Weight loss and exercise

Back to the battle of the bulge and the series of articles that got me going on that subject. The first part in the series focused on whether exercise would help you lose weight.

Here is how the author introduces the subject (1):

"It′s such a widely accepted idea it′s virtually dieting dogma, a belief pushed with almost religious zeal: You can′t lose weight without exercising more."

and

"We have been taught that exercise is a surefire path to weight loss. But controversy is growing over whether working out to lose weight can be an exercise in futility. At issue is whether the amount of exercise needed to make a meaningful impact is unrealistic and whether gluttony, and not sluggishness, is where we should be focusing our efforts."

So, does exercise help you lose weight? As the introduction implies, the answer seems to be no. This is also the conclusion of a 2009 Time Magazine article (2) that ruffled quite a few feathers. The author of that piece quotes an exercise expert as saying that "In general, for weight loss, exercise is pretty useless … The common belief that physical activity can counteract rising rates of obesity is based on a belief rather than on solid scientific evidence.".

Why doesn′t exercise lead to weight loss? The typical explanation is that people don′t work out long enough or intensely enough (1):

"The amount of exercise needed to cause significant weight loss is more than most free-living individuals are capable of undertaking, and that is particularly true for the obese".

"You need a lot of exercise, and a lot of time, to make a 200, 300, 400 calorie deficit whereas you can easily make a 1,000 calorie deficit by cutting down your intake "

Of course, not everyone agrees that exercising to lose weight is futile, even in the face of evidence to the contrary. Here is my favourite quote — it demonstrates so beautifully just how misguided expert advice can be (1):

"[It] makes no difference to the human body whether it sheds calories via eating less or exercising more. The end result is the same: weight is lost."

This statement is only partially right. It really doesn′t seem to matter whether we shed calories by eating less or exercising more; the result appears to be the same all right. Unfortunately, the outcome isn′t weight loss, but rather a failure to lose weight.

What is wrong with the idea that all you have to do is create an energy deficit and you′ll lose weight?

Suppose you are overweight or obese. If you′re not losing weight this has to mean that all your energy needs are met by the food you eat. You now start a regular exercise routine hoping to lose weight, i.e. to burn some of your stored fat. Question: Why should your exercise fuel come from your adipose tissue, when all your other metabolic needs are met by food?

For exercise to lead to weight loss it would have to do more than just create an energy deficit. Exercise would have to draw on the fat reserves stored in the body′s adipose tissue, without replenishing those stores afterwards.

Just because exercise doesn′t help you lose weight, this doesn′t mean it is useless. Physical activity has many health benefits, such as increased cardiovascular fitness and insulin sensitivity, lower blood pressure, and improved mental health and cognitive ability. It just doesn′t seem to help you lose weight.

Sources:
  1. Sharon Kirkey. Exercise alone doesn′t cut it. Canwest News Service March 6, 2010.
    http://www.timescolonist.com/health/battle+cultural+epidemic/2660423/Exercise+alone+doesn/2649284/story.html
  2. John Cloud. Why exercise won′t make you thin. Time Magazine August 9, 2009.
    http://www.time.com/time/printout/0,8816,1914857,00.html
Posted by Helmut Beierbeck at 3/14/2011 2:26 PM
Categories: weight loss
 

What did you think of this article?




Trackbacks
Trackback specific URL for this post
  • No trackbacks exist for this post.
Comments
Display comments as (Linear | Threaded)

Leave a comment

Submitted comments are subject to moderation before being displayed.

 Name

 Email (will not be published)

 Website

Your comment is 0 characters limited to 3000 characters.