Introduction to fats

Fats – A Macronutrient

  • Essential part of the diet, should provide about 30% of daily energy intake.

  • Energy value: 37 kJ per gram.

  • Fats: solid at room temperature.

  • Oils: liquid at room temperature (25°C).

Classification of Fats

  • Saturated fats

  • Unsaturated fats (monounsaturated & polyunsaturated)

  • Trans fats

Saturated Fats

  • Usually solid at room temperature, high melting point.

  • Food sources:

    • Red meat

    • Dairy (milk, cream, cheese, butter)

    • Coconut & palm oil

    • Pastries, cakes, deep-fried foods

  • Health risk: increase cholesterol → higher risk of heart disease.

Unsaturated Fats – Monounsaturated

  • Soft or liquid at room temperature, low melting point.

  • Food sources:

    • Seed oils (sunflower, safflower, corn)

    • Avocado

    • Olive oil

    • Legumes

  • Should replace saturated fats in the diet.

Unsaturated Fats – Polyunsaturated

  • Liquid at room and fridge temperature, lowest melting point of fats.

  • Contain omega-3 fatty acids with health benefits:

    • Lower cholesterol

    • Reduce blood pressure

    • Lower risk of heart disease and stroke

    • Important for development and immune system

  • Food sources:

    • Peanut oil, canola oil

    • Sunflower seeds

    • Oily fish (mackerel, herring, salmon, sardines, tuna)

Trans Fats

  • A type of unsaturated fat, artificially modified by hydrogenation.

  • Created by adding hydrogen to vegetable oils → more solid and longer shelf life.

  • Also form through high-temperature heating/frying.

  • Food sources:

    • Naturally in butter, cheese, meat

    • Processed foods (pastries, doughnuts, cakes, chips, margarine)

  • Health risks:

    • Raise bad cholesterol (LDL), lower good cholesterol (HDL)

    • Increase risk of heart disease, stroke, type 2 diabetes

    • Linked to inflammation and metabolic disorders

Molecular/Chemical Structure

  • Fats made of Carbon (C), Hydrogen (H), Oxygen (O).

  • Structure: triglyceride molecule = 1 glycerol + 3 fatty acid chains.

Functions of Fats

  • Aid absorption of fat-soluble vitamins (A, D, E, K).

  • Help produce hormones.

  • Provide heat and energy.

  • Support cell growth.

  • Protect bones and vital organs.

  • Improve food texture (easier to chew & swallow).

Effects of Fat Imbalance

  • Excess fat consumption: linked to obesity, heart disease, and other health risks.

  • Deficiency of fats: poor absorption of vitamins, impaired hormone production, weakened immune system.