Focusing on weight loss alone for obesity may do more harm than good, suggests study

Focusing solely on achieving weight loss for people with a high body mass index (BMI) may do more harm than good, argue experts in The BMJ today.

Dr Juan Franco and colleagues say, on average, people with high weight will not be able to sustain a clinically relevant weight loss with lifestyle interventions, while the potential harms of weight loss interventions, including the reinforcement of weight stigma, are still unclear.

They stress that a healthy lifestyle has important benefits, but that weight alone might not give an adequate picture of someone’s health, and say doctors should provide high quality, evidence based care reflecting individual preferences and needs, regardless of weight.

Lifestyle interventions that focus on restricting an individual’s energy intake and increasing their physical activity levels have for many decades been the mainstay recommendation to reduce weight in people with obesity, explain the authors.

However, rigorous evidence has indicated that these lifestyle interventions are largely ineffective in providing sustained long term weight loss and reducing cardiovascular events (eg, heart attacks and strokes) or death.

Even though a healthy lifestyle provides important benefits, acknowledging that weight alone might not give an adequate picture of someone’s health, and recognising the limitations of lifestyle interventions for weight loss, could pave the way for more effective and patient centred care, they say.

Focusing on weight loss might also contribute to societal weight bias - negative attitudes, assumptions, and judgments about people based on their weight - which may not only have adverse effects on mental health but may also be associated with disordered eating, the adoption of unhealthy habits, and weight gain, they add.

They point out that recent clinical guidelines reflect the growing recognition that weight is an inadequate measure of health, and alternative approaches, such as Health at Every Size (HAES), acknowledge that good health can be achieved regardless of weight loss and have shown promising results in improving eating behaviours.

While these approaches should be evaluated in large clinical trials, doctors can learn from them to provide better and more compassionate care for patients with larger bodies, they suggest.

“Doctors should be prepared to inform individuals seeking weight loss about the potential benefits and harms of interventions and minimise the risk of developing eating disorders and long term impacts on metabolism,” they write. “Such a patient centred approach is likely to provide better care by aligning with patient preferences and circumstances while also reducing weight bias.”

They conclude: “Doctors’ advice about healthy eating and physical activity is still relevant as it may result in better health. The main goal is to offer good care irrespective of weight, which means not caring less but rather discussing benefits, harms, and what is important to the patient.”

Reference:

Franco J V A, Grundtvig Gram E , Meyer L, Grandi D, Cruzat B, Christiansen L B et al. Beyond body mass index: rethinking doctors’ advice for weight loss BMJ 2025; 389 :e084654 doi:10.1136/bmj-2025-084654.