While the physiological processes associated with eating, digesting and metabolising food are interesting, they can never be fully understood in humans without giving consideration to behavioural processes. Recent research suggests that in animals, a number of behavioural aspect have a significant influence on energy intake and utilisation, and in some cases are of major consideration to the study of obesity. Amongst animals humans are unique in that they creates a social occasion around eating, which varies in its nature between different cultures. The behaviour of humans when eating in a group is clearly different to the behaviour when eating alone, and this is self evident to anyone who has eaten with and without other family members or friends. Research suggests that the number of individuals present has an influence on the amount of food consumed, which may in turn influence metabolic regulation.
The influence of social eating on food consumption has been studied by the nutritional sciences. For example, one group of researchers1 used food diaries to assess the influence of social factors on eating behaviour. The subjects recorded every detail of their eating habits for a week, including the number of individuals present. The results showed, as might be expected, that more food was consumed when the meal was eaten with others. This included increases in total calories, protein, fat and carbohydrate. The subjects reported having greater satiety after consuming larger amounts of food, and also feeling less deprived in terms of hunger. When the author used regression analysis their ability to predict the size of the meal nearly doubled when they included the number of people present. This was reflected in a positive correlation between the number of individuals present at the meal and the meal size.
Therefore the presence of multiple individuals at a meal can have a significant influence on the amount of calories ingested. This may result from the fact that in such circumstances more time is spent eating and so a greater quantity of food can be ingested. In addition, special occasions, which would imply the presence of a larger number of individuals, tend to have more food present, as well as a more palatable selection, both of which may influence the amount of food eaten. The researchers also reported that the meal size was associated with the post-meal interval size, suggesting that larger food intakes result in longer time intervals between meals, presumably allowing longer time for digestion and metabolism of the ingested nutrients. However, when food was eaten in a group, this association no longer applied. Therefore social eating, a behaviour, may override a number of physiological regulators of energy intake.
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