pounds of lean body mass in the process is definitely not desirable.

Is He Healthier?

This is debatable.  He did not develop a vitamin-deficiency disease over the 10 weeks because he supplemented with a multi-vitamin.  But, the impact of our nutrition on chronic disease is complex and may not be known for years or decades.  We are still trying to figure this out.  We can easily assume that he is missing out on a lot of micronutrients, protein, phytochemicals, and antioxidants, by limiting his food choices to processed foods.   But, over 10 weeks we just don't know. 

While the article mentions that professor Haub's blood lipid profile improved, this is the only evidence he has for claim of improved health.  I would argue that these changes in blood  lipids don't prove anything about health as cholesterol and lipo-proteins don't cause heart attacks or cardiovascular disease.  Beyond the blood lipids, we know nothing of how his health changed in the short-term, let alone how his health would be affected by months and years of his Convenient Store Diet.  

In Summary

Yes, professor Haub provided more support for the importance of the quantity of Calories on weight loss.  But, weight loss in itself isn't always indicative of health or performance.   While the Convenient Store Diet was able to decrease his body weight significantly and fairly rapidly, he did lose 4.2 pounds of lean body mass.  This is very concerning and in my opinion, unhealthy.  Additionally, we don't know the effect on his long-term health, but based on the 180 million other Americans' longer-term diet experiments with processed foods, I would speculate not so good.

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