People who stop taking weight loss medication return to their original weight in less than two years on average, according to an international review of weight loss drug trials.

The team looked at the results of 37 studies including over 9,000 participants who took weight loss medications – including but not limited to GLP-1 receptor agonists – for at least two months. The authors say it’s common for people to stop taking weight loss medications within the first year, and these findings show the need for caution when it comes to short-term use of weight loss drugs.

The All Ireland Science Media Centre asked experts to comment.

Dr Cathy Breen, Clinical Specialist Dietitian in Obesity with the Association for the Study of Obesity Ireland, RCSI, comments:

“The new obesity medications improve health and, on average, result in more weight loss than changes to health behaviours like food or activity alone. This is because they treat the hormonal aspects of the disease of obesity. Obesity is a chronic relapsing disease and so these treatments are designed to be used long-term, not in the short term to just target weight loss. The high discontinuation rates seen with these medications have many causes including the stigma associated with having obesity, costs and inadequate support to manage side effects. Health behaviours such as healthy nutrition, activity, sleep and stress management are foundations of obesity care, but it is outdated to suggest that medications are just an add-on – similar to all other chronic conditions, medications treat the physiology of the disease.”

Declarations of interest: “I have received honoraria for educational events or conference attendance from Astra Zeneca, Behaviour Change Training Ltd, Diabetes Ireland, European Association for the Study of Obesity, Eli Lily, International Medical Press, Medscape, MSD, Novo Nordisk and Sanofi Aventis”

Professor Raymond O’Connor, Adjunct Clinical Professor of General Practice, University of Limerick School of Medicine, comments: 

“The main findings that “average regain is 0.4kg/month and all weight lost likely to be regained in under 2 years and also that weight regain faster after stopping weight loss drugs than after dietary weight loss programmes” is not surprising.

“My own review on the topic is about to be published in the “Drugs and Therapeutics Bulletin”. In my review I found that discontinuation rates of GLP-1 RA drugs can be up to 60% after 1 year i.e. almost 2/3 of those starting the drug have stopped it within one year. Another study (the STEP-1 trial) showed that one year after withdrawal of once-weekly subcutaneous semaglutide 2.4 mg and lifestyle intervention, participants had regained two-thirds of their prior weight loss, with similar changes in cardiometabolic variables. Similar findings have been also found in several other studies. Tailored resistance exercise training and individualised dietary advice may be one way of retaining lean mass (muscle and bone) while achieving fat loss. However, in practice this rarely happens outside of specialised centres which have extremely long waiting lists.”

Declarations of interest: No conflicts of interest