Can Diet Cause Man-Boobs?


You might have seen very overweight men with flat chests and slim guys with chubby chests – some have them, some don’t – so why do some guys get ‘man-boobs’ and others don’t? And what does our diet have to do with it?

It seems increasingly common that men are developing a condition known as gynaecomastia (pronounced guy-knee-co-mast-ee-a), commonly known as ‘man-boobs’ or ‘moobs’.

Let’s not be dismissive about this, gynaecomastia can be very distressing for those men who have it.

Defining gynaecomastia

There are two main types:

  • Gynaecomastia – development of breast tissue behind the nipple that pushes the nipple outward. This is most common in teenage boys and usually (but not always) resolves itself. It can also develop later in life in up to half of all men.
  • Pseudogynaecomastia – development of fat tissue around the chest giving an appearance of breasts. This is most common in overweight men.

Gynaecomastia is graded according to its severity, with the most extreme forms giving the appearance of full female breasts. This can be seriously distressing for the man involved, and the only solution is often to have them removed surgically – and even then, there’s a small risk of recurrence.

Once breast tissue is formed, no exercise or diet will get rid of it. Only the fat can be reduced.

What causes it?

Gynaecomastia is caused by hormonal changes in the body. This can often be due to an underlying medical condition that affects one or more of the many glands in the body (particularly the pituitary or thyroid gland).

However, as men age, their levels of testosterone fall and as testosterone falls, oestrogen becomes the dominant sex hormone. Oestrogen is required to form and create breast tissue and many men over the age of 50 may start to form breasts.

Oestrogen-like hormone is also produced by fat tissue, so the more fat tissue you have, the more circulating oestrogen in your body.

Gynaecomastia has also been linked to:

    • Using anabolic steroids to aid muscle bulking, despite “cycling”
    • Liver damage, caused by excessive alcohol or following a poor diet
    • Different prescribed medications
    • Marijuana usage
    • Orchidectomy – having the testicles removed due to cancer or other medical reasons
    • Refeeding after a period of prolonged fasting
    • Essential oils, such as lavender and tea tree oil

Diet and exercise

First thing’s first – reduce body fat – we must consume fewer calories than our bodies use. Traditionally, this is achieved by burning more calories through physical activity and eating less (particularly junk) food.

That isn’t going to be breaking news for the majority of us! However, whilst there isn’t a vast body of evidence around compounds in our diet and the formation or reduction of gynaecomastia, there is a number of potential areas in which we could explore and see what difference, if any, they make.

As new ideas and new evidence comes in, I’ll ensure to update this blog post.

1. Phyto-oestrogens

Phyto-oestrogens are compounds found in plants (phyto) that potentially mimic the female hormone, oestrogen. There’s a lot of attention bought to phyto-oestrogens across the Web, and knowing what to trust and what not can be tricky.

Food that contains phyto-oestrogens is pretty extensive – it includes many plant-based proteins such as grains, beans, seeds and soya.

Food/Beverage Herb/Spice
 Carrots  Black cohosh
 Legumes (peas, beans, peanuts)  Chaste tree berry
 Soya (soya milk, tofu, tempeh)  Dong quai
 Coffee, tea  Evening primrose
 Brocolli  Licorice root
 Oranges, apples, pomegranates  Red clover
 Linseeds, sesame seeds  Mint
 Oats, barley, rice  Ginseng
Alfalfa, mung beans  Fennel
 Beer  Anise

As a nutritionist, I would be very reluctant to advise anyone to run away with this list and start avoiding the whole lot! We need to look at them and work out which ones may be more problematic than others.

Phyto-oestrogens are clearly abundant in our food sources, so can they really cause gynaecomastia? Let’s look at the evidence.

The most observed of all the phyto-oestrogens is a compound known as isoflavones. This is one of three of the most powerful properties within this class of compounds thought to influence our hormone profile.

This does not mean that other compounds have no significance, it just means no one yet has studied the link!

Isoflavones are found in soya and red clover, and it has been suggested that they have a feminising effect on men, because they raise oestrogen levels in the blood.

Studies to date have not been able to support this, but there is some evidence that this could well be due to individual variations in our sensitivity to isoflavones. In particular, we have to note that many studies have been conducted on Asian men, who have been exposed to soya in their diet from infancy and for many generations too (adaptations thus inherited from family line to family line).

It is possible that there are ethnic variations that have allowed Asian males to process isoflavones differently to men from Europe and America where soya is not a traditional dietary feature.

