Differential effects of dietary intake of palmitic acid and oleic acid on oxygen consumption during and after exercise

Our previous studies suggest that diets varying in palmitic acid (PA) and oleic acid (OA) content may affect energy expenditure and fat oxidation differentially. We hypothesized that, compared with a high-OA diet, a high-PA diet would lead to lower oxygen consumption during exercise and lower excess postexercise oxygen consumption (EPOC). Adults were randomized to 1 of 2 liquid diets (28 days): HI PA (fat, 40% of energy; PA, 16.8%; OA, 16.4%) (n = 10) or HI OA (fat, 40%; PA, 1.7%; OA, 31.4%) (n = 9). On day 29, the rates of oxygen consumption (V˙o2) and carbon dioxide production were measured during and for 270 minutes after 80 minutes of cycling (60% V˙o2 peak). There was no group difference (HI OA vs HI PA, mean ± SEM) in fat-free mass (53.8 ± 4.7 vs 56.9 ± 3.0 kg), V˙o2 peak (40.7 ± 2.3 vs 36.6 ± 3.2 mL/kg per minute), and work during exercise (101 ± 12 vs 101 ± 10 W). V˙o2 (L/min) during exercise (1.99 ± 0.22 vs 1.85 ± 0.19) was significantly different (P = .05) only when corrected for fat-free mass, with which it significantly correlated (r = 0.86; P < .001). During 60 to 270 minutes postexercise, the average EPOC was 9.7% ± 4.9% of preexercise V˙o2 in OA, whereas there was no EPOC present in PA (P = .06 between diets). In conclusion, a high-PA diet appears to lower V˙o2 during and after exercise compared with a high-OA diet.