Sunday, August 12, 2012

Diet or Exercise?

I have heard a lot of discussion lately about a recent study regarding physical activity, metabolism, and weight. Researchers studied a group of 30 hunter-gatherers in an effort to determine how their physical activity affected their metabolisms. The basic finding was that their metabolisms adjusted to their high level of activity and low calorie consumption. They did not burn significantly more calories daily than most people living in developed societies who sit at a desk all day.

What some people are taking away from this is that exercise is not an effective tool for weight loss; that only what we eat makes a difference. THIS IS NOT TRUE!!! Even the authors of the study stated that, "Physical activity has important, positive effects on health, and increased physical activity has been shown to play an important role in weight loss and weight-maintenance programs."

If you are trying to lose weight, you should not be asking the question, "should I exercise or change my eating habits?" BOTH are important for weight management. One of my favorite quotes is, "You can't compete with what you eat." You can work your butt off in Zumba with me but if you leave and drink 2 margaritas you've probably just consumed more calories than you burned in class. Does that mean that class was a waste of time? Does it mean that you can't ever have a margarita again without feeling guilty? Of course not.

When we think about the food/exercise balance, we shouldn't think about exercise as a way to compensate for what we eat. In Zumba class one day, I really pushed myself hard. About halfway through class, one of the students asked, "What did you eat this weekend that you feel so guilty about?" This question made me laugh because my intensity wasn't about "burning off" anything I'd eaten, it was about working harder as part of a challenge I had set for myself. But there have been many times in my life where that is exactly what would have been going on. The sad thing is that it was never effective. I would severely restrict my diet, feel deprived, engage in gargantuan binges, then exercise excessively to try to "make up" for what I had eaten. But that was impossible. While I was engaging in that behavior I was overweight. And my weight fluctuated all the time. And I hated my body. And I felt like a total failure. Even long, hard exercise sessions couldn't burn the number of calories I was eating in those binges. And because the focus of those workouts was guilty feelings, I stopped enjoying exercise.

I saw a demonstration of this kind of thinking on a weight loss reality show once. A participant was struggling to change his eating habits and was still engaging in behaviors like bingeing on Oreos. The trainer had him hold two Oreo cookies in his hands as he walked up and down a flight of stairs. He wore a device that measured the calories he was expending and she had him keep going until he had burned the same number of calories as the two Oreos contained. He was at it for a LONG time! He said he had learned a valuable lesson and was going to ditch the Oreos. But I don't think that's the lesson we need. We have to be aware of the calories in, calories out equation, but we can't think of activity solely as a way to burn off those Oreos. We can eat the Oreos in moderation as long as we fit them into our overall target calorie consumption. And exercise should not be punishment or compensation for what we eat. If you're eating a generally healthy diet with a calorie intake that is less than your expenditure, you should be able to eat a couple of cookies here and there and still lose weight. 

A related note we can take from the Hunter-Gatherer study is that exercise can't be a green light to eat whatever we want. Part of the metabolism equation for the study participants was their very low calorie consumption. I have a new Zumba student who mentioned that since she started exercising more, and harder, she felt hungry, "ALL the time!". That is a pretty common experience. I cautioned her to eat when she felt hungry but to try to be sure that the foods she chose were healthy and nutritious and to keep an eye on the overall amount she was eating. It is awful to work hard at exercise and feel like we are not getting the results we're looking for. So really, anyone looking to achieve or maintain a healthy weight should engage in a consistent exercise routine AND have good eating habits.

The hunter-gatherer study reinforced that our bodies seek homeostasis. If you exercise, your body will adapt. If you cut your food consumption, your body will adapt. Our bodies are amazing, complicated machines. I will explore adaptation more in future posts. For now, eat healthy foods because they are yummy and they fuel your body. Exercise because it is good for you in many, many ways (and can be a lot of fun!).

So this week's challenge is to look critically at the way you think about the food/exercise equation. Do you need to change your thinking about why you eat the food you eat? About the feelings you have after you eat? About why you exercise? If so, now's a great time to practice! Permanent behavior change requires changing our thinking. Write down those negative thoughts and feelings and try to rewrite them with a healthier view. You can even post them here and I can help!

To read the entire article on the hunter-gatherer study, click here

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