Many studies have also been performed on animals, and that does not always translate well to human physiology.

However, not all soya products are equal! The processing methods used to create soya-based products can remove a lot of the isoflavones – alcohol (ethanol) extraction removes most of the isoflavones, and this maybe the most common way of processing soya to make soya concentrate or soya isolate.

Fermenting soya to make the product tempeh, a meat-substitute commonly used in Indonesian cooking, also substantially reduces the isoflavones.

So most of the soya products are probably not going to cause any issues, and we need to remember that isoflavones are not bad! In fact, there is some evidence that they could protect against prostate cancer. So there’s always pros and cons with removing foods from our diets.

For now, consuming soya products in moderation is probably the way to go, and cut soya lattes down to an occasional treat.

2. Zinc

If there’s such a thing as a man’s mineral, it’s zinc! Zinc is necessary to make the hormone, testosterone. As we get older, our levels of testosterone drop – as do many other things in life!

So ageing may place a greater need for zinc in our diet.

If you exercise, whether that’s through aerobic work such as running, cycling or swimming, or weight-bearing gym work, there’s limited evidence to suggest that the inflammatory processes involved in during and post exercise may place a higher demand for zinc.

As mentioned in a previous post on zinc, men’s demand for zinc is already higher than women’s due to the prostate gland requiring zinc to make semen.

3. Vitamin D

Vitamin D, or the sunshine vitamin, is noted to be important for a healthy immune system. But it’s also been noted to have an effect on men’s testosterone status.

Men with low vitamin D status have been found to have low testosterone levels. Therefore, there is possibly a seasonal variation for men who live in areas of the world where many months of the year see very little natural daylight.

There haven’t been many studies looking at the potential of vitamin D supplementation on testosterone levels, but some studies suggest that it could help.

4. Fats

Firstly, unless medically indicated, men shouldn’t pursue very low fat diets. Low fat diets have been shown in some studies to reduce the production of testosterone. However, consuming high fat does not appear to impact upon testosterone levels in a positive or negative way.

Some websites suggest that consuming saturated fats or omega-3 fats will help enhance testosterone levels, but there is little scientific evidence for this.

Certainly, avoiding transfats (often found in processed foods and constantly reheated fat for deep frying) will benefit testosterone levels. So forget the Scottish diet of deep-fried pizza!

There’s also very limited data regarding avoiding high fat dairy products such as full-fat cheese and yoghurt. Studies are seriously lacking in this field, so don’t quote me, but there could be a link between dairy produce and low testosterone in men.

This is possibly due to the availability of oestrogens in cow’s milk.

So the bottom line here is not all fat is created equal, and until better studies come out looking at different types of fat and testosterone/oestrogen balance – treat articles written by non-technical people with a huge pinch of salt.

5. Alcohol and refined carbs

Moderating alcohol is really important in ensuring proper testosterone production and avoiding or slowing down the formation of gynaecomastia.

In a large Danish study, it was shown that moderate alcohol consumption increases testosterone production, but the flip side is that it negatively impacts sperm count! However, long term alcohol abuse does reduce testosterone.

We also know that alcohol can cause damage to the liver by increasing the fat that accumulates in it (a condition known as fatty liver disease). And so can a diet high in refined carbohydrates and processed foods. Fatty liver influences the causes of insulin resistance, and insulin resistance is correlated with low testosterone.

Which comes first, low testosterone or insulin resistance is yet to be determined, but certainly men with type 2 diabetes have lower testosterone are at greater risk of gynaecomastia.

The liver is necessary for the clearance of oestrogen, and if it is unable to do its job effectively, oestrogen will accumulate. Top this with phyto-oestrogen in beer, and the risk of gynaecomastia potentially increases.

So moderate alcohol, exercise more and keep refined sugars to a minimum.

Last word

Lifestyle can have a profound effect on whether or not gynaecomastia will develop or return.

Looking after yourself through diet and exercise, avoiding extreme stress, drinking alcohol moderately, avoiding refined sugars and transfats (keep the junk food down to special events), not forgetting your vitamin D, will all help keep our hormones in balance.

Regarding milk, soya, beer, flax and anything else you hear causing gynaecomastia – the evidence isn’t there. It may have an effect on some men, but not all. And this is a problem with nutrition – we’re talking about complex interplays between genetics and food compounds (and other environmental factors).

Picture Credit

Man with gynaecomastia by Dr Mordcai Blau – via Wikipaedia Commons


So what do you think?

This site uses Akismet to reduce spam. Learn how your comment data is processed.