Question

Describe the logic and methodology of “preloading" studies, as a strategy for determining factors that influence satiety, the reduced willingness to eat (lower “hunger” or “appetite”) following a meal. Use an example from research (either human or animal) to illustrate how this method has demonstrated the impact of a specific food characteristic (e.g. the food’s color, or taste, or macronutrient composition) on satiety. Additionally, can preloading studies be used to investigate the impact of non-biological (e.g. social or psychological) influences on satiety? If yes, describe a hypothetical study to test the impact of such an influence. If not, explain why.  

Answer 1

Answer.

In the context of the rising prevalence of obesity around the world, it is vital to understand how bodyweight and the ability to balance energy intake is critical to survival. To the end, there has been an increasing focus on discovering the bodily mechanisms which are involved in the natural control of appetite. Satiation and satiety are part of the body’s appetite control system that cause one to stop eating by creating afeeling of fullness that persists after eating, and they thus suppress further consumption.
Satiation and satiety are controlled by a number of factors that begin when a food or drink is consumed and is metabolised in the gastrointestinal tract. Signals about the ingestion of energy are integrated by the brain, and this is how satiation is stimulated.

A substantial bulk of research has been conducted to investigate the effect of different foods, drinks, and macronutrients on satiety. By and large, the energy density of a food or drink appears to have the most impact on satiety. This points to the amount of energy that a food provides per unit weight (kJ/g, kcal/g). When energy density is controlled, the macronutrient composition of foods does not appear to have a major impact on satiety. A common study design that can be used in measuring satiation or satiety over a short period involves the use of a test preload in which the different food components or variables of interest are carefully controlled. This is followed by ratings given by subjects about sensations of fullness or hunger, at intervals and then, after a predetermined time interval, a test meal at which energy intake is measured. In general, high-fat foods tend to have a higher energy density than high-protein or high-carbohydrate foods, and foods with the highest water content tend to have the lowest energy density. Some studies have shown that energy from protein is more satiating than energy from carbohydrate or fat. In addition, certain types of fibre have been shown to enhance satiation and satiety.

However, besides these internal signals, certain social and psychological factors may influence appetite and energy intake, for example, physical factors such as bodyweight, age or gender, or emotional mood states such anxiety, sadness, etc, may trigger hunger for ‘ comfort foods’ or foods which are exceptionally high on fat and carbohydrates( sugar). This knowledge can be Practically applied as a strategy to improve the satiating efficiency of foods designed for appetite control, by incorporating components which are high in satiating efficiency per unit of energy within the diet of the affected individuals.