Acute effects of high-protein versus normal-protein isocaloric meals on satiety and ghrelin

PURPOSE: The objective was to compare isocaloric high-protein (HP) test meals with normal-protein (NP) test ones on satiety and ghrelin in human being. METHODS: Systematic searches were conducted by using PubMed, Cochrane library, EMBASE, and HighWire Press to identify randomized, crossover trials that investigated the acute effects of isocalorically prescribed HP versus NP test meals on satiety and ghrelin. RESULTS: Pooled analyses showed that subjects with HP test meals had a significantly higher acute satiety area under the curve (AUC) than those with NP test meals (P < 0.001). Conversely, the former had a markedly lower level of acute ghrelin at 180 min as well as acute glucose AUC, although they had a notably higher glucose at 180 min (P = 0.008). CONCLUSIONS: The meta-analysis showed that the acute consumption of HP did produce more satiety. In addition, relative to NP test meals, HP test ones may be useful in regulating postprandial glucose, whereas a significantly higher preprandial glucose combined with a lower concentration of ghrelin may contribute to the decrease in ad libitum caloric intake.