A low-fat and simultaneously high-carbohydrate diet can lead to conditions close to hypoxemia (a decrease in blood oxygen levels), especially in the presence of accompanying metabolic disorders.
The main source of energy — carbohydrates
With a high-carbohydrate diet, the body shifts to a glucose-dependent type of metabolism, where the primary source of energy becomes the oxidation of glucose. This process requires active participation of insulin and depends on continuous access to carbohydrates.
However, this type of metabolism has an important physiological drawback — low efficiency in oxygen consumption:
- The oxidation of 1 molecule of glucose yields 36-38 molecules of ATP, but requires 6 molecules of oxygen (O₂).
- At the same time, 6 molecules of carbon dioxide are produced, which creates an additional burden on the respiratory system.
Lower oxygen utilization compared to fats
In comparison, during the oxidation of fatty acids:
- More energy is produced (for example, the oxidation of palmitic acid yields 129 ATP),
- Less carbon dioxide is generated per unit of oxygen, meaning fat metabolism is more economical in relation to oxygen.
Thus, with a fatty type of diet (for example, during ketosis), the body better saturates tissues with oxygen, and the lungs function more efficiently, as less CO₂ is produced that needs to be removed.
The role of fats in maintaining surfactant structure
Surfactant — is a lipid-protein film covering the inner surface of the alveoli in the lungs, which prevents their collapse during exhalation. It is almost entirely composed of phospholipids, the synthesis of which is impossible without fats in the diet.
Against the background of a low-fat diet, the synthesis of surfactant decreases, which worsens:
- gas exchange in the lungs,
- blood oxygen saturation (hypoxemia), especially under increased load (for example, during infection or physical activity).
Prolonged consumption of large amounts of carbohydrates, especially fast ones (glucose, fructose, starches), provokes insulin resistance, fatty liver, and chronic low-grade inflammation.
As a result:
- the permeability of the alveolo-capillary membrane worsens,
- the risk of pulmonary edema increases,
- breathing efficiency decreases and the likelihood of hypoxemia increases — especially during viral or bacterial loads (for example, COVID-19).
