Weight and body mass have a large impact on fertility – while previous research has largely focused on the link between female weight and fertility, a recent study published in the journal Andrologia has found that male obesity is associated with lower sperm volumes, sperm count, concentration, motility, and more sperm defects.
A person is considered obese if their bodyweight is at least 20% higher than it should be – this coincides with having a body mass index (BMI) of 30 or above. 28.1% of adults in the UK are obese, with just 34% of men having a healthy BMI of 18.5-25.
Obesity is also associated with a variety of other health issues, such as high blood pressure, type 2 diabetes, heart disease, and stroke. If you are planning to conceive, it is essential that you consider your body weight and body fat, and maintaining a healthy weight and diet as part of the process.
Men who are overweight (not just obese) are 11% more likely to have a low sperm count and 39% more likely to have no sperm in their ejaculate than men who maintain a healthy weight. These figures rise to 42% and 81% in obese men.
It takes up to 3 months for the body to create new sperm, so efforts to improve health and weight should be made as soon as possible once you make the decision to start a family.
The west is facing an obesity crisis, and this new research may help to explain why sperm counts in these countries have fallen by 52%.
The team who carried out the study are now working on follow-up research to see whether losing weight helps to improve sperm quality. Findings so far suggest that sperm quality does improve as men lose weight.