Losing weight can help men DOUBLE their sperm count, study claims

Losing weight can help fat men DOUBLE their sperm count, study claims

  • Men who lost 2st 8lbs (16.5kg) in 8 weeks increased their sperm count by 41%
  • But if they kept the weight off for a year their sperm count doubled, experts said 
  • UK and US waistlines have grown while sperm counts have fallen since the 70s

Losing weight could help fat men double their sperm count, researchers say. 

Danish scientists say the discovery — based off just 56 men — was ‘surprising’.

All volunteers were shoved onto an eight-week diet, consisting of just 800 calories per day. 

The men, who had a BMI of at least 32 before the study began, lost 2st 8lbs (16.5kg) on average. 

Over the same time, their sperm count jumped by 41 per cent.

Men who kept the weight off for a year had twice as many swimmers, compared to before the study began.

However, participants whose belly fat rebounded ‘lost the improvements in semen quality’, experts at Copenhagen University found.

A study by Danish experts found that men who lost 2st 8lbs (16.5kg) and kept the weight off for a year doubled their sperm count (graphic)

Sperm counts: What’s normal and when to seek help 

A low sperm count, medically called called oligozoospermia, is when a man has fewer than 15 million sperm per millilitre of semen.

Having a low sperm count doesn’t mean being infertile, but it does mean could have trouble conceiving.   

Problems with sperm, including a low sperm count are a factor in around a third of couples who are struggling to get pregnant. 

Couples struggling to conceive after a year of trying should see their GP.

Both the man and woman should seek advice as fertility problems can affect both men and women. 

One of tests a GP can arrange to determine if a man has a problem is a semen analysis which can detect a low sperm count. 

Sperm counts generally decline in age, peaking when a man turns 17 and remaining high until their 40s.

A normal sperm count is considered to be any amount greater than 15million of sperm per millilitre of semen.

But levels among men have been plunging overall since the 1970s, studies in Europe, North America and Australia show.

Scientists believe bigger waistlines, poor diets and even exposure to pollution could be behind the worrying trend.

Men involved in the new study, published in the journal Human Reproduction, were aged between 18 and 65. 

They were given meals made by Cambridge Weight Plan, a company that makes low-calorie meal versions of pastas, traybakes and burgers. 

Lead researcher Professor Signe Torekov said: ‘It was surprising to us that such a big improvement can be shown in the semen quality in connection with a weight loss. 

‘And as 18 percent of Danes have obesity, this new knowledge may actually make a difference.’

However, the study is unlikely to apply to just Danish men, with rising obesity and lowering sperm quality being recorded in many other countries, including the UK and the US. 

Researchers did not find losing weight improved the men’s sperm motility, a term for how efficiently they ‘swim’, or the volume of sperm produced. 

NHS data from 2019 indicates 41 per cent of men in England are overweight, and 27 per cent are obese. The figures are similar in the US.

Low sperm counts are deemed a factor for about a third of couples struggling to get pregnant in the UK. 

Obesity has previously been suggested to lower men’s testosterone levels, affecting their ability to produce sperm.

The Danish study is just the latest research to highlight the link between obesity and low sperm counts.

Earlier this month scientists led by Utah University found fatter men in their 60s had lower sperm counts than slimmer individuals in the same age group.


The most common cause of infertility in men is poor-quality semen, the fluid containing sperm that’s ejaculated during sex.

Possible reasons for abnormal semen include:

  • a lack of sperm – you may have a very low sperm count or no sperm at all
  • sperm that aren’t moving properly – this will make it harder for sperm to swim to the egg
  • abnormal sperm – sperm can sometimes be an abnormal shape, making it harder for them to move and fertilise an egg

Many cases of abnormal semen are unexplained.

There’s a link between increased temperature of the scrotum and reduced semen quality, but it’s uncertain whether wearing loose-fitting underwear improves fertility.


The testicles produce and store sperm. If they’re damaged, it can seriously affect the quality of your semen.

This can happen as a result of:

  • an infection of your testicles
  • testicular cancer
  • testicular surgery
  • a problem with your testicles you were born with (a congenital defect)
  • when one or both testicles hasn’t descended into the scrotum, the loose sac of skin that contains your testicles (undescended testicles)
  • injury to your testicles


Some men choose to have a vasectomy if they don’t want children or any more children.

It involves cutting and sealing off the tubes that carry sperm out of your testicles (the vas deferens) so your semen will no longer contain any sperm.

A vasectomy can be reversed, but reversals aren’t usually successful. 


Hypogonadism is an abnormally low level of testosterone, the male sex hormone involved in making sperm.

It could be caused by a tumour, taking illegal drugs, or Klinefelter syndrome, a rare syndrome where a man is born with an extra female chromosome.

Medicines and drugs

Certain types of medicines can sometimes cause infertility problems.

These medicines are listed below:

  • sulfasalazine – an anti-inflammatory medicine used to treat conditions such as Crohn’s disease and rheumatoid arthritis; sulfasalazine can decrease the number of sperm, but its effects are temporary and your sperm count should return to normal when you stop taking it
  • anabolic steroids – are often used illegally to build muscle and improve athletic performance; long-term abuse of anabolic steroids can reduce sperm count and sperm mobility
  • chemotherapy – medicines used in chemotherapy can sometimes severely reduce sperm production
  • herbal remedies – some herbal remedies, such as root extracts of the Chinese herb Tripterygium wilfordii, can affect the production of sperm or reduce the size of your testicles
  • illegal drugs, such as marijuana and cocaine, can also affect semen quality.

Source: NHS 

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