Nutrition trends around fat have shifted dramatically — from low-fat diets in the 1990s to keto in the 2000s, to current concerns around seed oils. The reality is more nuanced: fats are essential, but the type and context matter.
The Role of Fats
Fats play several important roles in the body. They provide a concentrated source of energy, help absorb fat-soluble vitamins (A, D, E, and K), support cell structure, and supply the building blocks needed to produce cholesterol — which is essential for making bile and hormones.
Caloric Density
Fat is more calorie-dense than carbohydrates or protein, providing 9 calories per gram compared to 4. It's also highly palatable and easy to overconsume — especially in processed or fried foods where fat is less visible.
Types of Fat
Saturated vs. Unsaturated Fats
Saturated fats are typically solid at room temperature and are found in foods like red meat and full-fat dairy. Diets high in saturated fat can raise LDL ("bad") cholesterol, which is associated with plaque buildup in arteries.
Unsaturated fats, on the other hand, are usually liquid at room temperature and come from plant-based sources like olives, avocados, nuts, and seeds. These fats are generally considered heart-healthier choices, as they don't raise our LDL.
Omega-3 and Omega-6 Fatty Acids
Both omega-3 and omega-6 fats are essential, meaning they must be obtained through food.
- Omega-3s (found in fatty fish, flaxseeds, and chia seeds) help reduce inflammation and support heart health
- Omega-6s (found in nuts, seeds, and plant oils) can also support heart health when they replace saturated fats
These fats share metabolic pathways, and modern diets often contain a much higher proportion of omega-6s, particularly from processed and fried foods.
The goal isn't to avoid omega-6s, but to create balance by:
- Including omega-3-rich foods regularly
- Limiting heavily processed and fried foods
The takeaway: Fat isn't bad for you, but the quality of fat you are consuming is important. Limit saturated fats and fried foods, and prioritize unsaturated fats and omega-3s.