To start, there are many reasons as to why increasing protein can sometimes cause digestive discomfort, particularly for people with IBS or sensitive digestion.

However, first and foremost I want to explain that protein itself isn’t usually the problem for people. The protein source itself can definitely matter for some individuals, but typically symptoms are often related to other ingredients found in protein products, such as sugar alcohols like erythritol, maltitol, sorbitol, or xylitol; dietary fibers like chicory root or inulin (which is primarily sourced from chicory root); excessive amounts of gums or thickening agents like xanthan gum, carrageenan, guar gum, cellulose gum, etc.; artificial sweeteners like sucralose, saccharin, and aspartame; high lactose content in some dairy proteins; large amounts of fiber per serving (10g+); high-FODMAP mix-ins like milk, certain fruits (apple, mango, pear, etc.) or honey; or high-fat ingredients that slow stomach emptying. These have all been shown to have various effects on individuals with IBS or a sensitive digestion (1-5).

Colonic protein fermentation byproducts, serving size, and visceral hypersensitivity are other reasons that can lead to digestive discomfort when increasing protein intake. When protein intake exceeds the small intestine’s absorptive capacity, undigested protein then reaches the colon where fermentation from gut microbes generates potentially harmful byproducts (metabolites) such as ammonia, hydrogen sulfide (H2S), phenols, and various gases. These byproducts can upset the gastrointestinal system in various ways, leading to unwanted symptoms like bloating, increased gas, stomach pain, reflux, etc. (6). Individuals with IBS are particularly vulnerable to digestive discomfort from increased protein intake because of something called visceral hypersensitivity. These disproportionate symptoms of visceral hypersensitivity occur because of lower sensation thresholds in response to bowel distention even with normal volumes of gas or fluid (1,7). 

I often recommend that clients gradually increase their protein intake over time and do it in a way where it is also spread throughout the day instead of relying on large, heavy meals.

These are two key starting places. I like to increase through weekly increments. This allows the individual to build at an easy pace while gaining insight and connection with their body to better understand if the serving size is too much for the individual and pinpoint what proteins may be problematic for their digestive system.

The American Gastroenterological Association recommends regular meals, avoiding large gaps between eating, and making dietary changes incrementally with monitoring (8). A framework for increasing protein can look something like this: 

Small, consistent increases are often much better tolerated. It is also important to drink plenty of fluids, have balanced meals along with protein, chew food thoroughly and avoid introducing any other new foods simultaneously.

As mentioned previously, spreading protein throughout the day, such as over 4-5 meals/snacks, is also going to provide a better chance of tolerance because it reduces that chance for colonic protein fermentation. An example of this may look like:

As previously mentioned, there can be many reasons as to why symptoms may occur when increasing protein intake, so while it is important to note the protein(s) consumed, there are other areas to investigate as well. This is why taking a slow approach to increasing protein intake and utilizing a food and symptom journal during the process is so helpful.

• Serving size – how big was the serving size?
• Protein source – did you try a new or different protein source than usual?
• Were there added ingredients? If you used a powder or a protein-emphasized product (like protein bars, etc.) make sure to review the label for any sugar alcohols, chicory root, inulin, artificial sweeteners, high FODMAP foods, large amounts of added fiber, any colorants or gums, etc.
• Was there anything else you ate the protein with? Did you consume dairy or high FODMAP food sources with the protein source?

Understanding digestive symptoms after protein consumption is also incredibly helpful. Here are some other ways to isolate the offending variable:

• Timing: symptoms that occur within 30 minutes usually indicate gastric factors at play (like volume of food, the pace the food was eaten at, fat content, etc.). Symptoms in the range of 30 minutes to 2 hours may suggest small bowel factors (lactose, fructose malabsorption, etc.). Symptoms beyond 2 hours can suggest colonic fermentation or a potential sensitivity.
• Changing one variable at a time can help pinpoint underlying factors: 
  • Try switching the protein source (example – going from whey to a plant-based protein powder) while keeping everything else constant.
  • Reducing the serving size by half. If symptoms resolve, it was likely a dose-dependent issue.

