There's been some discouraging news about the standard prescription for weight loss—diet and exercise—lately. A few weeks ago, I wrote about a study that compared the low-carb, low-fat, and Mediterranean diet, and found that none worked screamingly well. Now comes another study showing that of a group of about 200 women who were given advantages most dieters don't have, like free group meetings, telephone support, and even a home treadmill, only about a quarter were able to keep off 10 percent of their body weight after two years. And those who did keep it off exercised about 275 minutes a week, which translates to 40 minutes every day or 55 minutes five days a week. I talked to study coauthor John Jakicic, from the Physical Activity and Weight Management Research Center at the University of Pittsburgh, about what the research means for dieters.
For keeping weight off, how important is exercise?
Short term, everyone [in the study] seemed to do well as long as they exercised. To sustain weight loss, exercise becomes more and more important. The best predictor of who kept the weight off was physical activity, but those people were still being pretty vigilant about their diets.
How hard do you have to exercise?
As long as the activity is at least moderate in intensity [like a brisk walk], it becomes a matter of preference. It comes down to the number of calories burned. The advantage to going a little harder is that you can go for a shorter period of time. But ultimately, it's calories, calories, calories.
So what's the strategy to adopt?
Everyone could benefit from more activity. If that's helping to control your body weight, great. If not, you may need to ramp it up. I firmly believe that somewhere between 30 to 60 minutes a day can help people keep it off. If you're really diligent with your diet, you may be able to get away with 30 minutes a day. If you are a little more lax, with room for errors, it will be closer to 60 minutes.
That sounds like a lot, for most people.
People will say, "My gosh, I can't find time to do anything, so how can I find time to do that?" Well, you have to start somewhere and work your way up to this level. It may be that for some people we say: Carve out this time to exercise, or you're really going to struggle to lose weight.
For more: I wrote a few years ago about how much exercise to get, depending on your health goals, and about overcoming various excuses for not exercising. And here's an article on how to increase your daily calorie burn without a formal exercise program.