While it’s a bit of an embarrassing topic, many people report that peanut butter causes them stomach issues and flatulence.
While it doesn’t cause issues for everyone, there are reasons that explain why peanut butter can make someone gassy.
I’m going to summarize these issues and provide links to further information if you’d like to explore further.
Table of Contents
Peanut Butter Has a Significant Amount of Fiber
In natural peanut butter (i.e. contains just peanuts), a 2 tablespoon (32 gram) serving contains:
- 210 calories
- 6 grams of carbohydrates
- 2 grams of fiber
While that’s not an extraordinarily high amount, it’s not that uncommon to eat more than 2 tablespoons at a time.
Chemically speaking, fiber is a type of carbohydrate that’s very difficult for our body to extract energy from (i.e. digest). It gets fermented in the large intestine, which produces gas as a byproduct.
The fiber content of peanut butter shouldn’t be an issue for most people in small amounts, but can cause gas if you’re eating a lot of it.
Some Peanut Butters Have Hydrogenated Vegetable Oil
There are 2 types of peanut butter:
- Natural peanut butter – These only contain peanuts as ingredients
- More processed peanut butters – Most often, these contain added sugars and oils.
For example, JIF’s creamy peanut butter has the following ingredients list:
Roasted Peanuts, Sugar, Contains 2% Or Less Of: Molasses, Fully Hydrogenated Vegetable Oils (Rapeseed And Soybean), Mono And Diglycerides, Salt.
Even though it’s a small amount (2% or less by weight), there are still hydrogenated vegetable oils added.
The issue with this is that hydrogenated vegetable oils contain trans fats. The nutrition label might say that there are “0 grams” of trans fats, but that’s just because the serving size is small and they’ve rounded down.
A ton of studies have shown the negative health effects of trans fats, which range from serious diseases, to general inflammation that can contribute towards flatulence.
While it’s likely not the biggest factor in causing gas, the trans fats in highly processed peanut butters can contribute to the issue.
Peanut Intolerance or Allergy
A peanut allergy or intolerance will often result in gas.
You probably already know if you’re allergic, but you can get tested if you want to rule it out.
On the other hand, intolerances are harder to diagnose. People with an intolerance to peanut butter don’t have an immune reaction to it, but can experience side effects like:
- Stomach discomfort
One important way to distinguish an allergy from intolerance is that allergy symptoms occur even after a small exposure to peanut butter. The symptoms from an intolerance will scale with the amount ingested.
How Common is a Peanut Intolerance?
This is a tough topic to study, but there are estimates that about 20% of people have an intolerance to some food.
Foods like peanuts and milk make up a significant portion of this 20%, but there’s no specific research available on peanut intolerances that I could find.
Peanut allergies are relatively common, and can develop at any point in your life. If you’re noticing other symptoms like itchiness (or even a spicy taste) after eating peanut butter, you may want to get tested for a peanut allergy.
Peanut Butter Can Contain Added Fructose
Certain sugars are hard for our bodies to digest, so they end up fermenting in the intestines, which is how “gas” is formed. This includes sugars like:
- Lactose (if intolerant)
Natural peanut butter doesn’t have much sugar in it, but the cheap highly processed peanut butter has a significant amount of added sugar in it.
Added sugar is typically in the form of cane sugar, which is almost entirely sucrose.
Sucrose is composed of a 50/50 split of glucose and fructose. So while the glucose is easy for the body to digest, the fructose is not.
Research has shown that for many people (although not all), fructose causes flatulence.
Processed peanut butter is more likely to cause gas than plain “natural” peanut butter, as certain sugars that are commonly added can cause gas in some people.
Summary: Does Peanut Butter Cause Gas
While it doesn’t cause gas for everyone, there are some valid reasons why peanut butter can make some people gassy.
In order to avoid issues:
- Stick to natural peanut butter without added hydrogenated fats and sugars
- Get checked for an allergy if you suspect one
- Test having smaller portions