Constipation after a gastric sleeve: why it happens and what helps

Going to the bathroom less often is something many people notice after a gastric sleeve. It is usually not serious, but it can be uncomfortable and worrying. Knowing why it happens makes it easier to prevent it and to act early.

Why it happens

• You eat much less, so there is less food and fibre moving through your gut.
• Drinking enough is harder with a small stomach, and low fluid intake makes stool harder.
• Some medicines and supplements can slow the bowels, including opioid pain medicines and iron supplements.
• You may move less in the first weeks after surgery.
• Changes in routine, such as travel, or holding it in when you feel the urge, can play a part.

How common is it?

Research on bowel habits after a sleeve is limited, and results vary. In a study of 124 people who had a sleeve in the Czech Republic, about 1 in 3 already had constipation before surgery. Six months after surgery, constipation was not more common overall. Almost half of those who had it before improved, while about 1 in 5 of those who did not have it before had more trouble.

So constipation is common, but it is not a given, and it often gets better with simple steps.

What helps

• Sip fluids through the day, between meals, toward the goal your dietitian sets.
• Add fibre slowly as your eating stage allows: vegetables, fruit, beans, lentils and whole grains. More fibre needs more fluid, too.
• Walk every day. Regular physical activity may help relieve constipation.
• Try to go at the same time each day. About 15 to 45 minutes after breakfast often works, because eating helps the colon move.
• Go as soon as you feel the urge. Resting your feet on a small stool can make it easier.
• Do not stop your vitamins or iron on your own. If you think a supplement is the cause, ask your team about other options.

Stool softeners and laxatives

Your team may give you a stool softener to use if you need it in the first weeks. Use it the way they explained. Ask your team or pharmacist before you take any other laxative or fibre supplement: some are not a good fit right after surgery, and fibre products need extra fluid to work. Laxatives are meant for short-term use, as advised by a health professional.

If you need help often, tell your dietitian. Canadian guidelines note that a dietitian can help with food choices and the right amount of fibre when constipation is a problem after bariatric surgery.

When to call your team

Call your care team right away if you have constipation together with any of these:

• Constant or severe belly pain, or pain that is getting worse.
• Vomiting, or you cannot keep fluids down.
• You cannot pass gas.
• A fever.
• In the first days after surgery: no gas or bowel movement by day 3, or a lot of straining.

For black or bloody stools, vomiting blood, chest pain or trouble breathing, call 911 or go to the nearest emergency department.