Whether it's to bulk up muscles or lose weight, many people choose to eat a high-protein diet. If you are experiencing diarrhea while on a high-protein diet, you might wonder if too much protein is the cause.
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 the distress. Consuming a great deal of dairy to reach a protein target may lead to diarrhea in sensitive individuals and can cause upset 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 labels to be sure. Yogurt, especially Greek yogurt, is a wonderful source of protein and usually is easier to digest since it has been fermented.
Another consideration is that when you eat too much protein, your intake of other nutrients decreases. 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 stools.
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.
Protein ideally should account for 10 to 35 percent of your daily caloric intake, which is a pretty broad range. If you go beyond that range, you might run into trouble. 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.
- “Practical Applications in Sports Nutrition (2nd ed.)”; Heather Fink, et al.; 2009
- Whey Protein Institute; Whey Protein FAQ's
- Health News Digest; Vomiting, Diarrhea and Constipation – It Happens; Jo Ann Heslin; January 2010
- National Digestive Diseases Information Clearinghouse: Diarrhea