Fertility and a man’s weight

Being overweight, especially significantly so, can affect a man’s fertility. Being underweight can also reduce a man’s fertility. So if you’re planning to have a baby in the next year or few years, healthy eating and regular exercise can boost your fertility.

Being overweight can affect a man’s fertility.

Being overweight

Being overweight, especially significantly so, can affect a man’s fertility. So if you’re a guy, you’re overweight and planning to have a baby in the next year or few years, you might want to act now to lose weight. Start a healthy eating and exercise plan now to increase the odds of your partner (or surrogate) getting pregnant and having a healthy baby.

Being overweight or obese can also have a negative effect on a woman’s fertility, including the time it takes to get pregnant. It can also cause complications for pregnancy and birth.

How can I tell if I’m overweight or obese?

The usual way to find out if you are ‘overweight’ or ‘obese’ is by calculating your body mass index or BMI. This is a weight to height ratio where your weight in kilograms is divided by the square of your height in metres. A BMI calculator – and more information about BMI – are available at the Better Health Channel. A healthy BMI is considered to be between 18.5 and 24.9. A BMI between 25 and 29.9 is classified as ‘overweight’ and over 30 as ‘obese’.

How can I lose weight?

With a healthy eating plan and regular exercise, you’ll be on your way. View our healthy weight fact sheet for some tips on how to LiveLighter.

The Dieticians Association of Australia website has some excellent information about creating your own healthy diet plan. Visit the Australian Government’s Healthy Weight website for more information about a ‘balanced diet’ and guidelines for how much exercise you need to do to both lose weight and maintain a healthy weight.

The facts about men, weight and fertility

Overweight and obese men have worse sperm quality than men of healthy weight. Being overweight or obese can also cause hormonal changes that reduce fertility and make men less interested in sex. Men who are very overweight are also more likely to have problems getting an erection. Together, these factors reduce the chances of men who are overweight or obese fathering a child.

Being underweight

Being underweight can also reduce a man’s sperm quality and therefore his fertility. A BMI under 18.5 is classified as ‘underweight’.

Myth conception

The myth:

"A man’s weight doesn’t affect his fertility."

The truth:

Being overweight and obese reduces a man’s fertility.

Overweight and obese men have worse sperm quality than men of healthy weight. Male obesity can reduce fertility by lowering testosterone levels and increasing the risk of erectile dysfunction. Together, these factors reduce the chances of men who are overweight or obese fathering a child.

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