Long ago I had one of those "choose-your-own adventure" books based on a James Bond movie, and I made bad choices; the poor British spy kept getting consumed in a vat of molten lava, impaled on a bunch of spiky things or became an appetizer for saltwater crocodiles.
But when it comes to the exercise-then-choose-your-food adventure that that I've lived my whole life, however, I have a far better track record.
Do you know the three mealtime words that can cripple weight loss? "Because I exercised," says my friend Dr. Yoni Freedhoff, an obesity researcher in Ottawa, Ontario.
Burning off 300 calories on an elliptical trainer then rewarding your efforts with a 500-calorie piece of cheesecake is just bad math. That's the choice that leads to spiky, overweight crocodiles in lava. The other choice is realizing that burning calories is the least important thing exercise does. This choice takes advantage of the cognitive-boosting effects of physical activity to resist food rewards and make healthier choices that fuel performance.
Another friend of mine, obesity researcher Dr. Sue Pedersen, a specialist in endocrinology and metabolism in Calgary, Alberta, told me, "The bottom line is that weight loss is 90 percent about diet."
You cannot out-exercise a bad diet. So go ahead, choose your own adventure.
Adventure 1: 'I exercise, so I earned this treat.'
So we're a few months into this New Year, and you've resolved to get in shape and lose weight. You're going to the gym — walking, jogging , swimming, cycling or whatever. After a good workout, you think, "I'm exercising now. I deserve this treat."
This adventure is called the "reward mentality."
Because you exercised, as Freedhoff explained, you believe you have leeway in terms of dietary choices. You can have seconds, drink extra booze, care less about what you consume.
The problem, professor Eric Ravussin, of the Pennington Biomedical Research Center in Louisiana, explained to me, is that most obese people are incapable — both physiologically and psychologically — of the type of physical activity required to make significant contributions to the daily caloric deficits required to achieve significant weight loss. They tend to overestimate just how many calories they burn via exercise then overcompensate with food reward.
As I mentioned, it's bad math, but it happens all the time. People choose this adventure and the result is numerous studies showing exercise alone doesn't lead to weight loss.
I admit to choosing this adventure on summer vacation. During this time I run many miles a day, paddle long and hard in a sea kayak, play actively with my children and even do some swimming. I probably exercise harder during vacation than any other time of year. I also let my diet go to hell. Additionally: muchas cervezas.
And I gain weight. It's only when I'm back home and once again restraining my food choices that the pounds drop back off. When not on vacation, I'm living. …
Adventure 2: 'I exercise, so I need healthy fuel.'
Because weight loss is simple caloric restriction, it can be done easily by eating less, but in an environment with 24/7 McDonald's, rapid pizza delivery and doughnuts at meetings, it's hard to resist the constant call of the cookie, cream puff or cheeseburger.
"Exercise is a critical component of weight loss and weight maintenance," Dr. Miguel Alonso-Alonso, a Harvard neurologist and specialist in how exercise affects the brain, told me. "We know that. It's a fact."
First off, stress eating is common, and in an earlier column I showed how exercise is one of the most powerful tools available for reducing stress. Beyond that, Alonso-Alonso says, it boosts your ability to stick to a plan. "Physical activity and eating behavior are connected in the brain at the cognitive level. It's the same mental processes."
Alonso-Alonso explained we use goal-oriented systems in our brains to suppress those immediate impulses to eat junk food. "The resources for goal-oriented eating behavior are greatly enhanced via physical activity," he said. "Exercise improves eating behavior through brain and cognitive changes."
Healthy eating involves sticking to a plan. At the cognitive level, exercise makes you better at sticking to a plan by enhancing "executive function" and decision-making ability. Every time you eat, it's decision plus higher executive function equals better decisions. Oh, and according to Brian Wansink, a professor of consumer behavior and nutritional sciences at Cornell University, we make more than 200 decisions about food every day.