Fats

The small intestinal bacterial overgrowth syndrome (SIBO) is directly related to the dysfunction of the small intestine: normally, there are very few bacteria in it, but with SIBO, they actively multiply.

The body has natural defense mechanisms against such overpopulation, and one of the most important factors is bile.

When a person eats fatty food, bile is released from the gallbladder into the duodenum. This triggers several important processes.

Bactericidal action of bile. Bile contains bile acids and salts that damage bacterial membranes, disrupt their osmotic balance, and effectively act as a natural antiseptic. This is especially important for the small intestine—this is where sterility is maintained and the growth of microbes is limited.

Maintaining normal intestinal motility. Bile acids stimulate peristalsis. Good motility prevents food from stagnating, which means that bacteria do not get the conditions for excessive multiplication.

In SIBO, stagnation and slow movement of chyme are often observed—bile helps to break this vicious cycle.

Emulsification of fats and nourishment of the mucosa. Bile breaks down fats into small droplets, facilitating their absorption. Fatty acids, in turn, nourish the mucous membrane and promote the restoration of the intestinal barrier. The stronger the mucosa, the less likely bacteria are to attach and start to proliferate.

Regulation of microbiota through bile acids. Some bile acids in the intestine are transformed by bacteria into secondary acids. These compounds act as signaling molecules, regulating the composition of the microbiota and reducing the excessive growth of conditionally pathogenic species.

If the diet is low in fat, the gallbladder empties infrequently, bile stagnates, and its bactericidal function weakens. This creates ideal conditions for the development of SIBO.

Therefore, regularly including healthy fats (butter and coconut oil, lard, fatty fish, egg yolks, meat with natural fat content) supports the natural defense of the small intestine against bacterial overpopulation.

This logic is fully supported by the physiology of children's growth, energy metabolism, and hormonal regulation.

Fats — fuel for growth

The child's body is growing rapidly: cells are actively dividing, the brain is forming, and the immune, hormonal, and nervous systems are developing. All of this requires not only building materials but also high-density energy, which fats provide much more than carbohydrates:

• 1 g of fat provides 9 kcal, compared to 4 kcal from carbohydrates.
• Fats are involved in the formation of cell membranes, especially in the brain.
• Omega-3 and omega-6 fatty acids are essential for the myelination of neurons, vision, and hormonal balance.

If a child does not get enough fats, the body operates on a starvation diet, which manifests as:

• slowed linear growth,
• problems with concentration and learning,
• increased susceptibility to infections (due to weak immune protection),
• emotional instability and anxiety.

Temporary rounding — a physiological norm

Before each growth spurt, a child may slightly round out. This is not obesity, but an energy investment by the body. Under the influence of growth hormone, this fat is then converted into length, into the growth of the skeleton and organs. Such phases occur before the ages of 3–4, at 6–7 years, and during puberty.

The fear of fat among parents (for example, "fat-free" diets or low-fat products for children) can disrupt this natural cycle.

Insulin resistance disrupts the growth system

When a child's diet is based on frequent carbohydrate snacks, sweet cereals, juices, and pastries, a chronically high level of insulin develops, followed by insulin resistance.

In this case:

• Insulin suppresses growth hormone.
• Lipolysis (fat breakdown) does not start → the body cannot use stored fats.
• Instead of growing taller — fat tissue accumulates, especially in the abdominal area.
• Growth slows down, muscle mass does not increase, and children become lethargic, tired, and anxious.

What parents should consider

• Do not restrict fats in the diet of a healthy child (especially animal and saturated fats: eggs, butter, fatty meat, liver, fish, breast milk).
• Avoid frequent sweet snacks and juices — they maintain high insulin levels.
• Pay attention to growth periods and "rounding" — they are physiological if the diet is balanced.
• Watch for signs of insulin resistance: abdominal obesity, fatigue, poor sleep, hyperactivity, cravings for sweets, growth delay.

The ratio of proteins and fats 1:2 in a low-carbohydrate diet. When a person follows a low-carbohydrate diet (for example, keto), the main source of energy shifts from glucose to fatty acids and ketone bodies. In this state:

• Carbohydrates are virtually absent, insulin levels decrease;
• The body actively breaks down fats (lipolysis) for energy;
• The liver produces ketones from fats, which replace glucose for the brain, muscles, and other tissues.

In such conditions, fats become fuel, while proteins serve as building material and a backup energy substance (through gluconeogenesis). A ratio of 1:2 (proteins:fats) is considered physiologically justified:

• Excess proteins will be converted into glucose, which will interfere with ketosis;
• Fats should be more abundant to ensure sufficient ATP levels, especially from saturated fatty acids;
• At the same time, protein intake should not be less than normal to prevent the breakdown of one's own muscles and immune proteins.

Why such a ratio leads to atherosclerosis and obesity on a high-carbohydrate diet. When the diet is high in carbohydrates, with simultaneous high intake of fats (especially saturated), metabolism reacts quite differently:

1. Insulin is high – carbohydrates raise blood glucose levels, to which the body responds by releasing insulin. Insulin: blocks fat breakdown (inhibits lipolysis), promotes fat synthesis (lipogenesis), stimulates fat accumulation in tissues.
2. Fat is not burned – it accumulates, as the body prefers to burn glucose first.
3. Atherogenic lipoproteins are formed – especially in conditions of excess glucose and insulin. VLDL (very low-density lipoproteins) and LDL (low-density lipoproteins) are synthesized more actively. These particles are more easily oxidized and damage the endothelial cells of blood vessels. The formation of atherosclerotic plaques begins.
4. Obesity – especially visceral, increases, as fat is easily deposited with an excess of energy coming from carbohydrates and fats simultaneously.

Biochemical essence. In a low-carbohydrate diet: fats = fuel, proteins = structure + a little glucose (through gluconeogenesis). In a high-carbohydrate diet: glucose = main fuel, while fats are "excess," if not burned, they accumulate.

Therefore, the ratio of proteins and fats should be adapted to the proportion of carbohydrates in the diet.

• A low-carbohydrate diet requires more fats, fewer proteins (within normal limits), and almost zero carbohydrates.
• A high-carbohydrate diet requires limiting fats (especially saturated) to avoid metabolic conflict and fat accumulation.