There's a reason so many doctors and nutritionists recommend keeping a food diary when you're trying to lose weight: It actually appears to work. The case for food diaries (or food records or journals) got a little stronger today, when weight-loss researchers reported that a large, multicenter study suggests that tracking what goes in your mouth can double the amount of weight lost. The findings were part of a weight-loss maintenance trial whose initial results were reported in March. After analyzing the data on weight loss to see which factors made a difference, researchers concluded that the more days a person kept a careful record, the more weight he or she lost. (Attending more weekly support group sessions also helped). Here's why keeping a diary is so powerful:
It's simple. No fancy machines required; just record what you eat on paper or using an online record. "The trick is to write down everything you eat or drink that has calories," says Victor Stevens, a researcher at Kaiser Permanente's Center for Health Research and coauthor of the study released today, which appears in the American Journal of Preventive Medicine. That's easy enough with labeled foods but gets harder when you're dining out or are eating an unfamiliar food. Try online calorie databases like CalorieKing.com, and watch the serving sizes—here's a good source of info on estimating what, say, an ounce of bread looks like. You'll probably still underestimate your daily intake, says Thomas Wadden, director of the Center for Weight Loss and Eating Disorders at the University of Pennsylvania School of Medicine, but you'll very likely come closer than someone who isn't keeping a food record.
It's eye opening. In fact, some people will be so shocked at how many calories are in their thrice-daily Coke that the "aha" moment will make going on an actual diet unnecessary. Being forced to be aware of what you're eating can often be enough to help people drop weight, says Wadden.
It helps you track your progress. Use the diary as a way to make adjustments throughout the day and to gauge how much exercise you need to hit a certain calorie count, advises Holly Wyatt, a physician and researcher at the Center for Human Nutrition at the University of Colorado Health Sciences Center. "If I eat three cups of fries, I know that I ate a lot and can cut back at the next meal," says Francis Tacotaco, a 38-year-old skilled nursing assistant from Richmond, Calif., who used a food diary as part of a weight-loss program at Kaiser. He's lost 21 pounds so far and wants to drop more.
You're accountable to someone. Supervised weight-loss programs often require participants to turn in their food diaries to nutritionists or doctors, which may make you think twice before giving in to temptation. "I've seen it all," says Stevens. "One gallon of vanilla ice cream, three pizzas, and a gallon of milk. My experience is that the people who have the courage to write it down tend to do pretty well," even if what they're writing down amounts to a lot of food, he says. If you're not part of a program, you can team up with a friend and swap food diaries once a week to keep each other in line. And many people find it's enough to be accountable to themselves. "You won't put that second cookie in your mouth because you don't want to see it in your food record," says Stevens.
After the extra poundage is gone, many people continue to use a diary to keep themselves honest. About 50 percent of participants in the National Weight Control Registry (which tracks the habits and practices of weight-loss maintainers) report they use some kind of self-monitoring, such as a food diary, says Wyatt. Some people may keep a diary on the weekend only, when they tend to eat more; others just record dinner, which usually varies more than breakfast and lunch, says Wadden. It's a habit you can benefit from for a lifetime.