People who have obesity and regain weight lost through diet and exercise programmes still see long-term improvements in risk factors for heart disease and type 2 diabetes. This suggests there are health benefits to losing weight even if you gain it back.
Weight loss reduces the risk of chronic diseases related to obesity. However, previous research has shown that about half of people with obesity who participate in weight loss programmes regain the lost weight within five years.
To understand the long-term health effects of this, Jamie Hartmann-Boyce at the University of Oxford and her colleagues collected data on more than 60,000 adults from 124 randomised controlled trials of behavioural weight management programmes. These programmes encourage changes to diet or exercise habits to affect weight loss.
All the trials included data on one or more cardiometabolic measures – such as blood pressure, incidence of heart disease or cholesterol levels – at least 11 months after the programme’s end. Across trials, people who participated in behavioural weight management programmes lost, on average, 2.8 more kilograms of weight than people in control groups. They also regained 0.12 to 0.32 more kilograms each year after the programme ended.
People who participated in behavioural weight management programmes also saw small yet significant long-term reductions in cholesterol, blood sugar levels and blood pressure. Five years after ending a programme, participants’ cholesterol ratio was an average of 1.5 points lower than before the programme. They also saw a statistically significant reduction in systolic blood pressure and blood sugar levels. There was evidence, however, that the more weight that is gained back over time, the smaller and shorter-lasting these improvements are.
“When we actually think about the impact of this on a population level, it does suggest that fewer people might end up in the hospital with various [cardiometabolic] diseases,” says Hartmann-Boyce. However, the team found no statistically significant difference in incidences of cardiovascular disease or type 2 diabetes between those who participated in weight loss programmes and those who didn’t five years on. This may be because fewer studies collected data on these outcomes, says Hartmann-Boyce.
Still, the fact that there was a modest change in risk factors is meaningful, says Lauren Block at Northwell Health in New York. “A little bit can make a big difference” in terms of whether a person may need to take one or more medications, she says.
More research is needed to understand why weight regain doesn’t completely reverse the health benefits of weight loss. It could be that improvements in diet and exercise benefit health independent of weight loss, says Block. It may also be that weight loss delays the onset of health issues, says Hartmann-Boyce.
“If you are regaining weight, first of all, you’re not alone. But it also doesn’t mean that it wasn’t worth it. It doesn’t mean that there weren’t benefits,”she says.