We all know that a combination of diet and exercise is important to good health and psychological well-being. If we only diet, we don’t get the cardiovascular and psychological benefits of exercise, and we run the risk of lowering our metabolic rate, making weight loss even harder. If we only exercise without watching our intake, the exercise is likely to make us hungry. We might not gain weight, but it’s unlikely we’ll lose any.
I’ve often felt a bit guilty about letting Jenny do most of the work for my weight loss and maintenance. I am a fairly sedentary person who spends quite a few hours in front of the computer. Other than walking around campus and pacing in the front of my classroom, the only exercise I get is my afternoon walks with Mr. F to our favorite coffee shop, the Nautical Bean. The round trip is about 2 miles. Ho hum. Better than nothing, but we walked it plenty of times without losing an ounce. We walk so regularly that some of our neighbors ask us for our “real names,” because they refer to us as “the Walkers.” Nonetheless, we walked the same amount when Mr. F was 100 lbs heavier and I was 80 lbs heavier, and none of that weight budged. We’re afraid that people who have seen us lose weight over the past 2 years will think that all we’re doing is walking. Okay, if it gets them moving, that’s great, but they’ll be disappointed with the results if that’s all they do.
Some of my guilt was reduced by a recent article by Derek M. Huffman and his colleagues . These researchers compared the health and longevity of mice that exercised and mice with caloric restriction. Although exercise does a lot of good, by itself, it does not extend lifespan, at least for mice. In contrast, restricting calories produced a unique set of benefits that did not occur in the mice that exercised without caloric restriction. The caloric restriction used in this study was mild–only 9% and 18% in different groups. That’s equivalent to 225-450 calories for a person eating 2500 calories per day, like passing up dessert. In many rodent caloric restriction studies, the animals eat only about 65% of their normal food, or 875 fewer calories for a person normally eating 2500 calories. That’s probably okay when you’re trying to lose weight (Jenny put me on 1200 calories and I lost about 2 lbs per week), but you can’t keep it up indefinitely without becoming anorexic.
These are mice and we are people, but Huffman et al. do remind us that “fit and fat” is better than just fat, but “fit and thin” is probably a better goal. And yes, it is my goal to get out on the stairmaster more often.
1. Huffman, D.M., Moellering, D.R., Grizzle, W.E., Stockard, C.R., Johnson, M.S., & Nagy, T.R. (2008). Effect of exercise and calorie restriction on biomarkers of aging in mice. American Journal of Physiology–Regulatory, Integrative and Comparative Physiology, 294.