Lower risk of death
- Published in
- BMJ 2017
- People studied
- 30,206
In 34 randomised trials in adults with obesity, weight-loss diet programmes went with about 6 fewer deaths per 1,000 people than comparison groups.
- Checked against
- PubMed 29138133
- Published in
- BMJ 2017
- Last checked
- 30 October 2026
Key takeaway
This review pooled 54 randomised trials with 30,206 adults with obesity, testing weight-loss diets, with or without exercise, for at least a year. In the 34 trials that reported deaths, the diet programmes went with an 18% lower risk of death from any cause, about 6 fewer deaths per 1,000 people. The evidence for this was rated high quality.
At a glance
- Type of study
- review pooling randomised trials (meta-analysis)
- People studied
- 30,206
- How long
- 1 year or more
- Compared with
- comparison groups in the trials
- Main result
- About 6 fewer deaths per 1,000 people with weight-loss diet programmes.
- Strength of evidence
- Randomised trials
What this study does not show
Deaths were rare (685 in 34 trials), and the effects on heart disease and cancer were not statistically clear. Almost all trials tested low-fat diets.
Results from studies in groups of people, mostly in diet and movement programmes. They cannot be promised to any one person. This information is educational and does not replace a consultation with a doctor.
More on whole body
- Lower risk of deathRandomised trials · Ma et al., BMJ 2017
- Linked with lower risk of some cancersLong-term or observational studies · Luo et al., JNCI Cancer Spectr 2019
- 13 cancer types linked with excess fatLong-term or observational studies · Lauby-Secretan et al., NEJM 2016
- Fewer deaths over 30 yearsRandomised trials · Gong et al., Lancet Diabetes Endocrinol 2019
- Lower risk of serious kidney diseaseRandomised trials · Look AHEAD Research Group, Lancet Diabetes Endocrinol 2014
- Stronger in later lifeRandomised trials · Villareal et al., NEJM 2011
The next step is a conversation, not a decision
A licensed doctor decides whether any treatment is right for you. The answer can also be no treatment.
1You fill in a short form
2We call you within 24 hours
3A paid 20-minute video consultation with a doctor
4The doctor goes through your options and decides what is right for you