Meta-analysis and construction of simple-to-use nomograms for approximating testosterone levels gained from weight loss in obese men.
Plain-language summary
This meta-analysis set out to measure how much testosterone men with obesity get back when they lose weight, comparing low-calorie diets with bariatric surgery. It pooled 44 studies covering 1,774 men, tracking total and free testosterone over a median follow-up of 26 weeks, and built nomograms (simple charts that read off an expected result from a man's starting weight and age) to predict the rise. Both routes raised testosterone and surgery raised it more. Younger men saw a bigger rise in free testosterone, while older men got more of their rise in total testosterone for the same weight lost. A second meta-analysis in this library asks the same question of the same literature, so the two overlap rather than confirming each other independently.
Key findings
- Weight loss raised total testosterone by 4.8 nmol/L on average, with bariatric surgery (7.2 nmol/L) doing more than low-calorie diets (2.5 nmol/L).
- Free testosterone rose by 42.2 pmol/L overall, with bariatric surgery (58.0 pmol/L) again ahead of diet (19.9 pmol/L).
- Men who started heavier, or with lower testosterone, recovered more of it.
- Younger men (40 and under) recovered more free testosterone, while older men recovered more total testosterone from the same weight loss.
How to analyze the study yourself
- Study type
- Meta-analyses pool results from many studies to spot patterns, but the quality depends on the original studies and how they are combined.
- Population
- Men with obesity, across a wide range of body mass index and starting testosterone. The pooled studies had baseline mean ages ranging from 21 to 68.
- Funding
- Not reported
- Takeaway
- This meta-analysis found that losing weight raises testosterone in men with obesity, with bariatric surgery producing the larger rise, and that younger men recovered more free testosterone than older men for the same weight lost. If you are carrying excess weight and your testosterone is low, weight loss is worth prioritizing, and if you are considering surgery it is worth raising with your doctor.