The psychology of eating is an important field of study in the 21st century, with obesity becoming one of the major health issues worldwide. Psychologists have researched the emotional and psychological aspects of eating in an effort to explain eating behavior and help people deal with weight or health issues. Problems are usually caused by psychological problems relating to food or drink and can result in eating disorders such as anorexia nervosa and bulimia.
The psychology of eating could be explained within the concepts of evolution and natural selection, according to which people, as all other animals, must eat and drink in order to survive. Every day people spend hours not only eating and preparing food but also thinking about it. However, such concepts cannot answer why people keep eating even when they do not physically need food or why people develop eating habits that harm their health and endanger their life. There is no explanation as to why certain people have more harmful eating habits than others.
According to the American Psychological Association (2011), personality traits can be associated with weight and body mass, with highly neurotic people going through cycles of gaining and losing weight throughout their lives. Examining data covering 50 years, researchers found that impulsive individuals, people who enjoy taking risks and cynical, competitive and aggressive individuals are all more likely to be overweight as they tend to give in to temptation and lack the discipline to stay healthy.
In the early 20th century, scientists developed the stomach contraction theory about hunger, according to which hunger was caused by contractions of the stomach. Later studies showed that stomach contractions are not necessary prerequisites for hunger. Researchers have proved that certain sensations can affect hunger. For example, cooking noises and the smell of food can make a person feel hungry. People can feel a sudden crave for a piece of cake just because they have seen an image of it in a commercial or a picture. Such a process is similar to what happened to the dogs in the famous experiment of Russian physiologist Ivan Pavlov. Pavlov demonstrated that dogs started to salivate at the sight or noise associated with food.
A study into the eating habits of Muslim men and women during the holy month of Ramadan, when believers fast from sunrise to sunset, has shown that women feel much more hungry than men at the beginning. The explanation given by researchers is that while men are away working, women are at home preparing food for the children, who eat during the day, and for the rest of the adults, who eat during the night. Because women are constantly dealing with food, this affects their appetite and makes them more hungry.
The air temperature is another external factor that can influence eating. According to the temperature theory of hunger, animals and people eat more in cooler environment rather than in hot environment. Other psychologists argue that hunger plays a minor role in people's decision whether to eat or not. Some of the psychological reasons for such eating behavior can be traced back to childhood. Parents often teach their children that they should eat everything on their plates, regardless of whether they are hungry or not.
Reward is another psychological aspect of eating which orginates from childhood experiences. Parents often reward their children with candies or ice cream for "being good" or for some achievement. As adults, people tend to keep this eating behavior and reward themselves with food when they feel depressed, which helps them remember positive thoughts from their childhood. A lot of people use eating as a comfort when they are worried, nervous or when they are sad. On the other hand, people often use celebrations and family occasions such as birthdays or Thanksgiving as an excuse to eat too much.
Studies have revealed that memory and learning also play a role in people's eating behavior. The memory of a previous eating experience can determine how much and when the next meal occurs. For example, if an individual is given something which they believe is unpleasant as a child, they may dislike this food as an adult. Researchers have found that some patients suffering from memory problems might eat two meals within 10 minutes if they cannot remember when they ate last.