What are the side effects of yo yo dieting?
Losing weight is good, but losing and regaining weight over and over can damage the immune system, according to a new study. Some research has already suggested that “yo-yo dieting” or “weight cycling” is harmful. But an author of the new study, Dr. Cornelia M. Ulrich of the Fred Hutchinson Cancer Research Center in Seattle, said the warnings against the practice had for the most part been based more on intuition than hard evidence. Dr. Ulrich and her colleagues questioned 114 overweight but healthy women older than 50 about their weight histories. Almost three-quarters of the women, the researchers found, had lost more than 10 pounds at least once by dieting in the previous 20 years. More than half had done that two or more times. The researchers also measured the levels of natural killer cells, immune system cells that aim at viruses and may have a role in fighting cancer, as well. The women who had yo-yo’d most often – five times or more – had the lowest levels of the killer cells;
