Many people, particularly those with gut problems, complain about bloating when they eat fiber. It may seem trivial, but in some people, it’s really intense.
This presents a problem because fiber has many benefits. Fiber intake:
- Decreases inflammation in the gut
- Seals up the gut
- Helps control blood sugar and appetite
- Reduces the risk of cardiovascular disease and Cancer
- Likely helps promote a healthy circadian rhythm
These things are great if you tolerate fiber well. But if fiber leads to intense gas, and pain within a few hours, it’s hard to justify eating it.
A new study provides hope for people who want the benefits of fiber but want to avoid painful gas and bloating. The problem may not be the fiber, per se. It may be what you eat with it that’s the real culprit.

High fiber diets and bloating
The Omniheart study is a 3-diet study performed between 2003-2005 with the diet conditions. Each participant consumed 3 separate high-fiber diets for 6-weeks. One diet was high carbohydrate, one was high protein, and the other was high fat.
All 3 diets contained the same number of calories and all participants performed each diet separated by a 2-4 week washout period. Most importantly, they recorded gas and bloating at baseline and throughout each dietary period.
Accordingly, the researchers found that those eating a high fiber diet also high in protein had 40% more gas and bloating than those eating a high carbohydrate diet. But it’s important to point out that these diets were very low in saturated fat.
Regardless of that fact, I don’t think it would impact the results. There ‘s a simple mechanism that’s likely at play here. But we have to go back to the 4th grade science fair to jog our memory.
Proteins and fiber in the colon
Do you remember making fake volcanoes in elementary school? Forget about the paper mache construction of the volcano, let’s focus on the actual gusher.
You’d take baking soda and vinegar and combine the 2 in a container and FOOOM! Instant volcano. What you didn’t know, at the time, is this is rudimentary chemistry and create problems for you down the road.
When you mix an acid with a base, you get a reaction. In the case of vinegar and baking soda, you get a mini explosion. But what happens if the same thing occurs in the colon? You’d bloat.
But it’s not baking soda and vinegar in your colon. Instead, it’s short chain fatty acids created via the fermentation of fiber combining with ammonia created from excess proteins that enter the colon.
Proteins are the only macronutrient that contains nitrogen, and ammonia is nitrogen with 4 hydrogen. Coincidentally, there’s a ton of hydrogen in the colon.
So what you’d effectively get is a 4th grade science experiment happening in your colon. The result: painful gas and bloating.
Conclusion
If you’re someone who doesn’t do well with fiber, it’s a good idea to take a look at your protein intake. While there are benefits to both higher protein and fiber intake, they may not go well together. Fiber seems to provide a strong benefit to resilience in the gut while protein seems to help maintain muscle mass.
We’re all different genetically and other lifestyle factors play a role in the diet that works best for us. An individual approach to diet is best.
But finding a balance is key, and factors such as exercise, profession, and alcohol intake also are important. Ultimately, it’s up to you to decide which best fits your genetics and lifestyle.
Would it be fair to say that these individuals also have weak stomach acid, leading to undigested proteins entering the colon?
Not 100% sure… but my mind is nagging me that the enzymes needed to digest the starches are different from the ones that digest the proteins?.. and if so… in order for them to do their job, correctly.. the starch might have to wait to be digested .. and sit there fermenting at 98.6 or so degree temperature? or vice versa…and possibly some larger bits leak into the bloodstream due to inflammation etc?
Not sure what your question is, but starches and proteins are digested by different enzymes that are released from different organs in the digestive tract.
Mechanical and chemical breakdown happens to both, and sometimes in the same organ. I don’t worry about sane drinking of fluids with meals, you just can’t drink 2 L with every meal. The stomach is designed to accommodate fluids.
Ps.. forgot to mention that nothing is stated about any drinks that are ingested during the meal.. which would dilute the action of the enzymes as well, and the amount taken in would affect the result?
what about the fat group?
What do you mean what about the fat group?
Do these short chain fatty acids get created from only soluble fibre or insoluble too? In other words, can both soluble fibre+protein and insoluble fibre+protein cause bloating?
Hey Bharat, I don’t like to say it’s exclusively soluble fiber, but that looks to be the case.
Keep in mind, eating too many carbohydrates can also increase SCFA.
Too many carbs in a meal you mean? How can one know if SCFA is causing an issue in the colon like when protein and fibre is combined? Bloating or gas is the common sign?
Even throughout the day. Any carbs you don’t absorb are free game for your microbiome.