This study was conducted to investigate whether a higher proportion of protein or fat is more favorable for optimal ghrelin and peptide YY (PYY) release in subjects consuming low carbohydrate meals.

Eight normal weight men received, on three separate occasions, high protein low fat (HPLF) (40% protein, 25% fat), low protein high fat (LPHF) (10% protein, 55% fat) or medium protein medium fat (MPMF) (25% protein, 40% fat) meals, with equal low carbohydrates content in all three meals (35% of energy). Postprandial blood samples were collected before and 15, 30, 60, 120, 180 and 240 min following the ingestion of each meal. Plasma acylated ghrelin and PYY_3-36 as well as serum insulin, glucose and triglycerides were measured.

Comparing meals and considering each time point separately, a trend for a statistically significant difference in acylated ghrelin was observed between HPLF and LPHF meals and a statistically significant change of PYY from baseline was noted between HPLF and LPHF meals as compared to the MPMF meal at certain time points. When data were pooled together, a statistically significant difference in acylated ghrelin change from baseline was observed between HPLF and LPHF meals, while both HPLF and LPHF meals resulted in a significantly higher PYY_3-36 release in comparison to MPMF meal. AUC data analysis for PYY_3-36 revealed significantly higher values following HPLF in comparison to MPMF meal. Correlation analysis revealed a significant negative correlation between acylated ghrelin and insulin only with the HPLF meal. Postprandial glucose and triglyceride levels were not significantly different between the three meals.

In subjects consuming low carbohydrate meals, higher concentrations of proteins to fat seem to have more favorable effects on postprandial appetite hormones.