Nutrition Basics: Fats

The Role of Fats in the Body

Fats are an essential nutrient that serve both an energy and structural role. They act as a carrier for fat-soluble vitamins (A, D, E, and K), which cannot be properly absorbed without the presence of dietary fat.
Fat is also the most energy-dense macronutrient, providing 9 kcal per gram. Structurally, fats are involved in building cells in various tissues, and excess food energy is stored as fat deposits.
In a balanced daily diet, fats should make up around 20% of total caloric intake.

Types of Fats

When fats break down in the body, they release fatty acids. Based on the type of fatty acids, we distinguish:

• Saturated fats

• Unsaturated fats

Unsaturated Fatty Acids

Loosely speaking, unsaturated fats are considered the “good fats.”
These include plant-based fats found in oils such as sunflower, olive, and rapeseed oil, and also in nuts and seeds.
Unsaturated fats are also present in fish oil. They can be further categorized into monounsaturated and polyunsaturated fatty acids.

Monounsaturated Fatty Acids

These fats help regulate blood cholesterol levels, support cardiovascular health, and contribute to brain function, proper growth, and development.

Polyunsaturated Fats: Omega-3 and Omega-6

Omega-3 fatty acids are found in oily fish such as sardines, anchovies, mackerel, tuna, and herring. They’re also present in eggs, flax seeds, walnuts, and soy, and are shown to be highly beneficial for maintaining health.

Omega-6 fatty acids are found in sunflower seeds, sesame, meats, and baked goods.
The optimal intake ratio between omega-3 and omega-6 fatty acids is 1:3.

Saturated Fatty Acids

Sources of saturated fats include animal fats, palm oil, coconut oil, margarine, and mayonnaise.
A simple way to recognize them is that they solidify at room temperature.

In modern nutrition, saturated fats have long been labeled as “unhealthy,” but more recent studies—and traditional wisdom—point to their usefulness.
For example, dairy fats and coconut oil have valuable health roles, and even pork fat, which was once practically banned from healthy diets, is now being reassessed.

However, the true villain in the fat story is trans fat.

Trans Fatty Acids

Trans fats are technically a type of unsaturated fat, but structurally different from the naturally occurring ones.
They should not be confused with healthy unsaturated fats, which can be beneficial—even essential.
Trans fats, by contrast, have negative effects and no nutritional necessity.

They are rarely present in natural, unprocessed food. In nature, small amounts are formed in the digestive systems of ruminants (cows, sheep), but they’re virtually absent in other natural sources.

How Trans Fats Are Created

Trans fats are mostly a product of industrial food processing, created in two main ways:

1. Hydrogenation – A process known as partial hydrogenation is used to make oils more stable and extend shelf life. This creates trans fats as a byproduct.

2. Cooking/Frying – Trans fats also form during high-heat frying or baking with certain vegetable oils.

They’re most abundant in:

• Margarine

• Sweets

• Chips and snacks

• Fast food

• Baked goods

• Processed industrial food in general

The human body cannot properly use trans fats, and they interfere with the absorption of healthy polyunsaturated fats.
They are directly linked to high cholesterol, triglycerides, and serious health conditions.

If possible, completely eliminate them from your diet.