Overfed for two weeks. No significant fat gain.
A randomized, double-blind, placebo-controlled crossover pilot trial on the original Professor Nutz peanut butter. Published and peer-reviewed in 2020.
How the study worked.
Same people, two peanut butters, a lot of extra calories.
- Who6 healthy men
Non-obese, aged 25 to 35, not trying to lose or gain weight.
- DesignCrossover, double-blind
Randomized and placebo-controlled. Nobody knew which peanut butter they were eating.
- The overfeed+160g a day
Their usual daily calories, plus five extra servings (160g) of peanut butter every day.
- How long2 weeks each
Two weeks on regular peanut butter, two weeks on Professor Nutz, with a four-week washout in between.
- MeasuredDXA scans
Fat mass and lean mass by whole-body DXA scan, plus resting metabolism, before and after each phase.
- WhereTampa, Florida
Run by the Research Department of the Applied Science and Performance Institute.
Fat mass after two weeks.
Average change in fat mass, measured by DXA.
Fat mass rose significantly on regular peanut butter (+6.3%, p<0.05). On Professor Nutz the change (+0.26%) was not significant, and the percent change was significantly smaller than with regular peanut butter. Neither phase changed lean mass or resting metabolism significantly. Total body weight rose 1.15kg on regular and 0.40kg on Professor Nutz, a difference that was not statistically significant.
What it means. What it doesn't.
What it shows
- Overfeeding with regular peanut butter added about a kilo of fat in two weeks.
- The same overfeed with Professor Nutz produced no significant fat gain.
- Lean mass and resting metabolism held steady in both phases.
Keep in mind
- It was a pilot: six men, two weeks per phase. Bigger studies tell you more.
- It tested the original Professor Nutz peanut butter.
- The study was funded by AD-TPS Ltd. Digestibility varies from person to person.
Copycats copy labels. They can't copy a study.
Plenty of jars talk about low calories now. Ask to see their own published, peer-reviewed study. Ours is right here.
Sharp M, Stefan M, Wilson J, Reber D, Gheith R, Ottinger C, Lowery R. The effects of two weeks of overfeeding with peanut butter modified with cyclodextrins on body composition and metabolism: a double-blind, placebo-controlled, crossover, pilot trial. IP Journal of Nutrition, Metabolism and Health Science 2020;3(2):31–34. doi:10.18231/j.ijnmhs.2020.007 · Full paper (PDF)
Science says.Your spoon decides.
Seven flavors, one Professor, all Digestibility Corrected†.
†Nutritional Facts are Digestibility Corrected. Digestibility Corrected is an FDA term used to represent a correction in calorific yields from a food or macronutrient. Digestibility may vary on an individual basis.
*Comparison values for typical peanut butter are from USDA FoodData Central, rounded, for general reference only. Professor Nutz™ is a trademark of Professor Nutz LLC.