No calorie counting or additional exercise. He lost 22 lbs in 11 weeks. He continued his recording for 6 years and continued to maintain the weight he lost. He reported that the task of writing down the food he had eaten helped him change his behavior because it made him review what he has eaten during the day. Recording demonstrated and reinforced his belief he could lose weight and keep the weight off.
Weight loss depends upon creating and sustaining a cumulative calorie deficit over time.
It is very easy to lose control of calories by being unaware or forgetting what you ate. It is also very common to underestimate the calories you eat. Recording your daily calories objectifies your behavior in a way that allows you to view and manage your calories more effectively. In reality, the nominal weight loss is telling them they really are on diet much higher than 1200 calories. Their perception of a 1200 calorie diet and the results are incongruent and is typically due to not following the diet plan closely enough.