You may have read one of the many articles that were released recently reporting about a study by the Pennington Biomedical Research Center. Some of the news pieces were entitled "No need to diet and exercise to lose weight" or "Exercise Doesn't Matter For Weight Loss".
Both the study itself and the way its findings have been presented in the media are misleading. I wanted to expose the half truths that are right now being presented as facts. My problems with the study are expressed in the following email I wrote to the lead researcher:
I recently read your study entitled “Effect of calorie restriction with or without exercise on body composition and fat distribution” and much of the subsequent reporting on various news outlets about the study.
Although it may not have been your intent, you have done a great disservice to the public. Your study is was in part meant to determine the effect of “exercise” on weight loss, fat loss and body composition. Yet your definition for what qualifies as exercise is not at all representative of what today’s public at large accepts as exercise, nor representative of what the fitness industry has long preached to attain the goals of fat loss and improved body composition.
It is well known that concern for lean muscle mass is equal to concern for a caloric deficit in the quest to lose body fat. And concern for muscle as it pertains to exercise is the most important factor in changing body composition (body fat to lean tissue ratio). In other words, exercise designed to induce muscle hypertrophy (resistance exercise) is the most important factor in a program of exercise designed to change a person’s ratio of body fat to total body weight.
It is also well known that the addition of lean body mass raises a person’s Basal Metabolic Rate – the ability to burn calories even at rest.
So why did your study not include exercise designed to increase lean muscle mass, knowing how crucial it is to a regimen designed to improve body composition? And worse why did you not represent your study as what it was - a study of aerobic activity, not of “exercise” as today’s fitness industry and public at large defines it?
For a subject who wanted to improve their body composition, lower their body fat percentage, and improve their ability to keep fat off, no educated exercise physiologist or certified fitness trainer would have simply prescribed - “Treadmill, exercise bike, stairmaster … your choice.” But that’s what you did, and you didn’t make it a point represent it that way.
The public at large is simply not going to read the full report. They’re going to read what the news reports about it. And what the news is reporting about it that “exercise” is no more effective at changing body composition than simply reducing caloric intake. This is not true! Resistance exercise, designed to induce lean muscle gains in combination with a caloric deficit does change body composition! aerobic activity alone (your version of “exercise”) does not!
Age and inactivity result in lean muscle loss. So does excessive aerobic exercise without any resistance exercise. Lean muscle loss results in a lowered metabolic rate. Lowered metabolic rate means it is harder to keep the fat off. This means continually declining calorie restriction in order to keep pace. This is not the way to healthy, long term fat loss. Yet the way you are representing your findings will simply encourage the public to restrict calories more and exercise less.
I assume that you and your colleagues are all very smart people. So I have to also assume that you are not ignorant of resistance exercise and its benefits. I can only surmise that your design of this study and reporting of its findings was meant to mislead the public.
After all, it is the mission of your organization to promote nutrition and preventative medicine, not exercise. People who have been empowered by a true fitness lifestyle, (one that stresses aerobic activity, proper nutrition AND concern for muscle), have less need for medicines. They have healthier body compositions and less need for calorie restrictive diets (or nutritionists for that matter).
I’m sickened. If you have any conscience at all, you’ll re-release your findings to the press and entitle it “Effect of calorie restriction with or without aerobic exercise on body composition and fat distribution”, and furthermore add the word “aerobic” before every instance of the word “exercise”. That is the true nature of your study.
I am encouraging all fitness professionals to respond at once through the various media outlets to put this study in its proper perspective. The way it has been reported on this far will have detrimental effects to the health of the public at large.