Why we feel hunger-How hunger created in our body

What is hunger?

Hunger is a strong craving for something to eat and caused by the deficit of food in the body. Eating is a more complex process in our body. There are lots of different things to eat. We need to eat a number of different kinds of things (proteins, carbohydrates, fat, and minerals) to be healthy. We need to select the proper balance of foods that contain these things. 

Evolution has given our brains ways of helping us select the foods we need and avoid eating things that might poison us. Some of these ways involve the basic taste preferences we were born with. Others involve mechanisms for learning preferences for particular foods and aversions to others.

What is most important when selecting food?

Flavour is the most important factor in food preferences. The flavor contains both taste and odor components, but the taste has been relatively more important in human evolution. Humans, like other mammals, are born ‘programmed’ with likes and dislikes for particular tastes.

Even infants respond to sweet tastes with lip-smacking movements and facial expressions indicative of pleasure. They respond to bitter tastes by turning away and pulling their faces into expressions of disgust. Food manufacturers capitalize on our natural ‘sweet tooth’ to devise sweet foods that spur many people to overeat.

How the body uses food for energy?

We eat to maintain energy homeostasis in the body. Body cells burn fuel to produce the energy required for the tasks they perform. Physical exercise causes muscle cells to burn extra fuel to meet the metabolic needs placed on them by energetic movement.

By burning more fuel, they draw on stores of calories that have been deposited as body fat or other forms of ‘stored energy. Even when reading the neurons of the brain are burning fuel to meet the metabolic needs created as they fire electrical impulses and make and release neurotransmitters.

The main fuel used by these brain neurons is glucose, a simple sugar. Without fuel, neurons cannot work. In fact, our brain uses more glucose when you ‘exercise it’ by thinking hard such as when you make a difficult decision.

Glucose is present in many fruits and other foods. It can also be manufactured by the liver out of other sugars or carbohydrates. Once you’ve eaten a meal, a great deal of glucose will be absorbed into the bloodstream through the process of digestion. 

Even more, will be created by the liver as it converts other forms of nutrients. In this way, a meal replenishes the fuel needed by brain neurons and your body’s other cells. Because our cells need fuel, we might expect hunger to be solely a homeostatic motivation controlled entirely by the need to keep sufficient sources of energy available in the body. 

How Hunger is developing in the body?

When we are hungry our stomach sometimes growls. At such moments, the stomach wall engaged in muscular contractions, creating the burbling movements of its contents. Pressure sensors in the stomach detect emptiness and trigger both contractions and the psychological experience of hunger.

But stomach sensations from contractions are not the real cause of hunger. In fact, people who have had their stomachs surgically removed for medical reasons, so that food passes directly to the intestines, can still have strong feelings of hunger.

The stomach does have receptors that are important to changes in hunger. The receptor is activated by sugars and other nutrients in stomach contents and sends a neural signal to the brain.

The physiological signal for hunger is more directly related to the real source of calories for neurons.

The brain itself is its own calories. Neurons in the brain use glucose as their principal source of energy. Neurons in the brain are sensitive to glucose levels. When the level falls too low, the activity of these neurons is disrupted and the brain, producing a hunger signal.

Such hunger can be produced artificially in laboratory animals even just after a meal. If chemicals that prevent neurons from burning glucose as a fuel are infused into an animal’s brain, the animal will suddenly seek out food. 

The brain has been fooled into sensing a lack of glucose, even though glucose was actually present because the neurons have been disrupted in the same way as they are when glucose is low. Bain rely on nutrient signals from the liver because the liver can more accurately measure the various types of nutrients used by the body. 

The brain detects chiefly glucose, but other forms of nutrients, such as complex carbohydrates, proteins can be measured, stored, and sometimes converted into other its role as a general currency exchange for various nutrients may stores available to the body.  

How we motivated to eat?

Signals for hunger are processed by the brain in two stages to produce the motivation to eat. First, signals from hunger receptors in the brain itself and satiety signals relayed from the stomach and liver are added together in the brain to detect the overall level of need.


This integrated hunger assessment is connected in the brain stem to the sensory neural systems that process taste. Tastes neurons in the brain responsive during hunger that why food tastes more palatable when we are hungry.

Hunger signals of the brain are processed in the forebrain (front part of the brain) which is the executive part of the brain. The forebrain executes the command and we motivated to eat food or try to obtain food.

Why do we find sweet foods and drinks so attractive? 

In ancient times our ancestors heavily rely on sugar because of its caloric value and rare in quantity. Evolutionary psychologists have suggested that it is because the sweetness is an excellent ‘label’ that told our ancestors, that particular food or berry was rich in sugar, a class of digestible carbohydrates.

Eating sweet foods is an excellent way to calories, and calories were not abundant in our evolutionary past. Experience with other forms of taste consequence pairings may also be the basis for developing preferences for tastes that are initially not pleasant, such as alcohol or coffee.

In other words, the physical effects of alcohol or caffeinated coffee may cause us to develop preferences for these foods, even if we initially do not like their taste. The same kind of process can work in the opposite direction to produce a strong dislike for a particular food. 

If our first sample of tasty food or drink is followed sometime later by nausea or vomiting, we may find that the food is not tasty when next time tries it. We remember the feeling of last time.  Hunger is a strong craving for something to eat and caused by the deficit of food in the body. Eating is a more complex process in our body. 

There are lots of different things to eat. We need to eat a number of different kinds of things (proteins, carbohydrates, fat, and minerals) to be healthy. We need to select the proper balance of foods that contain these things.

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