Dietary Fat Explained
Quick answer
Dietary fat provides energy, supplies essential fatty acids, helps absorb fat-soluble vitamins and contributes to cell structure and flavour. The type and food source of fat matter.
Fat has several jobs
It supports cell membranes, carries fat-soluble vitamins and provides essential fatty acids the body cannot make.
Types of fat differ
Unsaturated fats are common in nuts, seeds, fish, avocado and many plant oils. Saturated fat is more concentrated in some animal fats and tropical oils. Industrial trans fats have been restricted in many countries.
Replacement matters
Nutrition guidance often recommends replacing foods high in saturated fat with foods supplying mostly unsaturated fat—not merely removing fat and adding refined carbohydrate.
Replacing butter with olive or canola oil changes the type of fat. Replacing salmon with a sugary snack lowers fat but does not necessarily improve the meal.
Key terms
| Unsaturated fat | Fat with one or more carbon-carbon double bonds. |
|---|---|
| Saturated fat | Fatty acids without double bonds. |
| Essential fatty acid | A fatty acid that must come from food. |
| Fat-soluble vitamins | Vitamins A, D, E and K. |
Common mistakes
- Assuming all fat has the same effect. Unsaturated and saturated fats come from different foods and are not interchangeable.
- Choosing “fat-free” products automatically, even when they are not more satisfying or nutritious.
- Forgetting that nuts, seeds, fish and oils can provide useful fats even though they are energy-dense.
Practical takeaway
Pay attention to the type and food source of fat. Replacing some saturated-fat-rich foods with unsaturated-fat-rich foods is more useful than trying to remove all fat.