Finding the right protein often requires considering the complete ingredient list, not just the grams of protein. Some of my recommendations when selecting protein-rich foods include finding lean, easily digestible proteins, like chicken breast, eggs (if tolerated), fish, high-quality tofu, and utilizing bone broth in recipes (like rice, soups/stews, pasta, etc.) or drinking it solo. When protein-rich foods may not be enough to meet needs or are too tough on the system, adding in a protein powder can be incredibly helpful. When looking for a quality protein powder, it’s important to consider:

As a registered dietitian, I recommend Better Blends as a great choice for many clients looking to increase protein intake in a gentle way while reducing risk for digestive symptoms. The protein powders are formulated with gut health and wellbeing in mind.

They contain quality yet minimal ingredients and are certified to be low FODMAP through rigorous testing. Some key ingredients include pea protein and organic brown rice protein as protein sources. Both of which are high-quality and easier-to-digest, leading to less risk of bloating or digestive discomfort.

They contain L-glutamine which is a conditionally essential amino acid that supports the immune system, digestive health, muscle recovery, brain health, and metabolic functions. L-glutamine is often a supplement that I recommend for individuals to support and heal their gut lining.

Potato fiber is another key ingredient that can help support digestion while avoiding excessive fermentability like other fibers. Individuals with sensitive digestion find it easier to tolerate. The total fiber in Better Blends is 3g which is considered a good source of fiber without being excessive.

Another ingredient to highlight in their protein powders is slippery elm bark, which has a long history of traditional use for soothing the digestive tract. It contains mucilage, a gel-like substance that can coat and soothe irritated issues. These blends provide a supportive way for many individuals with IBS and sensitive digestion as a way to meet protein needs without worry, unlike conventional blends that are often filled with poor quality protein sources, gums and fillers, artificial sweeteners and ingredients that oftentimes lead to digestive distress.

For individuals anxious about increasing protein intake, I recommend starting slow and taking small incremental steps. Start with small, well-tolerated protein sources and increase gradually. Distribute protein across multiple meals and choose products with minimal additives and no known FODMAP triggers like Better Blends. Using a food-symptom diary can also help build confidence through self-monitoring. When in doubt, reach out to a registered dietitian to help support you along your way.

1. Moshiree B., Drossman D., Shaukat, A. AGA Clinical Practice Update on Evaluation and Management of Belching, Abdominal Bloating, and Distention: Expert Review. Gastroenterology 2023;165:791-800. https://doi.org/10.1053/j.gastro.2023.04.039
2. Wang XJ, Camilleri M, Vanner S, Tuck C. Review article: biological mechanisms for symptom causation by individual FODMAP subgroups - the case for a more personalised approach to dietary restriction. Aliment Pharmacol Ther. 2019; 50: 517–529. https://doi.org/10.1111/apt.15419
3. Lenhart A, Chey WD. A Systematic Review of the Effects of Polyols on Gastrointestinal Health and Irritable Bowel Syndrome. Adv Nutr. 2017;8(4):587-596. Published 2017 Jul 14. doi:10.3945/an.117.015560
4. Rinninella E, Cintoni M, Raoul P, Gasbarrini A, Mele MC. Food Additives, Gut Microbiota, and Irritable Bowel Syndrome: A Hidden Track. Int J Environ Res Public Health. 2020;17(23):8816. Published 2020 Nov 27. doi:10.3390/ijerph17238816
5. Singh P, Lee A, Sheth NM, Chey WD. Chronic, Noninfectious Diarrhea: A Review. JAMA. 2026;335(14):1250–1262. doi:10.1001/jama.2026.0872
6. Yao, C.K., Muir, J.G. and Gibson, P.R. (2016), Review article: insights into colonic protein fermentation, its modulation and potential health implications. Aliment Pharmacol Ther, 43: 181-196. https://doi.org/10.1111/apt.13456
7. Chey WD, Kurlander J, Eswaran S. Irritable Bowel Syndrome: A Clinical Review. JAMA. 2015;313(9):949–958. doi:10.1001/jama.2015.0954
8. Chey, W., Hashash, J., Manning L., Chang L. AGA Clinical Practice Update on the Role of Diet in Irritable Bowel Syndrome: Expert Review. Gastroenterology, 2022; 162, 1737-1745.e5. https://doi.org/10.1053/j.gastro.2021.12.248

**Disclaimer: Oswald Digestive Clinic partnered with Better Blends to provide nutrition expertise and support during the formulation of Better Blends products. This partnership does not constitute medical advice, and individual results may vary. Please consult a qualified healthcare professional before making changes to your diet or nutrition routine.