Publish date: 28 April 2022

People with obesity whose weight and health improve following drug treatment are likely to need the treatment long term, according to a study at UCLH and UCL which highlights the chronic nature of obesity.

The STEP 1 trial followed people who took a ground-breaking new drug for obesity, semaglutide, alongside lifestyle intervention. Findings published in 2021 showed 75% of people who took the drug lost more than 10% of their body weight and more than one-third lost more than 20%, with the drug being hailed as a ‘game changer.’

One year after the withdrawal of treatment, however, participants regained two-thirds of their prior weight loss, according to the latest data from the study. Participants’ risk of cardiometabolic diseases such as diabetes also went back up again.

The findings suggest obesity is like other conditions which require ongoing treatment, such as high blood pressure, COPD and asthma.

Semaglutide works by hijacking the body’s own appetite regulating system in the brain leading to reduced hunger and calorie intake. In the study it was given by injection alongside lifestyle intervention, which included advice on diet and a recommendation of 150 minutes of physical activity per week.

In February 2022, the National Institute for Health and Care Excellence issued draft guidance recommending use of the drug for some patients.

Professor Rachel Batterham, who is Obesity Theme Director at the UCLH Biomedical Research Centre and who leads the UCLH Centre for Weight Management and the Centre for Obesity Research at UCL, is one of the principal researchers on the study.

She said: “If we treat a person with high blood pressure with an antihypertensive drug, their blood pressure returns to normal. This does not mean they do not have hypertension; they have treated hypertension. The same is true with obesity. Weight loss treatments cause weight loss but if we stop them, then the majority of people will regain most of the weight lost. This suggests the importance of ongoing treatment for patients to sustain weight and health improvements.”