Protein contains building blocks for all the cells in your body. Sources of this important nutrient include meat, dairy, nuts, seeds, eggs, fish, poultry and beans. According to the U.S. Department of Agriculture, women who are moderately active should have five 0.5- to 1-ounce equivalents of protein daily, and men should aim for five to six 1-ounce equivalents daily. Examples of 1-ounce equivalents of protein include 1 ounce of cooked meat or poultry, one egg, 1/2 ounce of nuts and 1/4 cup of cooked beans. Whether it's to bulk up muscles or lose weight, many people choose to eat a high-protein diet. If you're experiencing diarrhea while you're on a high-protein diet, it could be that the amount or type of protein you're consuming is the cause.
Dairy Foods Sensitivity
Food sensitivities are a leading cause of diarrhea, and dairy products are among the more common culprits. Many people don't make enough of the digestive enzymes needed to digest the lactose in dairy, which leads to digestive distress. Consuming a great deal of dairy to reach a protein target may lead to diarrhea in sensitive individuals and can upset the digestive system in individuals who otherwise can process dairy just fine.
Whey protein is derived from milk and may contain lactose. Pure whey protein isolate contains a very small amount of lactose and should not cause any digestive upset. However, whey protein concentrates can contain a great deal of lactose, depending on the brand and formulation, so check product labels to be sure. Yogurt, especially Greek yogurt, is a good source of protein and is usually easier to digest because it has been fermented.
Fiber Intake Concerns
Another consideration is that when you eat too much protein, your lack of intake of other nutrients can lead to deficiencies in your diet, according to the Mayo Clinic. Sacrificing calories from healthy carbohydrates, such as whole grains, fruits and vegetables, means sacrificing fiber, the great colon equalizer. Fiber absorbs excess water in the intestines, so having insufficient fiber intake can result in watery stools. Try supplementing your high-protein diet with apples. Not only are they high in fiber, but they also contain a lot of pectin, which can help thicken the stools.
Avoid Fatty Foods
Many foods rich in protein are also high in fat. Unfortunately, high-fat meals can lead to diarrhea. If you get your protein from red meats, bacon, cheese or other fatty foods, this could be causing your trouble. Consuming leaner proteins, such as chicken, fish or legumes, may allow you to reach your protein target with less gastrointestinal distress.
Limit Your Protein
One of the simplest ways to determine whether a food is causing you trouble is to reduce or eliminate it from your diet. Try cutting your protein intake to the lower end of the recommended range and see if that solves the problem. If so, try slowly adding more protein back in while monitoring yourself for any developing problems. Chronic diarrhea may be indicative of a more serious problem, however, so talk to your doctor if altering your diet does not eliminate the symptoms.