Male fertility is heavily influenced by lifestyle factors, particularly weight and metabolic health, according to leading reproductive medicine experts presenting at the European Society of Human Reproduction and Embryology's 42nd Annual Meeting in London. Obesity and related metabolic conditions can substantially harm sperm production and quality through multiple biological mechanisms, but the good news is that targeted interventions like diet and exercise show strong promise for improvement.

How Does Obesity Damage Male Fertility?

Obesity affects male fertility through several interconnected pathways. When men carry excess weight, it disrupts the hormonal axis that controls testosterone production, leading to lower testosterone levels. Beyond hormones, visceral fat (the deep belly fat surrounding organs) physically overheats the testicles, which directly interferes with sperm production. Additionally, obesity creates a chronic inflammatory state in the body that damages sperm DNA, reducing both sperm quality and fertility potential.

The impact is significant enough that reproductive medicine specialists now routinely discuss weight management with male patients seeking to optimize their fertility. Understanding these mechanisms helps explain why so many men ask their doctors, "What can I do to help improve my fertility?" The answer increasingly points to modifiable lifestyle factors.

What Lifestyle Changes Actually Work for Male Fertility?

Research presented at the meeting identified specific interventions that show measurable benefits for male fertility. The evidence is particularly strong for two approaches:

• Diet and Exercise: Consistent evidence shows that improving diet quality and increasing physical activity produce meaningful gains in sperm production and sperm concentration, making this the most reliable intervention for men with obesity-related fertility problems.
• Weight Loss Through Lifestyle: The mechanism matters; weight loss achieved through diet and exercise appears more effective for fertility than weight loss from other methods, suggesting that the specific pathway to weight reduction influences reproductive health outcomes.
• GLP-1 Agonist Medications: A randomized controlled trial examining GLP-1 receptor agonists (medications like semaglutide used for weight management) found that as long as weight is maintained, these drugs appear to support gains in sperm production and concentration, offering a pharmaceutical option for men who struggle with lifestyle changes alone.

Notably, bariatric surgery (weight loss surgery) did not show fertility benefits in the literature reviewed, despite achieving significant weight loss. Researchers hypothesize this may be due to nutrient deprivation or other factors related to how the gut processes nutrients after surgery.

"Our patients want to be empowered. They ask us, like, what can I do to help optimize my fertility? And there actually is a lot that they can do. If we take a careful look at the literature, we find that obesity and the components of metabolic syndrome that go along with that on the male side can have a substantial negative effect," said Dr. Robert Brannigan, President of the American Society for Reproductive Medicine.

Dr. Robert Brannigan, President, American Society for Reproductive Medicine

What About Newer Weight Loss Medications?

The emerging question around GLP-1 agonist medications reflects broader interest in how newer weight loss tools affect fertility. These medications work by reducing appetite and improving blood sugar control, but their specific impact on reproductive health was largely unknown until recently. The one randomized controlled trial published so far suggests that the fertility benefits come from the weight loss itself, not from any special property of the medication.

However, researchers acknowledge they don't fully understand all the biological pathways involved. The benefits likely stem from improvements across multiple systems: reduced inflammation, lower scrotal temperature, restored testosterone levels, and decreased sperm DNA damage. More research is expected in the coming months, with additional randomized controlled trials potentially presenting findings at the American Society for Reproductive Medicine's annual meeting scheduled for October 2026.

For men considering their fertility options, the takeaway is clear: weight management through diet and exercise remains the gold standard, supported by strong evidence. For those who struggle with lifestyle changes alone, emerging pharmaceutical options may offer additional support, though they work best when combined with sustained weight loss.

Why Should Men Care About This Now?

Male factor infertility accounts for roughly half of all infertility cases, yet it receives less attention than female fertility in public health discussions. By understanding that male fertility is modifiable through lifestyle choices, men can take active steps to improve their reproductive health before pursuing expensive fertility treatments. This is particularly important given that fertility treatments like in vitro fertilization (IVF) are costly and not universally covered by insurance.

The research presented at the international meeting underscores a broader shift in reproductive medicine: moving away from viewing fertility as purely a matter of genetics or age, and toward recognizing the powerful role of modifiable health factors. For couples planning to conceive, this means both partners should consider their weight, diet, and exercise habits as part of their fertility strategy.