What is the harm of fat-free diets?

Low-fat diets – one of the key mistakes in mass nutrition science at the end of the 20th century.

Starting from the 1970s, the medical community actively promoted low-fat diets aimed at reducing cholesterol and, consequently, the risk of atherosclerosis and heart attacks. However, this strategy yielded unexpected and largely opposite results.

Why fats are important for heart health

Fats are the building blocks for cell membranes. Every cell in the body, including heart and blood vessel cells, is surrounded by a membrane made of phospholipids and cholesterol. Cholesterol makes the membrane flexible and resistant to oxidative stress. A deficiency leads to vessel fragility and inflammatory reactions.

Fat-soluble vitamins A, D, E, K are not absorbed without fats. Vitamin K2 is necessary for activating proteins that regulate calcium deposition — it should not enter the vessel walls (atherosclerosis) but should be directed to the bones. 

Vitamin E — a powerful antioxidant that protects lipids in LDL from oxidation (the main trigger of atherosclerosis).

Polyunsaturated fatty acids Omega-3 (EPA, DHA) have pronounced anti-inflammatory effects, reduce blood viscosity, and prevent thrombosis. A deficiency of Omega-3 in low-fat diets sharply increases the risk of heart attacks and strokes.

What replaced fat: carbohydrates and trans fats

When fats were removed from products, taste and texture deteriorated sharply. To compensate for this, manufacturers began adding refined carbohydrates (sugar, glucose syrup, starches) and artificial trans fats (margarines, hydrogenated oils).

Consequences:

Chronic inflammation. Excess sugar and omega-6 fatty acids (linoleic acid from vegetable oils) cause chronic inflammation, a key mechanism of vessel damage.

Insulin resistance and metabolic syndrome. Carbohydrate spikes raise insulin levels, and constant hyperinsulinemia contributes to fat deposition in the liver, abdomen, and also in the intimate areas of the vessels.

Increased triglyceride levels and decreased HDL (good cholesterol). These are classic markers of CVD risk that worsen with excess carbohydrates and fat deficiency.

Epidemiological data

According to retrospective studies, in the 1980s and 1990s, the consumption of low-fat products and carbohydrates in the USA and several European countries sharply increased (in accordance with dietary recommendations).

At the same time, the following increased:

• obesity;
• type 2 diabetes;
• heart diseases.