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

The keto diet is a very high fat, very low carb, moderate protein eating pattern. This way of eating induces a phenomenon called 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.

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. All three play important roles in health. However, when you follow the keto diet, your carbohydrate intake is drastically reduced.

Because carbohydrates like fruits and whole grains are some of the most common sources of fiber in the diet, transitioning to this low carb way of eating can lead to digestive issues like constipation.

Plus, some people may have a hard time transitioning to the very high fat content of the diet, which can also cause GI upset.

Not enough fiber

When you follow the keto diet, you typically only eat 20 to 50 grams (g) of carbs each day. This is far less than the Dietary Guidelines’ recommendation of 225 to 325 g of carbs, based on a 2,000-calorie diet.

Since higher carb, fiber-rich foods like fruits, whole grains, and starchy vegetables are off limits or significantly restricted for those following a keto diet, it can be a challenge to get enough fiber in the diet.

Fiber is essential for maintaining healthy bowel movements, so if a person following a keto diet is not consuming enough fiber from keto-friendly foods like nonstarchy vegetables, they may experience digestive issues like constipation.

Not consuming enough low carb, high fiber foods

While only about 5 to 10 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.

It’s best to aim for nutritious, high fiber, keto-friendly foods like:

  • nonstarchy vegetables
  • nuts
  • flax or chia seeds
  • limited amounts of berries

A person following a keto diet can enjoy small amounts of lower carb fruits like raspberries as long as their total carbohydrate intake remains under 50 g or whatever amount is needed to maintain ketosis.

Long-term constipation can lead to complications, including anal fissures, hemorrhoids, and abdominal pain. That’s why you do not 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.
  • Add more fiber-rich foods to your diet, such as leafy greens, broccoli, nuts, seeds, 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 is not better after 3 weeks, be sure to make an appointment with a doctor. They can work with you to find the best treatment.

While over-the-counter stimulants may help, it’s best to talk with a 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 g, 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 do not provide much nutritional value. Also, they’re typically low in fiber, which you need to keep your gut in good working order.

It’s essential to make sure you’re regularly eating keto-friendly, high fiber foods like:

  • nonstarchy vegetables, including greens, broccoli, asparagus, and cauliflower
  • nuts and seeds
  • avocados
  • chia and flax seeds
  • unsweetened coconut

Finally, it’s important to make sure you drink enough water.

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 does not get better despite home remedies and treatments, it may be time to contact a doctor. They may recommend prescription medications or some dietary changes to help get your GI tract back in working order.