Health
Yo-yo dieting bad for immune system
NEWS IN BRIEF — Posted June 21, 2004
Repeatedly losing and gaining weight reduces the number of natural killer cells that defend the body against viruses and cancer, according to the June Journal of the American Dietetic Assn.
Researchers at the Fred Hutchinson Cancer Research Center in Seattle recruited more than 100 overweight, sedentary, postmenopausal women to answer a questionnaire about weight loss and gain. Levels of NK cells were also measured. Women who had maintained a stable weight had higher levels of these cells while those who had ever lost 10 pounds had lower levels. Repeated weight loss was associated with lower numbers of these cells.
Authors of the paper said that maintaining a healthy weight was still better than carrying a few extra pounds, but that yo-yo dieting was a definite danger.
"There are indisputable health benefits to reducing body weight among those who are overweight and obese," said Cornelia Ulrich, PhD, lead author and assistant member of the Center's Public Health Sciences Division. "Our concern is really the pattern of weight cycling or yo-yo dieting that many Americans go through."
Note: This item originally appeared at http://www.ama-assn.org/amednews/2004/06/21/hlbf0621.htm.
