Can losing weight improve male fertility?
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Key takeaways
- Obesity affects around one in four Australian men of reproductive age and can reduce fertility.
- A new Genea led review examined which weight loss approaches actually improve sperm quality.
- Diet and exercise led to measurable sperm quality gains, even with modest weight loss.
- Bariatric surgery showed limited reproductive benefit, despite greater overall weight loss.
- Meaningful sperm quality improvements can happen within months through achievable lifestyle changes.
Why obesity and male fertility matter
Obesity affects around one in four Australian men of reproductive age, and it is a well recognised, modifiable cause of male factor infertility. Despite this, preconception guidelines have historically offered limited guidance on exactly which weight loss approach is most likely to help, or how much weight loss is actually needed to see a reproductive benefit.
Men considering weight loss ahead of trying to conceive generally have a few options, starting with lifestyle changes such as improved diet and increased physical activity, through to weight loss medications, and in more severe cases of obesity, bariatric surgery. Each approach differs in how much weight it typically helps someone lose, and until now, it has not been well understood whether the amount of weight lost is what actually matters most for fertility, or whether some approaches are simply better than others for reproductive health specifically.
The question this review set out to answer
This systematic review and meta-analysis, published in Human Reproduction Update, set out to synthesise the available evidence on the reproductive effects of obesity interventions in men. Where possible, the review also examined whether these effects depended on how much weight was actually lost.
Systematic reviews and meta-analyses that combine multiple studies are considered the highest level of scientific evidence available, since they pool findings across many individual studies rather than relying on any single trial. This review was led by Genea's Director of Research and Diagnostic Laboratories, Dr Nicole McPherson, alongside colleagues Andrew Peel, Hannah Lyons, Cathryn A Tully, Andrew D Vincent, David Jesudason and Gary Wittert.
How different weight loss approaches compare
- Diet and exercise Lifestyle changes involving improved diet and increased physical activity were linked to measurable improvements in sperm quality, and importantly, these benefits appeared even with relatively modest amounts of weight loss. This suggests lifestyle change offers real reproductive benefit, not just overall health improvement.
- Weight loss medications The review examined evidence on weight loss medications as part of its broader comparison of obesity interventions, considering how these approaches affect reproductive outcomes alongside lifestyle and surgical options.
- Bariatric surgery Despite typically producing greater overall weight loss than lifestyle changes, bariatric surgery showed limited reproductive benefit in this review. This was a notable finding, since it suggests the amount of weight lost is not the only factor that determines reproductive benefit.
What this means for men planning a family
This research offers practical, encouraging guidance for men who are overweight or living with obesity and planning to conceive. Rather than needing to pursue the most intensive weight loss option available, this review suggests that achievable lifestyle changes, improved diet and increased physical activity, can meaningfully improve sperm quality, often within a matter of months.
This does not mean weight loss medications or bariatric surgery have no place in a man's broader health journey, both can offer significant benefits for overall health and may be appropriate depending on individual circumstances. But for reproductive outcomes specifically, this review suggests that how weight is lost, and the broader lifestyle changes involved, may matter as much as how much weight comes off.
At Genea, research like this reflects our ongoing commitment to understanding fertility as a shared journey between partners, and to providing practical, evidence based guidance that helps people take meaningful steps toward starting a family.
What this means for you
If you or your partner are planning to conceive and obesity is a factor, this research offers a genuinely hopeful message, meaningful improvements in sperm quality are achievable, and they do not necessarily require dramatic intervention. Sensible, sustained lifestyle changes can make a real difference within a realistic timeframe.
Fertility is rarely about one partner alone, and taking steps to support male reproductive health is just as valuable as any other part of preparing for pregnancy. If you would like tailored guidance on lifestyle changes that may support your fertility, our team is here to help you build a plan that fits your circumstances.
FAQs
About the authors
Dr. Nicole McPherson
Director of Research and Diagnostic Laboratories
Dr Nicole McPherson is Genea Director of Research, Senior Lecturer and Hospital Research Fellow who leads the Sperm and Embryo Biology Group at Adelaide Uni.
View profileReferences
- Peel, A., Lyons, H., Tully, C. A., Vincent, A. D., Jesudason, D., Wittert, G., & McPherson, N. O. (2026). The effect of obesity interventions on male fertility: A systematic review and meta-analysis. Human Reproduction Update, 32(2), 154-180. https://doi.org/10.1093/humupd/dmaf025
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