If you’re like me, you exercise for several reasons: it makes you feel better, it’s good for your cardiovascular system, and it helps you lose or maintain the weight that no matter how virtuous we think we are each additional year seems to lard on. Unfortunately, according to a recent piece in New York magazine, the whole losing weight by exercising thing may not be true. What??? Say it ain’t so.
The author of the piece, Gary Taubes, who wrote the new book, "Good Calories, Bad Calories: Challenging the Conventional Wisdom on Diet, Weight Control, and Disease," says that while the new joint guidelines for physical activity and health published by the American Heart Association and the American College of Sports Medicine "suggest that 30 minutes of moderate physical activity five days a week is necessary to promote and maintain health," they pointedly didn’t say that "that more physical activity will lead us to lose weight.
"Indeed, the best they could say about the relationship between fat and exercise was this: '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 how have low energy expenditures. So far, data to support this hypothesis are not particularly compelling.'"
Taubes argues that the one thing certain about exercise is that it makes us hungry and so when we burn more calories, we also end up consuming more. The most comprehensive study of the relationship between exercise and weight loss, an analysis in 2000 by two Finnish researchers of data on the subject over the last 20 years, discovered, very discouragingly, that even successful dieters who were trying to maintain weight loss eventually gained it back, regardless of whether or not they exercised.
OK, shoot me now.
Fortunately, Taubes gave me some hope. According to him, "because insulin determines fat accumulation, it’s quite possible that we get fat not because we eat too much or exercise too little but because we secrete too much insulin or because our insulin levels remain elevated far longer that might be ideal."
So what’s that mean in practical terms? George Cahill Jr., a retired Harvard professor of medicine and an expert in insulin secretion, suggests that the consumption of easily digestible carbohydrates and sugars (like those found in soda pop and potatoes, pasta, rice, donuts and beer) are fattening us up because they spike our insulin levels, which in turn causes our tissues to retain fat.
I get it. If I maintain a more even-keeled level of blood sugar, by eating throughout the day small amounts of protein – cheese, eggs, yogurt - with small amounts of complex carbohydrates – fruits, beans, whole grains - then my insulin levels won’t spike. And with this new approach, if I balance what I eat with a reasonable amount of exercise, I should be able to maintain my weight.
On the other hand, I confess that my visits to the gym have fallen off sharply since I read this news that exercise won’t by itself keep me trim. In the game of aging and staying fit, there are no silver bullets.