10 facts about body fat

Fat tissue, or “saddle”, looks like a honeycomb with bubbles. These vesicles are fat cells (called adipocytes). They are present in a 14-week-old fetus. We are born with approximately 30 million adipocytes. At birth, adipose tissue accounts for approximately 13 percent. newborn’s body weight, and at the end of the first year already 1 percent. The mass of adipose tissue increases mainly by an increase in the size of fat cells, which gradually fill with triglycerides. Their source in the diet are vegetable and animal fats. Triglycerides are also produced by the liver from sugar (simple carbohydrates) and fatty acids. – As a result of a poor diet, the resulting fat cells grow excessively. In this way, we “program” overweight and obesity in adulthood, says prof. Andrzej Milewicz, endocrinologist, internist, from the Medical University in Wrocław. Adipocytes are able to accumulate a significant amount of fat in the form of triglycerides. So these are our fuel stores that the body uses when it needs extra energy due to exercise or when we have a long break between meals.

When we are adults, we have a certain, unchanging number of fat cells. There are tens of millions of them. Interestingly, when fat cells reach a critical mass of about 0,8 micograms, the programmed process of cell death begins and a new one is formed in its place. – Every eight years, up to 50 percent Fat cells are replaced, which makes it so difficult for us to lose weight. This fat is in a sense “indestructible” – says prof. Andrzej Milewicz. – When we lose weight, fat cells are drained, but a moment of weakness is enough and they will fill up with triglycerides again.

Adipose tissue accumulates: – under the skin (so-called subcutaneous fat), where it helps to maintain body temperature, – around the organs in the abdominal cavity (so-called visceral adipose tissue), where it functions isolating and shock-absorbing function, protecting internal organs against mechanical injuries.

– It is assumed that in healthy men fat may constitute from 8 to 21 percent. body weight, and in women the norm ranges from 23 to 34 percent. – says Hanna Stolińska-Fiedorowicz, dietitian from the Institute of Food and Nutrition. If a woman weighs less than 48 kilograms or is less than 22 percent adipose tissue, it may develop irregular menstrual cycles, and in extreme cases it may even stop menstruating. Adipose tissue produces hormones that affect the secretion of sex hormones. When the body lacks fats, the functioning of, among others, the functions of the ovary, testes or hypothalamus is disturbed. Fat is the most calorific ingredient in food. One gram provides as much as nine kilocalories. When the body uses fat from fat cells, free fatty acids and glycerol are released into the bloodstream. However, they are not only a reserve of energy, but also the building blocks of cells or skin epithelium. They are also the main component of cell membranes. Fatty acids are needed, among others to create cholesterol, vitamin D and numerous hormones. They are also important for many metabolic and nervous processes. Fats are also essential for cellular protein synthesis. In pathological conditions (e.g. in people with abdominal obesity) fat may accumulate in the muscles and liver. This is also the case in type 2 diabetes.

There are several types of fatty tissue in humans: White adipose tissue (WAT), accumulates under the skin or between organs. Its role is to store energy. It secretes many proteins and active hormones. White tissue fat cells in women are larger than in men and are usually concentrated in the thighs and buttocks. In men, adipose tissue accumulates mainly in the abdominal area. Brunatna- “Dobra” (brown adipose tissue – BAT). It allows you to generate large amounts of heat and maintains a constant temperature inside the body. This fat burns very quickly and provides a lot of energy. The signal to activate BAT is an outside temperature below 20-22 ° C. In cold weather, the volume of blood flowing through brown tissue can increase up to 100 times. We have the highest amount of brown adipose tissue right after birth. It is located between the shoulder blades, along the spine, around the neck and around the kidneys. The amount of brown adipose tissue decreases with age and with increasing body weight (obese have less of it). It’s a pity, because it is believed that this tissue in adults can prevent obesity and insulin resistance. Brown adipose tissue is highly vascular and innervated. It is actually brown in color due to the accumulation of a large number of mitochondria in it. Adult brown fat is present in trace amounts, mainly around the nape of the neck and between the shoulder blades, but also along the spinal cord, in the mediastinum (near the aorta) and around the heart (at the apex of the heart). Beige – considered an intermediate form between the cells of white and brown tissue. Pink – occurs in pregnant women and during breastfeeding. Its role is to participate in the production of milk.

The body stores energy mainly in fat cells (approx. 84%) and in muscles and the liver in the form of glycogen (approx. 1%). The latter supplies are used up after several hours of strict fasting between meals, which is why they are mainly used to maintain an optimal blood glucose level. If we eat too much sugar, its excess is converted into fatty compounds thanks to insulin. Fats synthesized from glucose in the liver are transferred through the blood to fat cells, where they are stored. Also, excess dietary fats eventually lead to their storage as triglycerides in adipose tissue. In short, fat begins to accumulate when we consume more calories than our body can use. Their excess is stored in the adipose tissue. Each of us needs a different amount of calories per day. It is known that the basic metabolism in healthy and properly nourished people accounts for 45 to 75 percent. total energy expenditure. This is the amount of energy the body “burns” for digestion, breathing, heart function, maintaining the correct temperature, etc. The rest of the combustion is spent on daily activity: work, movement, etc. Ok. 15 percent The calorie pool contains protein from which muscles and other body tissues are made. However, the body protects proteins and amino acids from being used up for energy purposes. He uses them when he has no other source of energy, e.g. during extreme fasts. Then “the body eats itself”, usually starting with the muscles.

During intensive weight loss, longer fasts, or due to a significant lack of calories in the diet, which is accompanied by high physical effort – then the fats stored in fat cells are released into the blood. The signal for their release (in a process called lipolysis) is low blood glucose levels.

White adipose tissue produces many hormones. They include, among others hormones that affect insulin secretion and action, such as adipokines, apelin, and visfatin. Hunger is a factor that inhibits apelin secretion, and apelin levels increase, as does insulin levels, after a meal. It also produces a lectin that crosses the blood-brain barrier and reaches the central nervous system. It is called the satiety hormone. Leptin secretion is highest between 22 p.m. and 3 a.m., which is sometimes explained as the effect of stopping food intake during sleep.

In adipose tissue there are cytokines, proteins that are characteristic of inflammation. Indicators of inflammation in it are largely derived from connective tissue cells and macrophages (“soldiers” who are to cleanse it of bacteria, viruses, excess cholesterol or fragments of damaged cells), which are represented in large numbers there. It is believed that inflammatory cytokines and adipose tissue hormones modifying the effects of insulin play an important role in the development of vascular complications in the course of metabolic syndrome and type 2 diabetes.

Scientific research shows that cannabinoids are also produced by adipose tissue, which may explain why people who are obese, and therefore have more of it, are often naturally more cheerful than others. Recall that cannabinoids are naturally occurring ingredients, including in cannabis. In most cases, they bring a person into a state of slight euphoria. But few people know that these substances are also produced by the human body.