About Weight Loss and Weight Loss Maintenance

The topic for the day was America's obesity problem. Surprisingly, there was a fair amount of good news about weight loss generated by the recent obesity media briefing, held last month in New York City and sponsored by the American Medical Association. For example, simply increasing calcium intake (2,000 mg daily) will keep the pounds off some people. This was an accidental finding from a study designed for a purpose other than weight loss. It was confirmed by another study designed to see if this finding could be replicated.

Obesity researchers usually study treatment failures to determine what went wrong, but one doctor who spoke at the media briefing described a national registry of 3,000 people who successfully managed to not only lose weight but also keep it off. They are being studied to determine the secret to their success.

But first, the reporters had to hear the litany of bad news about obesity and its adverse consequences. Doctors who addressed the media briefing were especially worried about the large increase in the diagnosis of type 2 diabetes over the last decade. The rise parallels the increase in the number of Americans who are either overweight or obese. According to a recent study by the RAND Institute, being overweight, especially obese, has the most deleterious effect on health after smoking, drinking, or poverty. Other health complications associated with excess weight include gallbladder disease, cancer, pregnancy-related ailments, and joint problems.

The rise in childhood obesity has become an area of special concern. Non-insulin dependent (type 2) diabetes, which typically appears in middle age, was rare in children as recently as 20 years ago, said William H. Dietz, MD, director of the division of Nutrition and Physical Activity, U.S. Centers for Disease Control and Prevention in Atlanta. Now, type 2 diabetes is almost as frequent a diagnosis in children as type 1 diabetes, warned Dr. Dietz. He listed several reasons for the rise in childhood obesity, including massive changes in the food supply [more processed food, more junk food], the increased consumption of soda, increased reliance on cars (and lack of sidewalks in many areas), and changes in the amount of time children spend watching TV.

Breastfeeding, the longer the better, is a protection against childhood obesity, Dr. Dietz explained, as is reducing the amount of TV children watch. He described studies that have correlated the increase in weight gain with the quantity of TV watching. However, it is not known whether the weight gain is due to the time spent being sedentary or the type of foods advertised to children on TV. Significantly, about 75% of American children's food intake occurs while watching TV.

Attempts to lose weight often fail once the dieter gets to the weight maintenance phase, said James O. Hill, PhD, University of Colorado Health Sciences Center, who cited studies demonstrating that less than 5% are successful in keeping the weight off. But Dr. Hill has redefined success, which used to mean going down to and maintaining an ideal weight. Instead, he defined success as a 10% weight loss that is maintained for at least a year, which can provide significant health benefits. Dr. Hill has been studying people who are successful according to these criteria. Over 3,000 people volunteered to participate in the National Weight Control Registry. Having lost 66 pounds on average, these people are being studied to learn how they did it.

"Weight loss and weight maintenance are two different things," explained Dr. Hill, "There's too much focus on diet and not enough on physical activity." The weight loss method turned out to be unimportant to the success of the 3,000 people, who have been dubbed "successful losers" by the researchers. Half of them lost the weight on their own, and half chose a formal program like Jenny Craig or Weight Watchers.

While there were no similarities in how they lost weight, there were four characteristics common to successful weight maintenance: eating a low-fat, high-carbohydrate diet; eating breakfast almost every day; self-monitoring (e.g., weighing themselves frequently, keeping a food journal --as long as 20 years after weight loss); and engaging in physical activity for an hour each day. The physical activity, Dr. Hill observed, is twice the usual recommended amount of time spent exercising. The majority chose walking and did not necessarily do it all at once. Often they exercised in increments--walking for a half hour, taking the stairs instead of an elevator, etc. The successful losers ate five times a day; they ate out periodically but avoided fast food restaurants. Dr. Hill said, "90% had failed at previous weight loss attempts and noted that paying attention to their weight was the key to maintaining weight loss." Drugs were not important to success, said Dr. Hill in answer to a reporter's question. He guessed that the reason for this was the fact that the Registry was established in 1994 when fewer people were taking drugs for this purpose.

If overweight people lose even a small amount of weight, they will cut their risk of developing type 2 diabetes. This was shown in a study of 522 middle-aged Finnish people who were at high risk for developing type 2 diabetes because of impaired glucose tolerance (New England Journal of Medicine, 5/3/01). Losing less than ten pounds cut the risk dramatically. Significantly, a reduced risk was also shown in people who added more than four hours of exercise to their weekly routine, but did not lose weight.

Surgery should play a much larger role in the treatment of obesity, according to George A. Bray, MD, professor at Louisiana State University. "Obesity is a time bomb to be defused," he said, acknowledging the complications of surgery but dismissing them as less problematic than the consequences of being seriously obese.

Dr. Bray described an ongoing clinical trial called the Swedish Obese Subjects Study, which compares the results of three forms of surgery: gastric bypass, gastric banding, and vertical banded gastroplasty. All are variations on dividing off a small section of the stomach. While answers from this trial will not be available for a long time (participants have been followed for only two years), Dr. Bray said that initial results favor gastric bypass surgery. He described the surgery, "The stomach is divided into a small (ten teaspoon size) pouch and the larger lower stomach. The food that enters the upper stomach passes into the small intestine that is attached to the pouch. Juices from the lower stomach and upper intestine join the stomach contents further down the intestine."

Use of the laparoscope in obesity surgery has greatly reduced the mortality of this treatment choice, said Dr. Bray. Instead, of cutting open the abdomen, the surgery is performed through a telescopelike instrument.

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