“I’m going to make you work hard,” a blonde and perfectly muscled fitness instructor screamed at me in a recent spinning class, “so you can have that second drink at happy hour!”
At the end of the 45-minute workout, my body was dripping with sweat. I felt like I had worked really, really hard. And according to my bike, I had burned more than 700 calories. Surely I had earned an extra margarita.
The spinning instructor was echoing a message we’ve been getting for years: As long as you get on that bike or treadmill, you can keep indulging — and still lose weight. It’s been reinforced by fitness gurus, celebrities, food and beverage companies like PepsiCo and Coca-Cola, and even public-health officials, doctors, and the first lady of the United States. Countless gym memberships, fitness tracking devices, sports drinks, and workout videos have been sold on this promise.
There’s just one problem: This message is not only wrong, it’s leading us astray in our fight against obesity.
It’s interesting how wrong this thinking is, that exercise will make you lose weight. The multi-billion dollar diet industry is one of the biggest scams out there, constantly churning out new diet books, leading people to yo-yo as they lose weight, then gain it back.
One of the interesting points in the article is just how little of our caloric expenditure comes from activity.
There are three main components to energy expenditure, Kravitz explained: 1) basal metabolic rate, or the energy used for basic functioning when the body is at rest; 2) the energy used to break down food; and 3) the energy used in physical activity.
We have no control over our basal metabolic rate, but it’s our biggest energy hog. “It’s generally accepted that for most people, the basal metabolic rate accounts for 60 to 80 percent of total energy expenditure,” Kravitz said. Digesting food accounts for about 10 percent.
That leaves only 10 to 30 percent for physical activity, of which exercise is only a subset.
Exercise is certainly important; it has many health benefits. It just doesn’t help you lose much weight, in part because your body’s metabolism adjusts to your activity in order to maintain your weight.
I still wonder about the obesity epidemic. It’s not entirely about eating more; there aren’t that many people who necessarily started eating more and then became obese. Is obesity an inflammatory disease? Is our gut bacteria to blame? Is it caused by exposure to chemicals? I find that fact that obesity took off in the 1980s to be interesting, and wonder if it has something to do with environmental factors, such as new plastics that have been used since then, many of which are known to be endocrine disrupters.