Aim: The purpose of this study was to investigate the response of postprandial acylated ghrelin to changes in macronutrient composition of meals in healthy adult males. Methods: A randomized crossover study was performed. Ten healthy adult males were recruited. All subjects received, on separate occasions, a high-carbohydrate (HC), a high-fat (HF), and a high-protein (HP) meal. Blood samples were collected before and 15, 30, 60, 120, and 180 min following the ingestion of each meal. Plasma acylated ghrelin as well as serum insulin, glucose, and triglycerides were measured. Results: The levels of acylated ghrelin fell significantly following the three meals. The HC meal induced the most significant decrease in postprandial ghrelin secretion (–15.5 ± 2.53 pg/ml) as compared with HF (–8.4 ± 2.17 pg/ml) and HP (–10.0 ± 1.79 pg/ml) meals (p < 0.05). However, at 180 min, the HP meal maintained significantly lower mean ghrelin levels (29.7 ± 3.56 pg/ml) than both HC (58.4 ± 5.75 pg/ml) and HF (45.7 ± 5.89 pg/ml) meals and lower levels than baseline (43.4 ± 5.34 pg/ml) (p <0.01). The postprandial insulin levels increased to significantly higher levels following the HC meal (+80.6 ± 11.14 µU/ml) than following both HF (37.3 ± 4.82 µU/ml) and HP (51.4 ± 6.00 µU/ml) meals (p < 0.001). However, at 180 min, the mean insulin levels were found to be significantly higher following the HP meal (56.4 ± 10.80 µU/ml) as compared with both HC (30.9 ± 4.31 µU/ml) and HF (33.7 ± 4.42 µU/ml) meals (p < 0.05). Acylated ghrelin was also found to be negatively correlated with circulating insulin levels, across all meals. Conclusions: These results indicate that the nutrient composition of meals affects the extent of suppression of postprandial ghrelin levels and that partial substitution of dietary protein for carbohydrate or fat may promote longer-term postprandial ghrelin suppression and satiety. Our results also support the possible role of insulin in meal-induced ghrelin suppression.

Lebanon is a highly urbanized Mediterranean country, characterized by its healthy traditional cuisine. With some exceptions related to sugar, sweeteners, and cereals, Lebanese food consumption is comparable with many northern Mediterranean countries. It is a collection of minimally processed vegetarian recipes, in addition to an abundance of fruits, vegetables, cereals, legumes, and nuts. Olive oil is the principle fat used, replacing other sources, in addition to many other ingredients including wild edible plants, lemon, garlic and mint.With modernization and development, consumer tastes and demands have had implications on the traditional Lebanese foods and dietary habits. Some changes occurred to the ingredients used and to the percent contribution of macronutrients to energy intake. Recent studies on food consumption patterns of the Lebanese young and adult population showed a shift in the food consumed toward increased intake of fat, milk, and animal protein and decreased intake of whole wheat bread and cereals. It seems that the Lebanese Mediterranean diet is converging with a pattern high in saturated fat, sugar, and refined foods and is low in fiber. Such a Westernized dietary pattern is associated with the increased risk of non communicable diseases such as obesity, cardiovascular disease, diabetes, and hypertension.Although the present Lebanese dietary habit has retained many of its Mediterranean characteristics, however, a duality is appearing between modernization and the strong adherence to culture and tradition.

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