How not to gain too much weight during pregnancy

Pregnancy weight gain
There is no agreement on the exact amount of weight to gain while pregnant, but there are guidelines

Gain too much weight during pregnancy and you run the increased risk of gestational diabetes, early labour and pre-eclampsia. Yet severe weight loss can be associated with an increased risk of autism and cardiovascular disease in your child. So what are the facts?

How much weight is it recommended to gain during pregnancy?

No two pregnancies are the same – and for every woman who sees it as a glorious period in which to finally indulge in all the food she has felt guilty about eating since puberty, there is someone else who is plagued by nausea and iron deficiency for the entire nine months.

Adding another layer of complexity is the fact that nobody seems to agree on exactly how much weight is safe to gain. The old line about eating for two is largely a myth (in general you only need an extra 200 calories a day in the third trimester) but not piling on enough pounds is – according to some studies – more dangerous than too many.

Equally, much of a woman’s “weight gain” is linked to the size of her foetus, the amniotic sac and the placenta, rather than her own fat deposits, and baby growth is usually the result of factors beyond our control including maternal age, gestational diabetes and genes.

Still, for women who start their pregnancy with a healthy BMI, the NHS recommends:

  • Gaining between 11.5-16kg (25-35lb) by the time of the birth

  • If you were underweight when you conceived, that can increase to 40lb (18kg)

  • While if your BMI was on the high side, then the NHS suggests putting on as little as 5-7kg (11-15lb)

Is it safe to lose weight when I’m pregnant?

“Severe weight loss in a mother is dangerous as it can be associated with increased autism and cardiovascular disease later in life for the baby,” says Dr Caitlin Dean, a GP specialising in women’s health. “Most women expect pregnancy sickness. But if symptoms interfere with your ability to eat and you find you are losing weight rapidly, see a doctor and demand medication.”

What are the risks if I gain too much weight?

Some women find nausea actually forces them to pile on the pounds. “When I had my first child, I had terrible morning sickness that only abated when I was in the act of eating cheese on toast,” says Miranda Dowell, a journalist who put on 4st 5lb (28kg) with her first child. “Unfortunately this led to very bad habits throughout the pregnancy, featuring stodgy comfort food – bacon and egg sandwiches for breakfast, pizza for lunch, and pudding every night.”

Like many first time mothers, Dowell assumed she would burn it off during breastfeeding, but while she lost the first 5kg relatively quickly, it took her a year and a lot of effort to shed the rest. “In my two subsequent pregnancies I didn’t make the same mistake and was very careful to stick to the recommended weight gain, eating less and exercising more, which worked,” she says.

“Because the Western world is dealing with obesity issues, we translate that into pregnancy and think that too much weight gain is going to make your kid really overweight later and so on,” says Emily Oster, the author of the bestselling guide Expecting Better. However, having spent a lot of time researching this, Oster found nothing compelling that indicated it would affect the child.

Still, excess weight can put you at a slightly higher risk for issues like gestational diabetes, early labour and preeclampsia, and even if you don’t develop any of these conditions, nobody wants to emerge on the other side of their pregnancy with a demanding newborn and a complex diet plan to negotiate.

How to maintain a healthy weight when pregnant


“My top tip would be to keep exercising,” says Marina Fogle, who runs an antenatal course called The Bump Class. “It’s important to be strong and fit for labour and you really don’t want to deny yourself food if you’re hungry. I always suggest women aim for 30 minutes of exercise four times a week and a mix of cardio and strength-based exercise.”

Fogle caveats this by saying you should stop as soon as you feel unwell or if you have any pain. In addition, impact exercise or anything where you are at risk of falling (cycling, for example) should be avoided, and working out in high temperatures is never a good idea. “You should be able to maintain a conversation and not be obviously sweating,” she says.


In terms of what you eat, the guidance is clear: don’t go on a calorie restrictive diet when pregnant or cut out any important food groups with the aim of losing weight. If you are putting on weight faster than you had hoped, scale back the sweets, fizzy drinks and white carbohydrates, but always keep eating three normal-sized or five small meals a day.

Many women find they crave calcium, so full-fat yogurt or a glass of milk is a good way to start the day. Sugar cravings are often the result of a lack of protein, and one way to avoid excess weight gain is by making sure every meal contains eggs, meat, fish or cheese, as it will help you avoid living off chocolate when you have a mid-morning slump. In a similar vein, it is important to refuel often with snacks like peanut butter and an apple or nuts.

“At the same time, women need to not feel the pressure to get back to their pre-birth body too fast,” notes Fogle. “It’s a complete myth that you’ll lose all the weight breastfeeding – some women take nine months to get back to their conception weight and some take years. But the first time you look at your naked body after you’ve given birth, don’t look at all the flaws – think of this amazing thing it has just done.”