Evidence for a protein leverage effect on food intake in a Norwegian population.
Level 4 - case-series / case-control
Cross-sectional population-based study
PubMed 42102975 · doi:10.1016/j.appet.2026.108581
What was done
This pre-registered cross-sectional study examined the protein leverage hypothesis using data from 11,152 participants aged 40–99 years in the seventh survey of the Tromsø Study (2015–2016) in Norway. Regression analyses evaluated associations between habitual dietary protein intake, total energy intake, BMI, and ultra-processed food (UPF) proportion.
What was found
Total energy intake was negatively associated with dietary protein proportion (L = -0.36, p < .001) and positively associated with dietary fat (L = 0.33, p < .001). Total energy intake showed no positive association with BMI, precluding testing of protein leverage on BMI. Proportion of UPFs was positively associated with total energy intake (b = 554, p < .001), negatively associated with dietary protein proportion (b = -2.0, p < .001), and positively associated with BMI (b = 0.011, p = .026).
Why it matters
This paper provides population-level evidence consistent with the protein leverage hypothesis, indicating that lower protein density and higher UPF intake correlate with increased total caloric consumption.
Limits
The cross-sectional design cannot establish causality. Dietary data rely on self-report, which is susceptible to misreporting. The lack of an association between total energy intake and BMI prevented assessment of protein leverage effects on body weight, and findings from middle-to-older aged Norwegians may not generalize to other populations.
Cited by
- supports The protein leverage hypothesis posits that the human body maintains appetite and drives food-seeking behavior until an adequate target intake of dietary protein is achieved.