The study tracked nearly 1,700 overweight or obese adults across the country who were at least 25 years old. Men and women were included, and 44% of the group was African American. All participants were encouraged to use such weight-loss maintenance strategies as calorie restriction, weekly group sessions and moderately intensive exercise as well as to keep a food journal. The senior investigator, Victor Stevens of Kaiser Permanente Center for Health Research in Portland, Ore., told me that "hands down, the most successful weight-loss method was keeping a record of what you eat." In the six-month study, participants who kept a food journal six or seven days a week lost an average of 18 lb. (8 kg), compared with an average of 9 lb. (4 kg) lost by non-diary keepers.
Why A Food Diary Will Double Your Weight Loss