October 28, 2011 by staff
Hunger Hormones, Any dieter knows that it is difficult to maintain the weight you’ve lost. Now a study finds that even a year after dieters shed a lot of weight quickly, your hormones are still insisting, “Come! Eat! Come!”
The results suggest that the diet they have regained weight is not just falling back into old habits, but are fighting a persistent biological urge.
“People who regain weight should not be harsh on themselves, as eating is our most basic instinct,” said Joseph Proietto, University of Melbourne in Australia, one of the authors of the study in an email. The research appears in Thursday’s New England Journal of Medicine.
The weight gain is a common problem for dieters. To study what drives it, Proietto and colleagues 50 patients with overweight or obesity in a diet program of 10 weeks in Australia. They wanted to see what would happen in people who lost at least 10 percent of their body weight. Ultimately, only 34 people lost a lot and stuck with the study long enough foranlysis.
The program was intense. On average, participants lost nearly 30 pounds over 10 weeks, faster than the standard advice to lose 1 or 2 pounds per week. They took in 500 to 550 calories a day with a meal replacement called Optifast more vegetables for eight weeks. After two weeks reintroduced gradually to common foods.
Despite the written guidance and advice on how to maintain their new weights, which gained an average of 12 pounds again during the next year. So weights were still lower than when they started.
Scientists tested the blood of nine levels of the hormones that influence appetite. The most important conclusion was comparing the hormone levels before weight loss program a year after it was over. Six hormones were out of control in the sense that increase hunger.
The diet also were rated as feeling hungry after meals in the one year mark, compared to what was reported before the diet program was started.
Experts not involved in the study said that the persistent effect on hormone levels is not surprising, and probably had nothing to do with the speed of weight loss.
People who lose less than 10 percent of body weight would probably show the same thing, although to a lesser degree, said Dr. George Bray of the Pennington Biomedical Research Center in Baton Rouge, Louisiana
A key message of the study is that “it is better not to gain weight than to try to lose,” said Bray.
Why would rebel a dieter’s body from losing weight? It is an evolutionary vestige of earlier times when the weight loss could jeopardize the survival and reproduction, says Dr. Rudolph Leibel, an obesity expert at Columbia University in New York. So “it is not surprising at all,” our bodies to fight for at least a year, he said. “This is probably a more or less permanent.”
People who lose weight more important not only appetite but also burn fewer calories than normal, creating a “perfect storm for the recovery of weight,” said Leibel.
He said that to prevent weight regain seems to be a fundamentally different weight loss first, and that researchers should pay more attention to it.
The study was supported by the Australian government, professional medical groups and a private foundation. Proietto served on a medical advisory board of Nestle, maker of Optifast, until last year.
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