With the epidemic of obesity growing exponentially in our country, not only has there been a sharp decline in physical activity, but our eating behaviours have also changed drastically.
With availability of food 24X7, a new café or restaurant opening nearly every week, millions being spent on food, an average consumer is seduced by the advertisements and that reflects in our eating habits.

Hunger, an urge to eat, is followed by an unpleasant sensation of hunger. Appeasing the urge creates satiety, after which no desire to eat exists. In contrast, appetite—a complex phenomenon, refers to signals that guide dietary selection, often in the absence of obvious hunger. Appetite comes mostly from a psychological state but can also have a physiological dimension, such as the desire for salty or sweet foods. Further, these forces mainly are “positive” signals.

Internal or physiological forces include neurotransmitter production, circulating hormones, state of health, medications, nutrient receptors in small intestines and degree of physical activity.
Social influences like religion, philosophy, cultural taboos, presence of others, taste and palatability, anxiety, stress, psychological disturbances, environmental factors such as climate and metabolic factors (hormone levels, caloric requirements), aromas, meal time, memories, and certain food advertisements are the external factors that influence our eating habits and patterns.

Hunger is mostly regulated by internal cues to eating, while it is largely the external influences that govern appetite. The physiologic basis of appetite and hunger is not completely understood but it is clear that both internal and external cues regulate how we eat. The hypothalamus in the brain seems to be the operative centre and regulates hunger signals. Organs such as liver, brain, fat cells, gastro-intestinal tract, hormone-like factors (neuro-endocrine), nervous system and other aspects of body physiology influence eating behaviour. An inter-relationship between social and physiological factors is seen with mood. When depressed, some people eat, while others avoid food.
Several hormones which regulate appetite are largely influenced by genetics. Multiple chemical messengers, including as many as 25 neuro-peptides, affect food intake. Some of these are:

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