New Insight into Losing Weight

What if a simple blood test could help you determine the best strategy for weight loss, before you even started? Additional analysis of a study conducted by researchers at the Jean Mayer USDA Human Nutrition Research Center on Aging (HNRCA) at Tufts suggests that a person’s fasting glucose levels, also called blood sugar levels, may be useful in figuring out the best type of diet for weight loss. The study focused on a weight-loss program based on the “iDiet,” which emphasizes a high-fiber, low-glycemic diet and includes behavioral support.

Tufts researchers, in collaboration with scientists from Gelesis, a biotechnology company, found that at the end of the six-month program, overweight and obese people with high fasting blood sugar levels lost more weight (an average of 9.4 percent of body weight) than those with low fasting blood sugar levels (4.1 percent body weight).

Senior author Sai Krupa Das, a scientist in the Energy Metabolism Laboratory at the HNRCA, explained that  high fasting blood sugar levels are a sign of poor glucose control, making people susceptible to blood glucose spikes when they eat, leading to hunger and overeating. A low-glycemic diet is designed to minimize those spikes. “Fasting blood sugar is easily measured, and our findings suggest that it could serve as a useful measure in advising some patients on the type of diet that is most beneficial for their weight loss,” Das said.

Most guidelines for weight control recommend that people with obesity lose 5-10 percent of their body weight to improve health. After six months, a greater proportion of subjects with high fasting blood sugar lost this recommended amount of weight, compared to those with low fasting blood sugar.

Almost 80 percent of subjects with high fasting blood sugar levels lost 5 percent of their body weight, compared to only 50 percent of subjects with low fasting blood sugar levels. In addition, 36 percent in the high group, vs. 8 percent in the low group, lost 10 percent of their body weight.

“The difference in response among those with high fasting blood sugar and lower fasting blood sugar is important. It might be time to consider glycemic status when advising patients on the best strategy for weight loss,” said study author Susan B. Roberts, senior scientist and director of the Energy Metabolism Laboratory at the HNRCA.

The analysis was published as a poster (with first author Lorien Urban, F09) at the American Diabetes Association’s 77th Scientific Sessions, so the data and conclusions should be considered preliminary until they have been published in a peer-reviewed journal.