I received an email recently from a fellow dietitian with some thrilling news hot off the press. According to a just-published study about people trying to lose weight, those who consistently kept a food diary doubled the amount of weight they lost, compared to those who didn't keep a diary.

This is exciting news for those of us in the nutrition field, since this study from Kaiser Permanente is one of the longest-running weight-loss trials ever conducted, involving 1,685 overweight or obese individuals.

Participants in this weight-loss intervention attended 20 weekly sessions (90 minutes to 2 hours each) led by nutrition or behavioral counselors. During the sessions, the instructors used what's called a self-management and motivational approach, which involved talking to the participants about reducing calories and increasing their physical activity. Specifically, the participants were asked to do the following things:

• Each day, consume 500 fewer calories than they normally would
• Aim for 180 minutes of physical activity each week
• Keep a daily food log and exercise diary
• Look for opportunities to increase physical activity (e.g., park farther away at the grocery store, take the stairs vs. the elevator, etc.)
• Consume 9-12 servings of fruits and vegetables, and 2-3 servings of low-fat dairy products each day
• Reduce salt and alcohol (limit of 1 drink a day for women and 2 for men)

The weight-loss goal for the 6-month study was 4 kilograms, or 8.8 pounds.

After 6 months, participants lost an average of almost 13 pounds(!), with the most powerful predictor of weight loss being how many days a week participants kept their food diaries. Those who faithfully jotted everything down about their food consumption and exercise activities 6 days a week, lost about twice as much as those who kept food records only one day a week or less.

How can making detailed entries on a food diary most days of the week double the amount of weight a person can lose? Well, there could be several reasons, as I see it:

• Accountability. The fact that the participants knew someone would be checking their food and exercise diaries increased their dedication to keeping their caloric intake down and increasing their activity levels. Those who used their diaries only once a week might have derailed their weight loss efforts by, first, decreasing their accountability and, second, by perhaps choosing to record only their "good" eating days entries while ignoring the "bad" choices. I've had more than a few patients tell me that just knowing they were coming to see me and that I would be looking at their diaries helped them to make healthier eating choices (and I'm definitely not the kind of judgmental dietitian who yells at my patients). So, having someone to be accountable to may account for some of the diarists' success.
  
• Recognition of patterns. One of the things I tell my patients about food diaries is that these records can help to identify unhealthy eating patterns, such as eating due to anxiety, depression, stress, or lack of sleep. Once they've spotted some of these patterns and pitfalls, patients can then use behavioral techniques (such as CBT, or cognitive behavioral therapy) to restructure their thought patterns so that they stop using food to "self-medicate" or pacify their negative emotions. CBT, among other techniques, is something I use in my own practice quite successfully.
  
• Portion/calorie awareness. In addition to boosting accountability and highlighting destructive eating patterns, a diary can also help you become more aware of the amount of calories and portion sizes you're consuming. This information may be enlightening, especially when you learn, for example, that your favorite "healthy" salad provides over 1,000 calories. Many restaurants these days have their nutrition information available to the public; this makes food logging even easier.

In addition to keeping a consistent food diary, consulting with a nutrition professional may be one additional factor that can help tip the scales in your favor, especially when done in conjunction with consistent physical activity.

The kind of food diary you keep will vary according to your personal preference. For example, you can record it on a handheld device, use an online food log (many free ones are available on the Web), or stick to traditional paper and pencil by using a notebook.

One of the most important points to remember about keeping an accurate and consistent food diary is to jot down what and how much you're eating immediately after eating it; don't kid yourself and say you'll remember everything later.

Whichever type of food diary you choose, it might just be worth a try!