The Study
Diets high in protein or saturated fat do not affect insulin sensitivity or plasma concentrations of lipids and lipoproteins in overweight and obese adults.
This study is like a fair science experiment where people were randomly given different diets to see what happens. It can tell us that, for this group of people over a month, eating more protein or saturated fat from dairy didn’t make their bodies worse at using insulin.
Analysis score
Maximum 90 for a randomized controlled trial.
Where the score came from
Scientists wanted to see if eating more protein or saturated fat from dairy affects how your body handles sugar and fat. They gave people different diets for 4 weeks and checked their blood.
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 572 / 100
Quality score
Participants are randomly assigned to treatment or control groups, minimizing bias. The gold standard for testing whether an intervention causes an effect.
Key takeaways
Summary
Based on the study abstract and findings.
- 1The blood sugar increase is small and may not matter much for healthy people, but could be relevant for those at risk of diabetes.
- 2The lack of harm from higher dairy fat or protein is reassuring over short periods.
- 3People eating more protein with less fat had slightly higher blood sugar (0.47 mmol/L more).
- 4More protein or fat didn’t change insulin sensitivity or cholesterol.
- 5When BCAA levels went up, the body cleared insulin slower and released more insulin quickly.
Score breakdown, methodology, conflicts of interest, evidence analysis & raw study data
Publication
Journal
The Journal of nutrition
Year
2014
Authors
S. Chiu, Paul T. Williams, Taylor Dawson, R. Bergman, D. Stefanovski, S. Watkins, R. Krauss
Related Content
Claims (6)
If you're overweight and eat a lot of protein—especially from whey—for a month, your blood sugar might go up a bit, but only if you're also eating very little saturated fat. If you eat more saturated fat, that same high-protein diet doesn't seem to affect your blood sugar.
If you're overweight, eating more saturated fat from dairy — like cheese or butter — for a month probably won't hurt your blood sugar control or cholesterol levels compared to eating less of it.
If you're overweight or obese and eat the same number of calories, boosting protein or saturated fat from dairy for a month doesn't seem to hurt your blood sugar control or cholesterol levels.
In people who are overweight or obese, higher levels of certain amino acids in the blood during diet changes are linked to the body clearing insulin more slowly and releasing more insulin when blood sugar rises — which might mean these amino acids affect insulin in ways not related to how sensitive the body is to it.
If you're overweight, eating a lot more protein — especially from whey — for a month won't help your body use insulin better unless you're also losing weight.
Eating a lot of saturated fat might make your body less responsive to insulin and cause fat to build up in your liver. If you also eat a lot of protein, it could push your body to make more sugar, which might raise your blood sugar—especially if you're prone to it.
Not medical advice. For informational purposes only. Always consult a qualified healthcare professional before making health decisions.