Figure 3.

Relationship between protein intake and F¹³CO₂. 7 participants completed 45 metabolic trials with a range of test protein intake (0.20–2.60 g⋅kg⁻¹⋅day⁻¹). The breakpoint estimated the average protein requirement. The breakpoint was determined by using a biphasic linear regression crossover analysis. The average protein requirement and recommended protein intake were estimated to be 1.20 and 1.40 g⋅kg⁻¹⋅day⁻¹, respectively (R² = 0.64).