New Delhi: Weight-loss medications have transformed obesity treatment in recent years, helping many patients shed significant amounts of weight. But a new analysis suggests that the challenge often begins after the medication is stopped. Researchers from the University of Oxford have found that many people regain weight relatively quickly once they discontinue anti-obesity drugs. Their findings, published in The BMJ, indicate that weight tends to return faster after stopping medication than after completing behavioural weight-loss programmes focused on diet and lifestyle changes.
The research team analysed data from 37 clinical studies involving more than 9,300 adults who had taken medications for weight management. Participants had typically used the drugs for about 39 weeks before stopping treatment and were monitored for several months afterwards to track what happened next.
On average, people gained about 0.4 kilograms per month after discontinuing medication. If that trend continued, researchers estimated that many individuals would return to their original weight within roughly 18 months to two years.
The rate of regain appeared even higher among patients who had used newer drugs such as semaglutide and tirzepatide, medications that have gained global attention for their effectiveness in producing substantial weight loss. Among users of these drugs, weight increased by an average of around 0.8 kilograms per month once treatment stopped. Although long-term data beyond one year is still limited, projections suggest that many patients could return to their baseline weight in about a year and a half.
To better understand the findings, the researchers also compared the results with outcomes from behavioural weight-loss programmes, such as structured diet and exercise interventions. These programmes also see some degree of weight regain over time. However, the analysis showed that the pace of regain was slower compared with what was observed after stopping medication, by about 0.3 kilograms per month.
One possible explanation, researchers say, lies in the different ways these approaches produce weight loss. Lifestyle programmes require people to make conscious adjustments to their eating habits and activity levels, helping them develop skills that may support long-term weight maintenance. Medications, by contrast, act on appetite and metabolic pathways, meaning individuals may lose weight without necessarily changing the routines that influence body weight over time.
The study also tracked various health indicators associated with obesity. Measures like blood pressure, sugar, and cholesterol usually improve during the period when one is on medication. However, once off, these markers drift to their former levels rather swiftly. Therefore, experts warn that the findings must not be seen as criticism of weight loss drugs. Rather, one must reflect on better and safer ways of sustaining weight loss after going off the medication.
Researchers note that medication plays a crucial role in treatment, but it can be most effective with long-term lifestyle support or follow-up care. The authors of the study also noted that more research is required in the area to be fully sure of the outcome.