What is the best way for long-term weight loss: exercise, diet, or pills? This new study has the answers.

Leaner individuals, who attempt weight loss exercise, dieting, or commercial programmes and pills, ended up gaining weight in the long run, with their 24-year risk of Type-2 diabetes also going up. In contrast, intentional weight loss in obese persons was found to be overall beneficial, according to a recent study the Harvard TH Chan School of Public Health.
Obesity is one of the biggest risk factors for developing Type-2 diabetes.
The researchers found exercise to be the most effective weight-loss strategy during a four-year follow-up – with the average weight being 4.2 per cent less in obese individuals, 2.5 per cent in overweight individuals and 0.4 per cent in lean individuals as compared to their counterparts who did not attempt weight loss. Among those who tried commercial programmes or diet pills, the obese weighed 0.3 per cent less, the overweight individuals weighed two per cent more, and the leaner individuals 3.7 per cent more than their counterparts.
What was the impact of weight loss on diabetes?
The researchers looked at the risk of Type-2 diabetes 24 years later and found that it went down in obese individuals irrespective of the weight-loss method attempted. The risk of diabetes went down 21 per cent in obese individuals who exercised and 13 per cent in those who took diet pills.
As for overweight people, the risk of diabetes went down nine per cent with exercise but shot up 42 per cent in those who took the pills.
In lean individuals, all weight loss strategies led to an increase in the risk of Type-2 diabetes. The risk increased nine per cent in those who lost weight through exercise and 54 per cent for those who took pills, according to the study.
“We were a bit surprised when we first saw the positive associations of weight loss attempts with faster weight gain and higher Type 2 diabetes risk among lean individuals. However, we now know that such observations are supported biology that unfortunately entails adverse health outcomes when lean individuals try to lose weight intentionally. Good news is that individuals with obesity will clearly benefit from losing a few pounds and the health benefits last even when the weight loss is temporary,” said Qi Sun from the department of nutrition at Harvard TH Chan School of Public Health in a release.
What does this study mean for India?
With around 77 million people in India living with diabetes – with the numbers projected to grow several fold in the coming years – should leaner individuals stop exercising? “No,” says Dr Ambrish Mithal, Chairman and Head of Diabetes and Endocrinology at Max Healthcare.
“Everyone, including those with lower BMI, should continue to do their regular exercise to maintain a healthy weight – we tend to put on weight as we age – and be physically fit. What they are not supposed to do is try and lose more weight,” he said.
“With over 80 per cent of Type-2 diabetes in people who are overweight and obese, when we talk of diabetes remission now, weight loss is a very important strategy. But we have always maintained that it cannot be the only strategy for everyone. When it comes to diabetes in leaner people, it may be because of less production of insulin rather than the cells being resant to it, and then weight loss will not be of help,” said Dr Mithal.
He said that sometimes hyper-aware persons, “someone who is lean and has been maintaining their HbA1c for years but now wants to get off all medications,” attempt to lose weight. “Reversal is not possible for everybody,” he said.
But who should be considered overweight in India? Dr Mithal as well as Dr Anoop Misra, Chairman of Fortis CDOC Center for Diabetes agree that a BMI cut-off of 25 for being overweight does not work in India.
“Even leaner Indians have a lot of fat around their belly, so the international cut-off for BMI 25 does not work here. I say, people should try to bring their BMI to around 21.5 in order to lose the fat stored in the liver,” said Dr Misra.