Men With Obesity Can Double Their Sperm Count

Men around the world are suffering from deteriorating sperm quality, often referred to as a real fertility crisis. But there is good news: In a clinical study, researchers from the University of Copenhagen and Hvidovre Hospital showed that the semen quality of men with obesity improves when they lose weight – and maintain the weight loss.

These findings could play a significant role in fertility, as a link between a higher sperm count and the faster onset of pregnancy has previously been demonstrated. The study was published in the recognised journal Human Reproduction, which enjoys one of the highest rankings in the field of fertility. A total of 56 overweight men aged between 18 and 65 with a body mass index between 32 and 43 took part.

Weight Loss Improves Sperm Count by 40 Per Cent

It has long been known that obesity is associated with reduced sperm quality. Previous studies have also suggested a link between weight loss and improved semen quality, but these studies had so few participants or so little weight loss that it was difficult to draw conclusions. This is the first long-term randomised trial, which showed that semen quality improves with sustained weight loss in men with obesity.

The men lost an average of 16.5 kg, which increased sperm concentration by 50 per cent and sperm count by 40 per cent eight weeks after weight loss. During the 52 weeks that the study lasted after the weight loss, the men maintained the improved sperm quality. But only those who maintained the weight loss: After one year, these men had twice as many sperm cells as before their weight loss. The men who regained weight lost the improvements in sperm quality.

Part of a Larger Study

The study is a sub-study of a larger publication on weight loss, which was published in the New England Journal of Medicine in May 2021. A total of 215 Danes with obesity took part in the larger study. Among these participants, 56 of the men also provided semen samples to investigate whether semen quality and weight loss could be related. In the study, all participants initially followed a low-calorie diet for eight weeks, which led to weight loss. The participants were then randomised into four groups.

Two of the groups received placebo medication, while the other two groups received anti-obesity medication. Of the two placebo groups, one group was required to complete an exercise programme that involved at least 150 minutes of moderate exercise or 75 minutes of rigorous exercise – or a combination thereof – each week.

The other group did not change their usual level of physical activity. The two groups receiving anti-obesity medication were divided into a group with and a group without an exercise programme in the same way, and after one year both the group that only exercised and did not receive medication and the group that only received anti-obesity medication and did not exercise maintained their weight loss of 13 kg. The group that received both anti-obesity medication and exercised also lost weight and improved their health. The placebo group – those who thought they were receiving medication but did not exercise – had regained half the weight loss, with many of the risk factors for developing type 2 diabetes and cardiovascular disease worsening.