The ketogenic (or keto) diet continues to be one of the most popular dieting trends in the United States. This is mostly because clinical evidence shows it may help you lose weight and improve your health.

By drastically cutting back on carbohydrates and replacing those carbs with foods that are high in fat or protein, this diet can put your body into a state of ketosis.

When you’re in ketosis, your body burns fat instead of glucose (usually from carbs) for energy.

While the keto diet may help you burn fat, there can also be side effects. Many of these side effects are related to your gastrointestinal (GI) tract reacting to the absence of carbs.

One such side effect is constipation. This means that you have three or fewer bowel movements per week. Being constipated may also make your stools hard and lumpy, and difficult to pass.

So, why does this happen? Read on to find out what causes constipation with the keto diet, and what you can do to prevent it.

If the keto diet is supposed to improve your health, what causes your GI tract to react to this high-fat, low-carb way of eating? Here are some of the main reasons you may experience constipation while following the keto diet:

Adjustment to fewer carbs and more fat

Our bodies are designed to digest three macronutrients: carbs, fats, and protein. While eating too many carbs typically isn’t recommended if you’re trying to lose weight, cutting back on your carb intake too quickly can put your GI tract into a stressed state.

When you switch to a keto diet, your body has to adjust from digesting a heavy load of carbs to digesting a lot of fat. It can take a while for your gut to get used to breaking down more fat than it’s been used to.

Not enough fiber

When you follow the keto diet, you typically only eat 20 to 50 grams of carbs each day. This is far less than the dietary guidelines recommendation of 225 to 325 grams of carbs, based on a 2,000 calorie diet.

Also, healthy carbs such as fruits and whole grains contain fiber. When you cut back on these foods, you’re no longer getting the normal “bulk” in your diet that you need to keep your bowel movements regular.

Eating low-fiber instead of high-fiber carbs

While only about 5 percent of the food you eat on the keto diet is made up of carbs, the key is to make sure you’re eating the right kind. Aim for healthy, nutritious, high-fiber carbs like fruits, vegetables, and whole grains.

If you only eat low-fiber carbs, like white bread, white rice, or sugary goods, you likely won’t be getting the fiber you need to move food through your GI tract.

Long-term constipation can lead to complications, including anal fissures, hemorrhoids, and abdominal pain. That’s why you don’t want it to go unchecked for too long.

If you’re new to the keto diet, you may find that your constipation only lasts a few days to a few weeks. As your body adjusts to digesting more fats and fewer carbs, your constipation may get better.

If your constipation continues to be an issue, try one of these home remedies:

  • Drink more water.
  • Temporarily add more fiber-rich foods into your diet, such as whole grains, legumes, and berries.
  • Go for a brisk walk after meals.
  • Try bowel training, a method where you pass stools at the same time every day.

If your constipation isn’t better after three weeks, be sure to make an appointment to talk with your doctor. They can work with you to find the best treatment.

While over-the-counter stimulants may help, make sure you talk to your doctor before taking any fiber supplements or laxatives. Some of these products are high in carbs, which can derail your efforts on the keto diet.

One way you can prevent constipation is by introducing the keto diet gradually.

For instance, you can start off with a daily carb intake on the higher end, around 50 grams, and then slowly reduce your carb intake as your digestive system adjusts.

This approach can take a bit longer for you to reach ketosis. But you may be more likely to stick with the diet if you have fewer side effects.

Another way to prevent constipation with the keto diet is to make sure the fats and proteins you eat come from whole foods. Eating a lot of processed meals and fast foods can put extra stress on your GI system.

Processed foods usually don’t provide much nutritional value. Also, they’re typically low in fiber, which you need to keep your gut in good working order.

Finally, it’s important to make sure you drink enough water. You need a minimum of eight glasses of water a day to stay hydrated and to help remove toxins from your body.

The keto diet may initially cause constipation as your body gets used to digesting fewer carbs and more fat. But as your GI tract adjusts to this way of eating, you may find that it becomes less of an issue.

You can also reduce your risk of constipation by eating more whole, high-fiber foods to help keep your bowels moving.

If your constipation doesn’t get better, despite home remedies and treatments, it may be time to see your doctor. They may recommend prescription medications or some dietary changes to help get your GI tract back in working order.