Can constipation cause weight gain?

Constipation can leave you feeling bloated, heavier than usual, and wondering why the number on the scale suddenly jumped. But can constipation actually cause weight gain? Yes, temporarily — but it doesn’t directly cause you to gain body fat.

Constipation weight gain typically resolves once your bowel movements return to normal. Below, we’ll explain how much your weight can change from constipation, why it happens, and what can help get things moving again.

Yes, being constipated can make you gain weight temporarily — key word being temporarily. When you’re constipated, stool stays in your colon longer, so you’re carrying around more waste than usual. Constipation can also cause bloating and abdominal distension, making you feel or look heavier.

What constipation doesn’t do, though, is directly cause you to gain body fat. So, if the scale goes up when you haven’t pooped in a few days and drops again once you do, that change is likely from stool and normal fluid shifts rather than fat gain or loss. 

The same goes for chronic constipation. Chronic constipation and changes in body weight can sometimes occur together, but that doesn’t mean one is causing the other. Other factors, including diet, activity levels, medications, and certain health conditions, can affect both your weight and bowel habits.

Start your journey

Constipation does make you gain weight temporarily for a pretty straightforward reason: More waste is staying in your digestive tract than usual. But a few things can contribute to the change you see on the scale or in the mirror, including: 

• Stool buildup: When bowel movements slow down, stool spends more time in your colon before leaving your body. Until that stool passes, its weight is part of your total body weight. 

• Bloating and distension: Constipation and bloating often go hand in hand. Retained stool can interfere with how gas moves through the gut, while slower intestinal movement can cause your abdomen to look visibly fuller.

• Shared lifestyle or health factors: Sometimes constipation and weight gain have the same underlying contributor rather than one causing the other. For example, low activity levels, a poor diet, dehydration, and certain medications are associated with constipation and can also affect body weight.

There’s no set number of pounds you’ll gain from constipation; stool weight varies widely depending on factors like diet and fiber intake. One review found that healthy adults produced a median of about 128 grams (0.28 pounds) of stool per day, though there was a wide range.

That means going a few days without pooping can add some temporary weight, but there’s no evidence that constipation routinely causes meaningful weight gain on its own.

The best way to avoid temporary weight gain from constipation is to keep your bowel movements regular. Simple, everyday habits can support healthy digestion and reduce the risk of constipation.

Increase fiber intake

Fiber can help prevent and relieve constipation by adding bulk to stool, which helps it move through your digestive tract more regularly. Foods like fruits, vegetables, whole grains, beans, nuts, and seeds are good sources of fiber. Fiber supplements can also help; research found psyllium to be one of the better-supported options for constipation.

Just don’t go from zero to fiber hero overnight. Increasing your intake too quickly can cause gas and bloating, so it’s generally better to add fiber gradually.

Stay hydrated

Fluids help keep stool softer and easier to pass, especially when you’re eating more fiber. Guidelines on managing constipation recommend adequate hydration when increasing fiber intake.

That said, drinking extra water isn’t necessarily a constipation cure if you’re already well-hydrated. The goal is to consistently get enough fluid rather than forcing yourself to drink excessive amounts.

Move more

Regular movement may also help keep your bowels moving. That’s why exercise is commonly recommended as one of the first lifestyle fixes for constipation.

You don’t need an intense workout to get the potential benefits. Walking and other forms of regular physical activity can be a good place to start.

Consider an OTC laxative

If lifestyle changes aren’t cutting it, an over-the-counter (OTC) laxative may help. In particular, clinical guidelines recommend polyethylene glycol (like MiraLAX) for chronic constipation, and bisacodyl or sodium picosulfate (like Dulcolax) for short-term relief. 

Just keep in mind that while laxatives can help relieve constipation, they’re not a weight loss tool and won’t reduce body fat. It’s unsafe (and ineffective) to use them to lose weight. If you’re reaching for laxatives regularly or aren’t sure which type is best for you to relieve constipation, check with your healthcare provider.

If being constipated does make you gain weight, the goal is to treat the constipation, not the number on the scale. Once you start having regular bowel movements again, the extra weight from retained stool should resolve on its own.

Here’s where to start:

• Get back to the basics: Drink enough fluids, eat fiber-rich foods, and keep moving. These habits can help get your bowel movements back on track and lower your chances of becoming constipated again.

• Give it some time: You may not see the scale change immediately after a bowel movement. Your weight naturally shifts from day to day, so focus on how your symptoms are improving rather than on a specific number.

• Try an OTC treatment if needed: If lifestyle changes aren’t helping, an OTC laxative may provide relief.

• Skip laxatives for weight loss: Taking laxatives to try to lose weight won’t reduce body fat and can cause potentially dangerous side effects. If your goal is weight loss and management, there are safer, evidence-based approaches that can help, including following a healthy diet, exercising regularly, managing stress, and, if appropriate for you, weight loss medications such as Zepbound, Wegovy pen, the Wegovy pill, and Foundayo.

See if you qualify

An occasional bout of constipation usually isn’t cause for concern. 

But if it keeps happening, doesn’t improve with at-home treatment, or comes with unexplained weight changes, it’s worth checking in with a healthcare provider. That’s because chronic constipation can sometimes be related to medications or an underlying health condition, such as hypothyroidism or a digestive disorder.  

Seek medical care sooner if constipation comes with warning signs such as blood in your stool, persistent or severe abdominal pain, vomiting, fever, or unintentional weight loss. And if your weight continues to climb even after your constipation improves, talk to your provider — the change may have another cause that’s worth looking into.

While constipation can bump up the number on the scale temporarily, it doesn’t directly cause body fat gain. Here’s what to remember:

• When you’re constipated, retained stool can add to your body weight until you have a bowel movement.

• Constipation can also cause bloating and abdominal distension, which may make your stomach feel or look bigger.

• There’s no set amount of weight you’ll gain from being constipated, and larger changes on the scale may have other causes, such as fluid retention.

• Fiber, fluids, regular movement, and OTC laxatives when appropriate can help prevent or relieve constipation.

• If constipation persists, keeps coming back, or comes with symptoms like blood in your stool, severe abdominal pain, vomiting, or unexplained weight loss, contact a healthcare provider.