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NutrInsight • About the value of controlling appetite
3 FACTORS INFLUENCING
THE REGULATION OF APPETITE
The physico-chemical characteristics of foods, such as their protein and fibre content, or viscosity, constitute possible tools that could be exploited by products intended to help people to manage appetite better. Nevertheless, at the same time many other parameters (anxiety, social habits) interfere with the physiological signals involved in regulating hunger.
3.1
The effect of nutritional composition on food intake
The composition of foods in terms of macronutrients has a major impact on the regulation of eating. The distribution of macronutrients has effects at two levels: by influencing the energy density of food – a food that contains a high level of lipids will provide more calories than one with a high fibre content; but also via the direct role of macronutrients on satiety and on satiation, while it is being assimilated.
The impact of proteins, carbohydrates and lipids on satiety and satiation in human subjects has been demonstrated by clinical trials comparing the effect of meals with different contents of these three basic nutrients, which were identical in taste and appearance (62;63). In addition, animal studies involving the direct infusion of specific nutrients into the digestive tract have made it possible to assess their effects under more extreme conditions (63).
The satiating potential of proteins
It is now thought that proteins have a greater satiating potential than carbohydrates and lipids (and than alcohol), for the same calorie content and for the same energy density (64). Furthermore, they have the advantage of contributing little to the energy density of foods as a result of their
moderate calorie content (4 kcal/g).
Thus, out of fourteen short-term studies, eleven demonstrated that enriching
a meal with proteins (with at least 40% of energy obtained from proteins) to the detriment of another macronutrient, increases the sensations of satiety over several hours. In addition, 8 out of 15 studies showed that after a meal containing at least 50% protein, the subjects consumed less energy at
the next meal (65).
In the long term, high protein diets lead to a reduction in food intake.
However, the evidence is less conclusive, because the levels of protein enrichment were lower than in the short-term studies (between 23 and 45% of the energy provided by proteins) (65). High-protein diets seem to have a more marked effect on satiety when the subjects could eat ad libitum
throughout the follow-up period (66).
The reduction of food intake as a result of high-protein diets is not necessarily associated with a reduction in body mass or a loss of fat mass. Out of ten studies identified, although most revealed a greater loss of fat mass, only three demonstrated a significant reduction of fat mass relative to a diet containing normal protein levels (65). The satiating potential of proteins was due to their ability to induce, on the one hand, an increase in osmolarity, resulting in the distension of the stomach and the stimulation of gastric mechanoreceptors (63). And, on the other hand, to induce the secretion of hormones involved in satiation and satiety such as CCK, GLP-1 and insulin.
[ Proteins have
a greater satiating potential than carbohydrates or lipids. ]
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