When you're following a low-carb diet, stomach pain, gas and bloating can be a problem. Anytime you make a big change to your diet, you risk some gastrointestinal upset while your body adapts to the change. However, if you continue to be gassy on keto, it likely has to do with something you're eating or something you're not eating. One common culprit is a lack of fiber, resulting in constipation.
Low-carb diets come in many varieties, limiting daily carb intake to below 100 grams, 50 grams, 30 grams — or even 20 grams. The popular ketogenic diet is on the lower end of that scale, and it's the one that usually causes the most problems. On a keto diet, you might be getting as few as 5 percent of your calories from carbohydrates. The average diet contains about 2,000 calories per day, so that's only 100 calories — or 25 grams of carbs — a day. With such a low limit, many people find it hard to get enough dietary fiber, the part of plant foods that helps normalize digestion.
Missing Out on Fiber
Current dietary recommendations encourage men to get 38 grams of fiber each day and women to get 25 grams of fiber daily. Fiber is found only in plant foods such as whole-grain bread, broccoli, oats and sweet potatoes. Your body doesn't digest or absorb fiber; it moves through your digestive system relatively unchanged, adding bulk to your stool and helping you empty your bowels more frequently and easily. Fiber also has other health benefits, including providing satiety, aiding weight management and helping control cholesterol levels.
Constipation and Keto Stomach Pain
Diets low in fiber often result in constipation, making it hard to pass stool. Typically, constipation is defined as having three or fewer bowel movements per week. Symptoms include straining to have a bowel movement, abdominal pain and the inability to pass gas, which can lead to bloating. On keto, stomach pain is often a result of constipation. Not getting enough fiber in your diet is a primary cause of constipation, and adding more fiber is the first line of defense. Foods that are high in fiber are also often high in carbs, but not always.
Make Carbs Count
Many dieters think that, along with grains, they need to avoid vegetables on a low-carb diet, but that couldn't be further from the truth. Nonstarchy vegetables, such as spinach, broccoli, cauliflower and zucchini, are nutrient-rich, low in carbs and high in fiber. When you take into account the net carb value — carbs minus fiber — these veggies fit perfectly within your daily carb budget:
Check out some of the carb counts in nonstarchy vegetables:
Vegetables are your best bet for low-carb fiber sources on a keto diet because fruits are often high in sugar. You can get all the fiber and nutrients you need from vegetables without eating fruit. However, there is one exception. With 1.5 grams of net carbs and more than 14 grams of healthy fats per half, avocado is the perfect keto fruit.
The Problem May Persist
Adding more vegetables will likely improve your digestive symptoms if you haven't been eating enough fiber. Keep in mind that there is an adjustment period while your body gets used to the increase in fiber, and you may experience an increase in gas and bloating during this time.
Additionally, certain vegetables can cause gas and bloating. According to the International Foundation for Gastrointestinal Disorders, these vegetables are most likely to cause gas for some people:
- Brussels sprouts
- green peppers
Not everyone will experience gas after eating these foods. If you notice gas every time you eat a particular food, try cutting it out for one week, making no other changes to your diet. If your gas subsides, then it's a good idea to restrict that vegetable in your diet in the future.
- WebMD: The Down Low on Low-Carb Diets
- Mayo Clinic: Dietary fiber: Essential for a healthy diet
- National Academy of Medicine: Dietary Reference Intakes: Macronutrients
- Healthline: How to Calculate Net Carbs
- Cleveland Clinic: Gastrointestinal Disorders
- Diet Doctor: Low-Carb Fruits and Berries: The Best and the Worst
- USDA: National Nutrient Database: Broccoli, Raw
- USDA: National Nutrient Database: Spinach, Raw
- USDA: National Nutrient Database: Squash, Summer, Zucchini, Includes Skin, Raw
- USDA: National Nutrient Database: Cauliflower, Raw
- USDA: National Nutrient Database: Avocados, Raw, All Commercial Varieties
- International Foundation for Gastrointestinal Disorders: Tips on Controlling Gas