In biological systems, most metabolic pathways are interconnected. The cellular respiration processes that convert glucose to ATP—such as glycolysis, pyruvate oxidation, and the citric acid cycle—tie into those that break down other organic compounds. As a result, various foods—from apples to cheese to guacamole—end up as ATP. In addition to carbohydrates, food also contains proteins and lipids—such as cholesterol and fats. All of these organic compounds are used...

How animals obtain and eat their food is called foraging behavior. Foraging can include searching for plants and hunting for prey and depends on the species and environment.

The human body gets energy from the three macronutrients: carbohydrates, proteins, and fats. Energy is released when the chemical bonds in the organic compounds present in the food are broken down. The energy content of food is measured in kilocalories (kcal), defined as the amount of heat required to raise the temperature of one kilogram of water by one degree Celsius. This value is determined by measuring the temperature change of the water surrounding a calorimeter after the complete...

Binge eating disorder is a significant mental health condition characterized by recurrent episodes of excessive food consumption within a short period, accompanied by a perceived loss of control over eating behavior. Unlike occasional overeating, binge eating disorder is marked by distressing emotions such as guilt, shame, and anxiety following binge episodes. The disorder affects individuals across different ages and backgrounds, with profound implications for physical and psychological...

Short-term regulation of food intake primarily involves neural signals from the gastrointestinal (GI) tract, blood nutrient levels, and GI tract hormones. Communication between the gut and brain via vagal nerve fibers plays a significant role in evaluating the contents of the gut. Clinical studies have shown that protein ingestion produces a more prolonged response in these nerve fibers compared to an equivalent amount of glucose. Additionally, the activation of stretch receptors caused by GI...

During the initial hours of fasting, the body uses up its glycogen stores as an energy source. Once these glycogen reserves are depleted, the body begins breaking down stored triglycerides and structural proteins. During this stage, glycerol becomes a key substrate for gluconeogenesis, while free fatty acids undergo beta-oxidation to provide energy for tissues, such as skeletal muscle. In the fasting state, the body spares protein breakdown as much as possible to conserve muscle and structural...