The Study
Influence of diets high and low in animal fat on bowel habit, gastrointestinal transit time, fecal microflora, bile acid, and fat excretion.
This study looked at how eating more or less animal fat changed things in the poop of just six healthy young men over a month. Because it only tested a tiny group and didn't use strict scientific controls like random assignment or blind testing, it can only show that fat intake might be connected to changes in certain gut chemicals. It cannot prove that eating fat actually causes those changes or affects disease risk.
Analysis score
Maximum 44 for a cross-sectional study.
Where the score came from
Researchers tested how eating a lot of animal fat versus a little affects digestion and waste in healthy young men over a month.
Where does this study sit?
Reviews of RCTs (Meta-analyses)
Max 100Randomized Trials
Max 90Reviews of Cohort Studies
Max 85Cohort Studies
Max 72Reviews of Case-Control Studies
Max 63Case-Control Studies
Max 58Cross-Sectional & Case Series
Max 50Expert Opinion
Max 544 / 100
Quality score
Snapshots of a population at a single point in time, or descriptions of small groups. Can identify correlations and prevalence, but cannot determine cause and effect.
Key takeaways
Summary
Based on the study abstract and findings.
- 1The extra fat and bile acids reaching the colon could theoretically increase colon cancer risk, but since gut movement and bacteria didn't change, other parts of the diet likely cause cancer-related gut changes.
- 2Eating 152g of fat daily instead of 62g daily caused about 320mg of bile acids and 3.1g of fat to pass through the body each day, compared to 140mg and 1.14g on the lower fat diet.
- 3Bowel movements, gut speed, and gut bacteria stayed the same.
Score breakdown, methodology, conflicts of interest, evidence analysis & raw study data
Publication
Journal
The Journal of clinical investigation
Year
1978
Authors
J. Cummings, H. Wiggins, D. J. Jenkins, H. Houston, T. Jivraj, B. Drasar, M. J. Hill
Related Content
Claims (5)
Eating a lot of animal fat (about 152 grams a day) for a month doesn't change the types of bacteria in your gut or the activity of certain gut enzymes in healthy young people. This suggests that changes in gut bacteria aren't the main reason why a high-fat diet affects the chemistry of your colon.
Eating a lot of animal fat makes your body excrete much more bile acid into your stool. This matters because too much bile acid in the colon is thought to increase the risk of developing bowel cancer.
Eating a lot of animal fat makes your body poop out more fat than usual. When healthy young adults ate about 152 grams of animal fat daily for a month, they excreted nearly three times as much fat in their stool compared to when they ate only 62 grams, showing that the gut can only absorb so much fat before the rest passes through.
Eating about 152 grams of animal fat a day for a month doesn't change how your digestive system works or how much you poop. This shows that just eating more fat isn't what causes changes in your gut movement, so other parts of your diet are probably responsible.
Your body can only absorb as much fat as your bile can handle. If you eat more fat than your bile can process, the extra fat just passes right through you and comes out in your stool.
Not medical advice. For informational purposes only. Always consult a qualified healthcare professional before making health decisions.