Natural killer cells are an essential part of the immune system, killing viruses and leukemia cells, said Ulrich, who is also a research assistant professor in epidemiology at the University of Washington School of Public Health and Community Medicine. [...]It would be funny, if it weren't so sad, to see how the pro-dieting forces are attempting to spin the study results. Their conclusion is that the study proves, not that dieting is harmful, but that the women didn't take it far enough. People are urged to make dieting their permanent status; for example, one of the study authors recommends that people consume "few or no" refined carbohydrates and saturated fats for the rest of their lives. It's hard to imagine that such extreme and restrictive advice will lead to anything but the yo-yo effect of repeated weight loss followed by weight gain.
Those who reported losing weight more than five times had about a third lower natural killer cell function, the study found. Conversely, women who maintained the same weight for at least five years had 40 percent greater natural killer cell activity as compared to those who maintained their weight for fewer than two years.
All of the women in the study were described as sedentary. Ironically, if they had forgotten about dieting and moderately increased their physical activity level instead, they would have been far better off. The health benefits of exercise - improved immune function, lower risk of diabetes and high blood pressure, improved bone density, higher "good" cholesterol, improved mood - accrue at any weight. And even modest amounts of exercise (ten minutes, three times a day) result in significantly improved health.
Yet the independent benefits of exercise are being overshadowed by our current national obsession about weight loss. In the mid-1990s, the Surgeon General recommended that Americans get 30 minutes of moderate exercise a day. That recommendation was based on the amount of exercise necessary to lower the risk of chronic disease. But it's not generally enough to make people lose weight, so the recommendation was recently increased to an hour. Now, apparently, they're considering upping it again - this time to 60-90 minutes every day. In the endless quest to make every American svelte, they're setting exercise goals so unrealistic that most people will take one look and give up.