Lack of satiety: what happens in the body?

The interaction of hunger and satiety occurs in our body several times a day. The control center is located in our brain: in the hypothalamus. Here are the signals that the body sends when you feel hungry or full. But not only exercise determines appetite. External stimuli, such as a particular smell, the appearance of food, or a particular taste, also affect our feeling of hunger. Physiological and emotional (hedonic) signals condition each other and are closely interconnected.

How does the feeling of satiety come about?

Hunger is the body's warning signal. Organs, especially the brain, need energy to function optimally. That is why hunger eventually turns into an irresistible craving. Consequences may include restlessness and aggressiveness. That is why we try to satisfy our hunger as quickly as possible.

Once in the stomach, food stretches the wall of the stomach. This is sent to the brain by so-called mechanoreceptors. But distension of the stomach in itself does not cause a feeling of satiety. In addition, so-called chemoreceptors in the intestines and liver determine how much nutrients have been absorbed. In this case, the secretion of various hormones that are important for the energy balance of the body occurs, the pancreas causes an increase in blood sugar levels. Microorganisms from the gut also send signals. Only when the mechano- and chemoreceptors react and the hypothalamus receives a message about the correct level of hormones do we begin to feel full. That's when the body releases the happy hormone serotonin, among other things, signaling: "I'm full, I'm satisfied."

According to research, it takes between 300 and 400 cubic centimeters to fill the organ with a volume of 300 to 400 cubic centimeters—about a small to medium serving of pasta—to properly stretch the stomach. Liquids can also stretch the stomach, but they usually pass quickly into the intestines.

Hungry or full? Different hormones involved

According to science, there are many hormones that affect feelings of hunger and satiety. However, many interactions have not yet been studied. Overview of the main satiety hormones:

Leptin constantly gives the body feedback on energy status. The hormone is associated with body fat. When leptin levels drop, we feel hungry. When we eat food, its level rises again, and the hormone contributes to the feeling of satiety.

Ghrelin is a leptin antagonist and is also called the "hunger hormone". When the stomach is empty and the body needs energy, ghrelin levels rise. If eaten, its value will drop again.

When fatty acids and amino acids are absorbed through the intestines, cholecystokinin is produced. This hormone is also responsible for feeling full.

The digestive hormone GLP-1 also has a satiating effect, it is released during the absorption of glucose and fatty acids.

Also, due to the increase in glucose levels, the hormones amylin and insulin are produced, which also contribute to the feeling of satiety.

How long does it take to get full?

Only after about 20 minutes does a conscious feeling of satiety usually occur. In this case, various factors of nutritional composition play a role:

Satiety depends on hormones, which are also released to varying degrees with different food composition. This applies, for example, to sweet foods such as chocolate: they contain a high dose of glucose, from which the body quickly obtains energy. So, sweet signals the body about a short-term burst of energy. But, unfortunately, it is also very high in calories and, as a rule, contains little to no fiber and other valuable nutrients. Sweets also cause blood sugar levels to rise very quickly and fall again after insulin is released, and low blood sugar causes hunger.

But psychological aspects also play a role in the feeling of satiety. Eating at a particularly good restaurant or hanging out with people you know affects our feelings of hunger and satiety.

Lack of satiety - what are the reasons?

Our body is programmed to want available food immediately. However, in times when food and snacks are constantly within reach, this becomes a problem. In addition, we often eat to reward ourselves, to relax, or to cope with stress. Overview of reasons:

Chronic stress and lack of sleep increase cortisol levels, the reward system in the brain drives an appetite for sweets and fats. Result: Patients reach for chips or chocolate to relax. Emotions drive our behavior, and the perception of physical sensations of satiety fades into the background, we no longer perceive them so well. In addition, a chronically stressed brain consumes less energy, gets less from food, and leaves more to the body. Thus, fat deposits grow because food is less digestible.

The lack of a natural feeling of fullness can also have psychological causes, such as those caused by trauma. This can occur with obesity, as well as with anorexia (anorexia) or bulimia (addiction to overeating).

Taste can also be associated with emotions. Sweets are often invented in childhood as a treat. Babies are also very sensitive to sweet tastes, which can be associated with nurturing and emotional warmth, and if we feel the need, we reach for something that tastes like inner warmth - chocolate, for example. Because the energy density is high, we can also eat a lot of it without triggering the satiation system.

Fast food: French fries or hamburgers have a high energy density in a relatively small amount. The stomach needs more because it is not yet sufficiently stretched. Then the food is eaten quickly, so that the feeling of satiety cannot arise.

The hormone leptin and body fat cells are directly related to each other. The more fat cells in the body, the higher the level of leptin. Thus, when overweight, so-called leptin resistance can develop. That is, the feeling of satiety is no longer present in those who suffer from this disease. Belly fat, in particular, plays an important role here.

Diet can also disrupt the feeling of satiety: if you suddenly reduce your calorie intake dramatically, the body will respond with hunger. The reason is the strong production of the hormone ghrelin. If the diet is canceled now, irritation will occur in the body, as with continuing the diet and then switching to a normal diet.

Medications such as antidepressants, antiepileptic drugs, and antipsychotics that directly affect brain metabolism can cause a lack of satiety. Diabetes medications, blood pressure medications, and cortisone can also have this effect.

Food cravings often occur when blood sugar drops rapidly and dramatically. Thus, eating a meal with a lot of sugar or simple carbohydrates can cause the feeling of satiety to not last long.

Eat slowly and take breaks

Mindful eating is an important step towards healthy eating and, as a result, to a feeling of satiety. It is important to eat mindfully. Already in the mouth, we can consciously influence satiety. Conscious and prolonged chewing of food contributes to better satiety. In addition, due to their high nutritional value, unprocessed and natural foods keep you feeling full longer than fast food or processed foods. The consistency of food also plays an important role: food that is resistant to bites keeps you feeling full longer than soup without a side dish.