What nutrients does your body need and how do they influence the feeling of hunger and fullness? To understand how our feelings of hunger and satiety work, we first need to learn about nutrients. Proteins, carbohydrates and fats belong to the macronutrients, as they make up the largest part of our food and are the biggest suppliers of energy. Micronutrients, on the other hand, are vitamins and minerals that our metabolism needs to work. Our body needs all these important substances in sufficient quantities for the metabolism to work optimally and for less hunger to occur. If one of the indispensable (essential) substances is lacking, the body switches to hunger until enough of the missing substance has been absorbed. The optimal supply of nutrients to our body is therefore indispensable for our feeling of hunger and satiety.
Carbohydrates consist of sugar molecules. Depending on how many sugar molecules are linked together, we speak of single sugars (monosaccharides), double sugars (disaccharides) or multiple sugars (polysaccharides). A monosaccharide is a single sugar molecule such as glucose, fructose or galactose. When two monosaccharides are joined together, a disaccharide is formed, such as household sugar (sucrose) and milk sugar (lactose). The variety of carbohydrates is very large. Starch from rice or potatoes consists of very many glucose molecules and is a very long carbohydrate. During digestion, carbohydrates are separated into their individual sugar building blocks so that they can be absorbed into the blood. The longer a carbohydrate molecule is, the longer it takes for the digestive enzymes to break it down into its individual parts. This is why glucose or sucrose enter the blood very quickly. In contrast, more complex carbohydrates from starchy foods, such as rice, are broken down more slowly and energy is provided gradually. How quickly carbohydrates are broken down and the simple sugar glucose enters the blood plays a major role in the release of insulin (we will go into this later). However, there are also carbohydrates that our digestive system cannot break down, these are dietary fibres. They enter the large intestine undigested and ensure a good consistency of the stool. Some bacteria can break down the carbohydrates that are indigestible for us and feed on them, which is why dietary fibre is important for a healthy intestinal flora.
Like carbohydrates, proteins are made up of several individual components. These individual components are amino acids, which are broken down into their individual components during digestion in the same way as carbohydrates. After the breakdown, the individual amino acids are absorbed into the cells. Our body needs different amino acids in different quantities. When we consume proteins from meat, fish, eggs or protein-rich vegetables, it is therefore particularly important for our body to know which amino acids are contained in them. Protein sources are more valuable the better they meet the body's needs. Some amino acids can be converted by the body itself. Others it cannot. These are the 8 essential amino acids that we must supply to our body through food. Our body needs proteins to maintain and build muscles.
Among the fats there are unsaturated and polyunsaturated fatty acids, which have specific tasks in the body. For example, omega 3 fatty acids contribute to a healthy brain and good eyesight and can have a positive effect on blood lipid levels. Our body cannot produce these unsaturated omega-3 fatty acids itself, they have to be ingested. Unsaturated fatty acids can be compared to vitamins because our metabolism needs them to work. However, unsaturated fatty acids are quite unstable and should not be heated too much when cooking.
How can I tell where saturated and unsaturated fats are?
The more unsaturated fatty acids foods contain, the more fluid they are in the cold. Cold-water fish, for example, contain many unsaturated omega-3 fatty acids so that they remain mobile in the cold. If they had unsaturated fatty acids in their cell membranes, they would become rigid.
Vitamins and minerals
Vitamins and minerals are essential tools that enzymes need to do their job. Vitamins play a role in the utilisation of fats, carbohydrates and proteins, because they ensure that these substances are also broken down or converted correctly.
Each vitamin has a unique function at a specific point in the complex system of our metabolism. If one of these important tools is missing, what is colloquially known as "the metabolism falls asleep" happens. Work steps then no longer take place at the right speed. Some vitamins are not involved in metabolic processes, but are important for building certain body structures - bones, teeth and all our cells.
How does hunger develop and what do nutrients have to do with it?
Hunger originates in our brain, in the hypothalamus, an area of the diencephalon. Hormones and nerve pathways transmit the signals "hungry" or "full". Others signal when a nutrient is missing.
As soon as the body's reserves slowly run out, stomach cells produce, for example, the appetite-stimulating ghrelin. This is the strongest hunger hormone, but at the same time it also slows down the metabolism by causing the body temperature to drop somewhat and making you feel less like moving. Finally, the body does not know when it will get food again. After the meal, the body checks whether the stomach is really filled with the right food and whether it can set all signals to "full"; only then does the ghrelin concentration drop again. Special sensory cells in the stomach measure how much the stomach wall stretches. In the intestine, on the other hand, receptors check whether the right nutrients are arriving. Only when all this is correct can the brain finally switch to "full". A large portion of vegetables provides many vitamins and minerals and also a lot of volume, but this alone is not enough. Your meal must also contain high-quality protein sources and important fatty acids. Only then does the meal provide the right combination of volume and nutritional value and your body sets the signals to "full".
What influences the feeling of hunger and satiety?
As soon as carbohydrates are broken down into their individual parts and the simple sugar glucose enters the blood, the pancreas releases insulin. This hormone ensures that both glucose and amino acids can be brought into the cells. When these have been delivered to the cell, the insulin and blood sugar levels drop again. When the blood glucose level drops, hunger arises again. If a lot of glucose enters the blood at once, a lot of insulin is also secreted, which causes the blood sugar level to drop again very quickly and hunger arises again. If sugar is constantly supplied, we are in a constant state of ups and downs. The insulin level really goes on a roller coaster. We fall from one concentration hole into the next and rescue ourselves with a quick snack. It is not only carbohydrates that cause insulin levels to rise; proteins and amino acids also promote insulin secretion. When amino acids are ingested, however, the glucagon level rises along with the insulin level. The hormone glucagon is the counterpart of insulin when it comes to burning fat. While insulin stands in the way of fat burning, glucagon drives it. The mixture of glucagon and insulin released after ingesting a moderate amount of protein is ideal for good satiety and active fat burning. However, if too much protein is ingested and therefore a lot of amino acids enter the blood, some of the amino acids are converted into glucose. This causes the blood sugar level to rise just as if you had eaten carbohydrates. So it all depends on the right amount of protein.
Tips to support the balanced feeling of hunger and satiety
- Eat a maximum of 3 times a day (no snacks)
- Take a 4-6 hour break between meals
- Refrain from fast carbohydrates (sweets, white flour)
- Eat a portion of protein with every meal
- There should always be a large portion of vegetables on your plate.
- Add polyunsaturated fats to your vegetables after cooking (e.g. olive oil, algae oil).