Your gut microbes might be turning fiber into extra calories

Source: Arizona State University 

Title: Your gut microbes might be turning fiber into extra calories  

Date: October 24, 2025  

Page number:  

Author: Not given 

Link: https://www.sciencedaily.com/releases/2025/10/251024041819.htm 

Five W’s 

Who: Researchers at Arizona State University 

What: A study showing that some people’s gut microbes, specifically methane-producing microbes, turn fiber from high-fiber foods into extra calories, meaning these people absorb more energy from the same foods than others do.  

Where: United States 

When: The news was released October 24, 2025. 

Why: The researchers wanted to understand whether differences in people’s gut microbiomes might explain why some people absorb more calories, and maybe more energy, from the same high-fiber diets than others. 

Summary 

The study found that when people ate the same high-fiber diet, those whose gut microbiomes produced more methane ended up absorbing more energy from the fiber than people whose microbiomes produced little methane. When fiber breaks down in the gut, the microbes turn it into fatty acids that the body can use for energy. Then, some microbes use the hydrogen gas made during this process and turn it into methane. Because of that the body ends up breaking down more fiber and absorbing more calories from it. The researchers measured this using a device called a whole-room calorimeter. The results show how much methane a person produces can change how many calories they get from fiber-rich foods. This means a high-fiber diet may not work the same for everyone. 

My Opinion 

I find this study fascinating because it shows that “healthy eating” can be more different for each person than we think. Fiber-rich foods are usually recommended for everyone, but this research suggests that differences in gut might mean some people get more calories from them than others. That especially matters for people trying to lose weight or manage their calories, because it shows that the same diet could affect people differently. The article explains that “how much methane a person produces can influence how many calories they get from fiber-rich foods,” which is shocking to me because I eat a lot of fiber every day to reach my daily goal, and it seems to be working for me, but for some people it may have the opposite effect. At the same time, more research is needed, so I haven’t drawn any conclusions. The study is not saying fiber is “bad," in fact, the researchers still point out that fiber-rich foods have many health benefits. The main point is that maybe in the future, nutrition will have more “personalized gut-based diet plans.”