Rapid weight loss carries risks, side effects.
One such risk is the formation of gallstones, Dr. Lawrence J. Cheskin said at the meeting. Prevention strategies include limiting the rate of weight loss to an average of 3.3 pounds per week, said Dr. Cheskin, director of the Johns Hopkins Weight Management Center in Baltimore.
Adding 10 g of fat to a low-calorie diet has also been shown to prevent gallstone formation, probably because of enhanced gallbladder emptying. "Once the gallstones get big enough to get impacted, that's not going to work," he said.
Another strategy is to add polyunsaturated fatty acids to the diet, although this approach has not been studied beyond 6 weeks of follow-up.
Ursodeoxycholic acid has been shown to be effective in preventing gallstones, he said, whereas the results of placebo-controlled trials of prostaglandin inhibition with NSAIDs are mixed. There is also emerging evidence that ECCG (ezetimibe and epigallocatechin gallate) may play a role in the prevention of gallstones.
He went on to discuss the following medical problems that are related to rapid weight loss:
* Kidney stones. These tend to occur at greater frequency with low-carbohydrate, high-protein diets. "It likely results from elevated uric acid in blood and urine, increased urinary calcium, and acid load/acidification of the urine," Dr. Cheskin explained.
Prevention strategies include daily ingestion of potassium citrate, "because it alkalinizes the urine and solubilizes urinary calcium," he said. "There's also some evidence that adding magnesium to potassium citrate may be even more effective."
* Gout. This can occur from temporary elevations in uric acid. "People on very-low-energy diets have a reported gout incidence rate of 1%," he said. "Generally, though, the risk of gout ultimately decreases with weight loss and its accompanying lowering of serum uric acid."
Prevention strategies include exercise, limitation of red meat and sugary beverage intake, and supplementation with coffee and vitamin C. "Coffee and vitamin C seem to lower uric acid levels in general," he said.
* Cardiac complications. Concerns about arrhythmias and deaths arose many years ago, when diets were sometimes very deficient in protein and micronutrients, "but very rarely today," Dr. Cheskin said.
* Electrolyte disorders. Dr. Cheskin advises being vigilant in monitoring levels of serum potassium and magnesium, especially in patients who are on diuretics.
* Bone density loss. This remains an area of controversy, Dr. Cheskin said, as it is unclear if the bone loss exceeds the loss that is expected from the weight loss itself.
* Eating disorders. "Though a cause and effect [relationship] has not been well established, clearly, repeated dieting can be associated with eating disorders," he said. "We should bear this in mind and not shy away from helping people with eating disorders related to dieting."
Dr. Cheskin said he had no relevant financial conflicts to disclose.
BY DOUG BRUNK
EXPERT ANALYSIS FROM THE ANNUAL MEETING OF THE OBESITY SOCIETY
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|Publication:||OB GYN News|
|Date:||Jan 1, 2011|
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