A recent article in the New York Times showed that people who succeeded in losing large amounts of weight – say from 430 pounds to 190 – were rarely able to stay at their new weights. Most of the dieters in the New York Times article had lost large amounts of weight rapidly, as contestants in The Biggest Loser television program. When they began dieting they had normal metabolisms for their body size. When they had lost weight, their metabolisms had slowed radically and their bodies were not burning enough calories to maintain their thinner sizes. As the years went by their metabolisms did not recover, so they kept gaining back weight. It seemed that their bodies were working to pull the dieters back to their original weights. Investigators also found that the dieters had very low levels of leptin, a hormone made by fat cells that inhibits hunger. They were unable to detect satiety (feeling full).
This is discouraging news to people who want to lose weight for health reasons, such as having diabetes or certain kinds of heart disease. Research is ongoing on ways to improve this situation.
Are there other models of weight loss that would be more effective in the long term? We will look at the National Weight Control Registry for ideas. This organization was started by researchers from Brown Medical School and the University of Colorado, to look at people who have lost weight (at least 30 pounds) and kept it off for a year or more. People enroll voluntarily; 80% are women, and 20% men. On the average, weight loss has been 66 pounds, kept off for 5.5 years. Most people report maintaining a low calorie, low fat diet (25% fat) and doing high levels of physical activity. 78% eat breakfast daily; 75% weigh themselves at least once a week; 62% watch less than 10 hours of TV per week; 90% exercise, on average, about 1 hour per day. Changing beverage consumption to low/no calorie sweetened drinks is felt to be very important for weight loss and maintenance by the participants. People in the registry varied in the amount of exercise they did, and in their dietary plans. There was no ‘one size fits all’ formula being followed.
Dr. Barbara Rolls at Penn State University has written several popular books on making weight loss easier. Her latest is The Ultimate Volumetrics Diet. She has looked at ways to change the amount of water in foods, thereby adding weight and volume but no calories. This is done by adding vegetables to each recipe, and making sure the food is tasty. The result, found in careful studies, was that people reduced their calorie intake by about 25%. In a trial of 700 people, she found that when people ate a diet that was less calorie dense (more vegetables included) they were eating significantly more food – about a pound more food a day – yet they were eating fewer calories and easily losing more weight. She has many good ideas, backed by research, that keep people healthy while losing weight slowly. Read this book if you are frustrated about your weight. Aim to lose weight slowly, so that your metabolism can adjust more easily, And, whenever possible, keep moving!
Sadja Greenwood, MD,MPH back issues on this blog, including a column on Dr. Rolls & volumetrics,