A large weight loss, even if regained, may help overweight people with type 2 diabetes improve their blood sugar control and cholesterol and lower high blood pressure long-term, a new study suggests.
Over four years, even those who regained all of a large weight loss had greater improvements in blood sugar than their counterparts who lost no weight or initially lost a smaller amount.
"Since many people lose weight and regain some (or all) of it, it is important to know whether this pattern leads to better or worse outcomes than never losing weight," said coauthor Rena Wing, a professor of psychiatry and human behavior at The Warren Alpert Medical School of Brown University.
Wing also directs the Weight Control and Diabetes Research Center at The Miriam Hospital in Providence Rhode Island.
"Our data shows no negative effects of losing weight and regaining on (cardiovascular disease) outcomes," Wing told Reuters Health by email.
The researchers used data for more than 1,400 overweight or obese adults with type 2 diabetes in a 10-year randomized trial of intensive diet and exercise changes compared to no lifestyle changes.
Participants aimed to lose at least 7 percent of their body weight and to do 175 minutes of moderate-intensity physical activity. For these results, the researchers focused on the first four years of the 10-year study.
They divided the participants into six categories based on their progress: no weight loss, moderate weight loss of 3 to 8 percent of body weight, large weight loss of 8 to 20 percent of body weight, moderate weight loss that was fully regained by year four, large weight loss that was fully regained by year four and large weight loss that was only partly regained. Most often, people lost a large amount of weight and partly regained it.
Larger weight loss improved blood sugar control, systolic blood pressure, cholesterol and triglyceride levels more than lesser weight loss at year one and year four, as reported in Diabetes Care.
Blood sugar control tended to improve in the first year and then worsen again. At year four, it was only still improved among people with large weight losses - and that was true regardless of whether the large weight loss had later been regained.
"Weight loss reduces adipose tissue and improves insulin sensitivity," Wing said. "These changes lead to reductions in inflammation and improvement in (cardiovascular disease) risk factors," she said.
"There are a number of studies showing that weight loss can have a sustained impact even if weight loss is regained," Wing noted, including reducing risk of diabetes for people who do not have it yet. Researchers call these "legacy effects" or "metabolic memory," she said.
But the last measurements for this study were made at year four, so it's not clear whether the apparent "positive effects" will still be there at year five or later, noted professor Abdul G. Dulloo of the University of Fribourg in Switzerland, who was not part of the new study.
"Furthermore, we seem to be dealing here with one cycle of weight loss/regain, and how multiple phases of weight loss/regain (i.e. multiple weight cycling) affects these risks for cardiovascular disease remains uncertain," Dulloo told Reuters Health by email.
In any case, "it is best to lose weight and maintain it," Wing said. "However, fear of regaining should not stop people with diabetes from trying to lose weight."