Arizona State University researchers report that people who produce more methane in the gut tend to extract more metabolizable energy from a fiber‑rich diet, pointing to microbiome differences that could inform personalized nutrition. The work appears in The ISME Journal (2025) and was highlighted by ASU on October 24, 2025.
A new analysis from Arizona State University links methane made by gut microbes to how efficiently people harvest energy from fiber. In a controlled feeding study, participants who produced more methane absorbed more calories on a fiber‑rich, whole‑foods diet than those who produced less, according to ASU and The ISME Journal. Methanogens—the archaea that consume hydrogen and release methane—were identified as key players in this process. (sciencedaily.com)
The research team compared two diets: a highly processed, low‑fiber Western‑style diet and a whole‑foods, fiber‑rich “microbiome enhancer diet” with similar proportions of carbohydrates, protein and fat. To capture metabolism and gas output with unusual precision, participants stayed in whole‑room calorimeters—sealed, hotel‑like chambers—during inpatient phases. Each person spent six days in the calorimeter on each diet as part of the broader randomized crossover trial run with the AdventHealth Translational Research Institute. (sciencedaily.com)
Across the study, nearly all participants absorbed fewer calories on the fiber‑rich diet than on the processed diet. But among those on the fiber‑rich plan, higher methane production was associated with greater metabolizable energy, narrowing the calorie‑absorption gap for “high methane” producers. The journal article reports that high methane producers had higher metabolizable energy specifically on the fiber‑rich diet. (sciencedaily.com)
Biochemically, the pattern tracked with microbial metabolites: high methane producers showed higher serum propionate, a short‑chain fatty acid (SCFA) that humans can absorb for energy. Notably, the ISME paper did not find a corresponding rise in fecal SCFAs, suggesting increased production and uptake rather than accumulation in stool. (academic.oup.com)
“The human body itself doesn’t make methane, only the microbes do. So we suggested it can be a biomarker that signals efficient microbial production of short‑chain fatty acids,” said corresponding author Rosa (Rosy) Krajmalnik‑Brown, who directs ASU’s Biodesign Center for Health Through Microbiomes. Lead author Blake Dirks added that the findings help explain why people on the same diet can respond differently. (sciencedaily.com)
The work builds on a rigorously controlled parent trial showing that a fiber‑rich, microbiome‑enhancing diet reduces the calories people absorb compared with a processed Western diet, even when total calories and macronutrient ratios are matched. The trial used repeated six‑day calorimetry blocks per diet to quantify energy intake, expenditure and output. (pmc.ncbi.nlm.nih.gov)
The study was conducted with the AdventHealth Translational Research Institute. Co‑authors include Taylor L. Davis, Elvis A. Carnero, Karen D. Corbin, Steven R. Smith and Bruce E. Rittmann. The project was funded by the National Institute of Diabetes and Digestive and Kidney Diseases. (sciencedaily.com)
Publication note: The findings are reported in The ISME Journal (Volume 19, Issue 1, 2025); ASU highlighted the research in a news release on October 24, 2025. (academic.oup.com)