The appetite is controlled by the following hormones: insulin, ghrelin, leptin and neuropeptide Y.
Ghrelin is the hormone that increases the appetite, while leptin decreases it and the amount of energy needed by the cells is taken from sugar or glucose with the help of insulin hormone. Both insulin and leptin are released during a high-carbohydrate meal, furthermore, leptin has a great influence on the total quantity of thyroid hormone released and effective conversion from inactive T4 into active T3. The leptin resistance leads to a lack of accuracy of reception of fullness signals and to an increase in appetite.
The proper levels of these hormones can be controlled by having adequate protein-rich breakfasts and meals. These levels can also be controlled if stress and lack of sleep are avoided.