Can you use laxatives for weight loss?

Prescribed for constipation by medical professionals, and available over the counter, laxatives are designed to help people use the toilet.

One consequence of this can be weight loss – and a study last year of 13,000 people by Pediatrics found that dieters are increasingly turning to these small pills. The study found that 10.5pc of males aged 23 to 25 and 5.5pc of females within the same age group have used laxatives to try to lose weight.

They may be misguided in doing so. Using laxatives for weight loss is "like playing with fire", according to Nigel Denby, a dietitian specialising in treating Irritable Bowel Syndrome. And The National Eating Disorders Association (NEDA) agrees, calling the overuse of laxatives for weight loss the “The Laxative Myth” – because, quite simply, it doesn’t work.

The reason? Laxatives act on the large intestine, long after most food and calories have already been absorbed by the small intestine.

“The ‘weight-loss’ caused by a laxative-induced bowel movement contains little actual food, fat or calories," explains the association. "Instead, laxatives encourage the loss of water, minerals, electrolytes and indigestible fiber and wastes from the colon.”

How do laxatives work?

“There are three main types of laxatives,” dietitian Nigel Denby explains. “Some help to soften the stools and make them easier to pass. Others bulk the stool up by adding fibre, which again makes waste easier to pass out of the body.

"Then there are also laxatives which help to stimulate the gut muscles to do their job to move waste along the large intestine and out of the body.”

Do laxatives help you lose weight?

In a word? No. “Using laxatives to obtain a flat stomach is crazy,” says Nigel. “Of course, if you’ve been constipated, you’re definitely going to feel more comfortable once you’ve been to the loo.

"You might also find that opening your bowels relieves trapped wind and bloating but it won’t aid weight loss and routinely taking them is very dangerous.”

You may have read reports of people feeling ‘skinnier’ or having a flatter stomach after taking laxatives but this is purely down to a loss of water weight, which will immediately return once the body is rehydrated.

What happens when you routinely take laxatives?

There are a number of health concerns associated with the overuse of laxatives. These include:

Electrolyte imbalance

“Laxatives can lead to the body losing a lot of fluid, and with it, a lot of important electrolytes,” says Nigel Denby. These electrolytes control systems and functions in the body - including vital organs and your heart beat.  “When your electrolytes are out of balance, you can feel very ill and in extreme cases, it can be fatal.”

Dehydration

Because laxatives encourage a loss of water, users are at risk of dehydration. Severe dehydration can cause tremors, feelings of weakness, blurry vision, fainting and in extreme cases, untimely death.

Laxative dependency

“The body can become resistant to laxatives so if you’re overusing them, you’ll have to increase the dosage,” says Nigel. This can lead to laxative dependency. This is when the colon stops reacting to usual doses so larger amount are needed to produce bowel movements. In turn, this can lead to long lasting health problems, even after laxatives stop being used.

When is it OK to laxatives?

“Muscle stimulants should only really be used under the supervision of your GP or gastroenterologist,” says Nigel Denby.

“We all have occasional periods when we struggle to maintain our natural digestive rhythm– this might be when we are travelling, unwell and not so active or if we are feeling particularly stressed.

"For these odd occasions it’s fine to take a laxative. For some people who don’t or can't eat a lot fibre, regular use of fibre supplement laxatives can be helpful. It’s really important to drink plenty of fluid when using these sorts of products, as the fibre needs the fluid to make it swell, allow air into the stools thus making them soft and easier to pass. Taking additional fibre without extra fluid can make you feel even more constipated.”

How can I lose weight?

Healthy, sustainable weight loss takes time. Drastic measures such as crash and fad diets or overuse of laxatives are unsafe and often unsustainable. Visit your GP if you’re struggling to lose weight and read up on professional tips on weight loss.