Bryan Marcel: Do You Need To Eat Less And Exercise More?

In order to lose weight a person should reduce their calories and increase the amount of exercise that they do.  After all, the reason that we Americans are fat is because we eat too much and exercise too little.  Right?  Wrong.  In previous posts I have discussed the myth of calories and calorie reduction.  Today I want to address the myth that exercise is required to lose weight. Before you start to send me e-mail, please allow me to state my position.  I am a firm believer in being active.  This includes regular exercise.  There are numerous benefits to exercise.  Better over-all health, reduced body fat, better mood, better cognitive skills, better sleep, better self image, increased confidence and damn it makes you look good naked.  But as far as exercise being required for weight loss, it isn't.

The idea that exercise is required to lose weight is actually fairly new.  Back in the 1960's doctors advised against exercise for weight loss. Today it is considered essential.  The Center for Disease Control (CDC) now recommends 150 minutes of exercise a week for adults and an hour a day for children.  That's a complete course reversal in fifty years. Where has exercise gotten us?  Let’s look at the numbers. First, let’s look at obesity rates.  Since 1980 the obesity rates for adults have doubled and the obesity rates for children have tripled.  Next, let’s look at the number of people who exercise.  In 1991, 20 million people belonged to 14,000 health clubs.  In 2006, 42 million people belonged to 28,000 health clubs.  The number of people under the age of 18 that joined health clubs doubled from 1987-2002.  So to make sense of this, the number of people who joined health clubs doubled, the number of health clubs also doubled, but so did the adult obesity rate.  The number of children who joined health clubs doubled, but their obesity rate tripled.  Something must be missing, because the numbers just don't make sense.

People tell me all the time that when they used to exercise they lost weight and when they stopped they gained it back.  They credit the exercise for their weight loss. That is understandable.  Exercising is hard.  You would like to think that since you did all of that hard work that your reward was the weight loss.  I always ask if they found that when they were exercising that they paid more attention to what they were eating and drinking.  The answer is always, yes. I try to gently (I must admit, and my editor reminds me, that I'm not too good at being gentle) suggest that maybe it was the awareness of their diet that led to the weight loss and not the exercise.

But, most people insist that it was the exercise. They tell me how it helped them lose weight and increased the rate of their metabolism.  It's feels good to believe that, but unfortunately it just isn't completely true.

In 2007 the American Heart Association and American College of Sports Medicine published joint guidelines for physical activity and health.  They suggest that 30 minutes of physical activity 5 days a week is required to “promote and maintain health”, but they never say that more will have any benefit beyond “maintaining health”.  They continue, “Few reliable data are available on the relative contributions to this obesity epidemic by energy intake and energy expenditure”.  So there isn't any data suggesting that exercising more and eating fewer calories will promote weight loss. “While more information is gathered on the varied (my emphasis) causes of obesity, it seems vitally important for public health efforts to address both energy expenditure and energy intake”. “It is reasonable to assume that persons with relatively high daily energy expenditures would be less likely to gain weight over time, compared with those who have low energy expenditures.  So far, data to support this hypothesis are not particularly compelling”. Wow!  They are going to stick with and continue to promote the status quo of “eat less and exercise more” even though there is still no scientific evidence to back it up.  What a disservice to the American public.

So what would happen if you took four groups of women and gave each group a daily exercise requirement such as what the CDC recommends?  How much weight would they lose in 24 weeks?  Well, that’s what Timothy Church wanted to know when he and his colleges ran this study . They took four groups of women and assigned three of them a daily exercise regimen.  The groups were assigned a set amount of time to exercise and were instructed to make no dietary changes.  One group was not to exercise at all.  The other three were to exercise 72, 136 and 194 minutes per week respectively.  In each group some lost weight.  Some gained weight.  And some stayed the same.  As a group, the non-exercisers lost 2 pounds in 6 months.  Out of the three exercise groups the most weight lost came from the group doing 136 minutes a week of exercise. They lost on average 4.6 pounds.  That's 54 hours (136 minutes x 24 weeks) of exercise to lose 2.6 pounds more than the group that did nothing.  But more exercise has to be better, right?  The group that exercised 194 minutes a week, 77 hours in six months, lost only 3.3 pounds.  Only 1.3 pounds more than the group that did nothing at all.  Not much of a weight loss reward for all of that work.  In a 16 month University of Nebraskastudywomen aged 17-35 who exercised had no significant weight loss.  The authors’ state, “Although it is common to expect weight loss in response to exercise, our group, and others, showed no significant decrease for weight in women”.

Melbourne's Deakin University, Professor Boyd Swinburn, worked with Pennington Biomedical Research Centre to determine the cause of the U.S. obesity epidemic since 1970.  He says that, “The weight gain in American populations seems to be virtually all explained by eating more calories.  It appears that reductions in physical activity played a minimal role”.  He also emphasizes that “physical activity should be promoted because of its many other benefits, but that expectations regarding what can be achieved with exercise need to be lowered”.  I completely agree with him on that.  Where I disagree is when he says that in order “to return to the average weights of 1970's, we would need to reverse the increased food intake of about 350 calories a day for children, about one can of soft drink and a small portion of French fries”.  No!  It's not the 350 calories that we need to reduce.  It's the 58 grams of useless simple carbohydrates that the French fries and soda provide.  Ironically, if everyone did reduce the can of soda and the French fries and lost weight, credit would be given to the calorie reduction.

Many people also claim that exercising increases the rate of their metabolism.  In the January 27, 2010 issue of the American Journal of Clinical Nutrition, in a twelve week study of adolescent teens, doctors found that moderate aerobic exercise had no effect on the teen's metabolism. Many older men and women claim that the reason that they are overweight is due to a slower metabolism, that they just can’t burn fat as well as when they were younger.  In a 2007 Journal of Applied Physiology study the researchers concluded that “contrary (my emphasis) to our hypothesis, 24 hour fat oxidation was greater in older males (60-75 years old) compared with younger males (20-30 years old)”.  There went that excuse.

“We suggest that factors other than age-related changes...contribute to the (weight) gain”.  Diet perhaps?

I think it is a disservice to encourage people to eat less and exercise more.  The result will be the same overweight America.  We will continue to get fatter.  The only way to reverse this process is to break our dependence on cheap, low quality, fast, convenient, and highly processed foods. The obesity trend started to skyrocket in the 1970's.  Is it really logical to think that as a species we have survived for millions of years, but in the last 40 we started eating too much and exercising too little?  In the last forty years we have moved away from healthy whole foods and shifted to a diet of processed carbohydrate junk laden with chemicals and additives.  When I was a student pilot learning to fly an airplane my instructor told me that if I moved a switch on the airplane and something suddenly went wrong, then I had to move the switch back to its original position.  Very sound advice that actually saved my life on one occasion.  It's time to move the food switch back to its original position.

As far as exercise is concerned, I encourage everyone to be active.  Find what you like to do, whether that is a sport, walking, running, or working out.  Just do what you enjoy and stick with it.  I also encourage people to get exercise regularly.  In the studies above, the participants didn't lose weight.  What they did lose was body fat and waist circumference.  A pound of fat weighs exactly the same as a pound of muscle.  The difference is that the fat takes up a lot more space. Exercise will make you stronger and leaner.  It will make your clothes fit better.  It will make you feel better.  It will make you look better naked.  What it won't do is make you lose weight. As Professor Swinburn said, we need to lower our expectations.  If your expectations are realistic, you will be very satisfied with the results.  Me?  I love the results that exercise provides.  Now that I'm done writing this, I'm going downstairs to work out.

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