The Study
Brown fat-associated postprandial thermogenesis in humans: Different effects of isocaloric meals rich in carbohydrate, fat, and protein
This study found that when young men ate a carb-heavy meal, those with more brown fat burned a bit more energy — but it didn’t prove that the carbs made the brown fat work harder. It just showed they tended to go together.
Analysis score
Maximum 90 for a randomized controlled trial.
Where the score came from
Your body burns extra calories after eating — this is called thermogenesis. If you have lots of brown fat, your body burns way more calories after eating carbs, but not after eating protein or fat.
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 554 / 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.
- 1Yes — for people with active brown fat, eating carbs leads to nearly double the calorie burn compared to those without, which could help with weight management.
- 2After eating carbs: 4.35% of calories burned if you have lots of brown fat, 2.12% if you have little.
- 3After protein: 6.44% burned.
- 4After fat: 2.32% burned.
- 5Brown fat only helps with carbs.
Score breakdown, methodology, conflicts of interest, evidence analysis & raw study data
Publication
Journal
Frontiers in Nutrition
Year
2022
Authors
Sayuri Aita, Mami Matsushita, T. Yoneshiro, Takuya Hatano, T. Kameya, Iwao Ohkubo, M. Saito
Related Content
Claims (10)
Eating protein causes the body to burn more calories during digestion than eating the same amount of carbohydrates or fats, because breaking down and processing protein requires more energy.
The body uses more energy to process protein from food than it does to process carbohydrates or fats, resulting in greater heat production after eating protein.
In healthy young men, those with higher brown fat activity burn about twice as much energy after eating a carbohydrate-rich meal as those with lower brown fat activity, measured as 4.35% versus 2.12% of the calories consumed.
In healthy young men, eating a high-protein meal causes a higher increase in energy expenditure after eating compared to eating high-carbohydrate or high-fat meals, with specific percentages of 6.44%, 3.49%, and 2.32% of the meal's energy, respectively; this increase in energy expenditure is not linked to the activity of brown fat.
In healthy young men, eating a high-fat meal causes the smallest increase in energy expenditure compared to other nutrients, and this increase is not linked to brown fat activity, meaning brown fat does not play a major role in burning calories from fat.
In healthy young men, those with higher brown fat activity burn 2.23% more of the energy from a carbohydrate-rich meal as heat compared to those with lower brown fat activity.
Not medical advice. For informational purposes only. Always consult a qualified healthcare professional before making health decisions.