When you put on an unexpected few pounds, it can be tempting to blame it on your hormones rather than a recent spate of takeaways.
But it may not be just a lame excuse, for experts say there are times when our hormones – chemicals that are essential for growth, development and fertility – can go haywire, leading to a change in body shape.
And, depending on which hormone is involved, it can affect where the weight piles on or falls off.
From a ballooning waistline to extra pounds all over, or a dramatic drop in weight, here’s how hormones could be the reason behind your changing physical appearance…
FAT ALL OVER
Struggling to shift the pounds that have slowly crept on all over your body?
Feeling sluggish, more tired than usual?
This could be a sign that you have an underactive thyroid, a fairly common condition, particularly in women (about 3 per cent of women aged 20 to 40 are affected).
Also known as hypothyroidism, it occurs when the thyroid gland in the neck doesn’t produce enough of the hormone thyroxine, which controls how much energy your body produces, among other functions.
As Dr Tara Kearney, a consultant endocrinologist at Salford Royal NHS Foundation Trust, explains: ‘It often gets missed until it’s fairly extreme because the symptoms can be vague.
‘People may think they’re putting on weight because they are getting older, and blame feeling a bit flat on life not being great.
‘As it happens slowly, you often don’t notice it creeping on you over the years.’
This weight gain is known as ‘global’, ie, it occurs all over, like the Michelin man.
Other symptoms of underactive thyroid include dry skin and hair – in extreme cases, patients may fall into a coma because it can cause the metabolism to slow down to such an extent that the brain stops working.
But Dr Kearney warns: ‘Often people come to clinic absolutely convinced they have a hormone imbalance, and when you do blood tests they are normal.’ Then you will have to take a hard look at your diet.
When a man develops the kind of curves Beyoncé would be proud of, it could be down to an excess of the female sex hormone oestrogen (all men produce some oestrogen, just as all women produce testosterone).
Gynecomastia, as it is known, is most commonly a side-effect of certain drugs, such as those used to treat stomach ulcers.
Men being treated for prostate cancer may develop breasts if they are taking androgen deprivation therapy – drugs that lower levels of the male hormone.
Gynecomastia can also occur as a result of liver failure, because the liver helps to metabolise and remove oestrogen.
Sometimes newborns and pubescent boys develop breasts as a result of a rapid change in sex hormones in the body – the breast tissue responds to a temporary exposure to too much oestrogen.
‘If you have too much oestrogen and your breast tissue is not used to seeing that oestrogen it may grow a bit, then subside,’ says Dr Kearney.
It is possible to have man boobs and be otherwise normal weight.
However, if a man on the beach looks as if he could benefit from the support of a bikini but is also hefty, it is being overweight rather than hormones that is to blame.
‘Man boobs are generally a result of plain fat, much like having a big belly,’ says Dr Kearney.
BIG BELLY, THIN ARMS AND LEGS
Looking like a ‘lemon on a toothpick’ – with a fat middle and skinny limbs – can be a sign of Cushing’s syndrome, a condition caused when the adrenal glands (which sit above the kidneys) produce too much cortisol.
‘Cortisol is a stress hormone that helps you hang on to your calories in case you need them – in evolutionary terms this was to prepare you for battle,’ says Dr Kearney.
Typical signs of Cushing’s include a large, round face, ruddy complexion and often a pad of fat – known as a ‘buffalo hump’ – between the shoulder blades.
Exactly why fat is distributed in this way is not clear but the extra fat round the middle is emphasised by the arms and legs getting thinner.
‘You get a lot of muscle wasting on the limbs. You seem to inappropriately burn up protein despite having lots of fat to rely on – so your thin arms and legs make it look as if you have more elsewhere,’ says Dr Kearney.
People can become ‘Cushingoid’ as a side-effect of taking steroids to treat severe asthma, ulcerative colitis or rheumatoid arthritis.
Cushing’s can also occur spontaneously but this is rare, affecting only about 20 to 40 people in every million.
A deficiency of growth hormone can also cause people to put on fat around the middle and lose bulk in the arms and legs. This can occur as a result of damage to the pituitary gland (located at the base of the brain), perhaps because of a tumour or radiotherapy for cancer.
‘The most effective way of conserving energy is to put fat around the organs in the tummy, but for people with Cushing’s or growth hormone deficiency, you are storing energy at a faster rate than you are burning it off, so you get fatter and fatter,’ explains Dr Kearney.
Extra fat round the middle predisposes you to cardiovascular disease, so patients also have a higher risk of heart attacks and strokes.