Keeping a Food Diary Doubles Weight Loss, Says Study

Losing weight and keeping it off remains at the top of the list of difficult challenges for most people in America, with about 65% of adults in this country currently overweight or obese. Research shows that between 20% and 40% of Americans are currently trying to lose weight… sadly, without much success. Now a new study from the Kaiser Permanente Center for Health Research in Portland, Oregon, has identified what weight strategies appear to be most highly associated with successful weight loss. One of the most effective is also one of the easiest to do.


Researchers enrolled 1,685 overweight or obese adults in a weight loss program that included 20 group training sessions over six months. During that time, participants were given instructions on how to follow a calorically appropriate diet, low in sodium and high in fruits and vegetables and containing low-fat dairy. According to Jack Hollis, PhD, lead researcher, participants were also instructed to engage in 30 minutes of moderate exercise each day, including a 30-minute brisk walk held during the weekly group meeting. They were also taught how to keep a food diary, in which they were to write down everything they consumed, and were strongly encouraged to do so.

After six months, 69% of the participants had lost at least 8.8 pounds of body weight, an amount considered to be clinically significant. The mean amount lost was 13 pounds after 20 weeks. Researchers then analyzed what behaviors were most correlated with success.

A particularly striking finding was that participants who kept daily records of what they ate lost twice as much weight as those who kept no records. “The act of writing down what you eat makes you more conscious of what you’re eating,” Dr. Hollis told me, calling it “a powerful self-management tool.” Other behaviors that correlated with weight-loss success were number of minutes per week spent exercising and how many group meetings a member attended.


Dr. Hollis offered some tips for those interested in getting this good habit going…

  • Measure, as much as possible. Use tablespoons, measuring cups or a food scale to get an approximation of quantity. In the study, the participants were taught to estimate using common visual reference points — for instance, a serving of mashed potatoes the size of a computer mouse is four ounces, while a three-ounce portion of chicken, fish or steak is about the size of a deck of cards.
  • Estimate how many calories you’re eating. Use a calorie book or look up your food online. This is easier than it sounds, says Dr. Hollis, since most people eat the same foods often.
  • Simple notes are fine. Keeping a food diary doesn’t have to mean lugging around a notebook — you can jot intake down on a Post-it and it will still help you be more attentive to what you’re eating.
  • If you miss a day… start again. Those who kept the most consistent food records lost the most weight in the study, but even those who kept some records regularly lost more than those who kept none.