Even a small amount of weight loss could lead to a big gain in health benefits for obese people.
Researchers at Washington University School of Medicine in St. Louis found significant health benefits when obese patients lost just five percent of their total body weight.
Obesity is measured using body mass index (BMI=kg/m^2), which defines overweight as a BMI between 25.0 and 29.9; and a BMI of 30 or higher as obese, according to the Harvard School of Public Health. Obesity has many health risks, including heart disease and diabetes, however, weight loss is difficult for many patients.
Current guidelines recommend obese patients lose five to 10 percent of their body weight. For someone who weighs 250 pounds, that's 12.5 to 25 pounds. This new study indicates the lower value is a perfectly good target.
"Our findings demonstrate that you get the biggest bang for your buck with five percent weight loss. The current guidelines for treating obesity recommend a five to 10 percent weight loss, but losing five percent of your body weight is much easier than losing 10 percent. So it may make sense for patients to aim at the easier target," Samuel Klein, MD, and principal investigator commented in a press release.
Klein is the director of Washington University's Center for Human Nutrition.
Dr. Klein and colleagues assigned 40 obese individuals to one of four groups. The first group simply maintained their body weight. The remaining groups lost five, 10 or 15 percent of their body weight by dieting.
Researchers assessed body, organ system and cellular responses before and after the weight loss. The results showed that patients who lost five percent of their body weight had improved insulin secretion. Insulin is the hormone that regulates blood sugar.
With a five percent weight loss, the patients' cells also became more sensitive to the effects of insulin. This is important because people who are obese develop insulin resistance, and may eventually develop type 2 diabetes.
A five percent weight loss also resulted in decreased body and liver fat.
Of the patients who lost 15 percent of their total body weight, insulin secretion and sensitivity in muscle tissue continued to improve. However, insulin sensitivity in the liver did not get any better, and patients who lost more weight did not lose more fat in the liver.
One finding surprised the researchers. Inflammation is common in people with obesity. However, inflammation did not improve with weight loss in this study.
"If you weigh 200 pounds, you will be doing yourself a favor if you can lose 10 pounds and keep it off,” Klein said in the press release. “You don't have to lose 50 pounds to get important health benefits."
The study was published in the February issue of Cell Metabolism.
Information on study funding and conflict of interest was not available.