“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.
To find out why, I read through more than 60 studies on exercise and weight loss. I also spoke to nine leading exercise, nutrition, and obesity researchers. Here’s what I learned.