Fat spent thirty years as the villain of nutrition and the advice has since changed considerably. Here's roughly where things stand now.
What fat does
It's a concentrated energy source, it's structural in every cell membrane in your body, it's required to absorb vitamins A, D, E and K, and it's the raw material for a number of hormones. It also carries flavour and contributes to feeling satisfied rather than merely full.
The low-fat era produced a lot of food that left people hungry an hour later, which is part of why it didn't work.
The types, briefly
Monounsaturated — olive oil, avocado, most nuts. Consistently associated with good outcomes; the backbone of Mediterranean eating patterns.
Polyunsaturated — splits into omega-3 and omega-6, and this is the interesting part (below).
Saturated — meat, dairy, coconut, palm. The most argued-over category in nutrition. The position has softened from "avoid" to something more nuanced: what you replace it with matters more than the amount alone. Replacing saturated fat with refined carbohydrate achieves nothing; replacing it with unsaturated fat looks beneficial.
Trans fats — the one genuine consensus. Industrially produced trans fats are harmful and have been banned in Canada since 2018.
Omega-3, which is the one worth understanding
There are three that matter, and they are not interchangeable:
- ALA — from flax, chia, walnuts, hemp. Plant-based.
- EPA and DHA — from oily fish and algae. These are the forms your body actually uses in cell membranes and in resolving inflammation.
Your body can convert ALA into EPA and DHA, but the conversion is inefficient — commonly cited as under 10% for EPA and considerably less for DHA. Which means eating flax is not nutritionally equivalent to eating salmon, however often that's implied.
If you don't eat fish, algae-derived EPA/DHA supplements exist and are the sensible route — that's where the fish get it from in the first place.
The omega-6 question
You'll read that modern diets have a badly skewed omega-6 to omega-3 ratio, and that this drives inflammation. The intake shift is real — industrial seed oils changed the ratio substantially over the last century. Whether correcting the ratio produces the health effects claimed is much less settled than the confident version you'll see online.
My practical read: rather than fearing omega-6, most people would do better simply eating more omega-3. Oily fish twice a week does more than avoiding sunflower oil.
Fish oil supplements
Worth considering if oily fish genuinely isn't happening twice a week. Look for the EPA and DHA amounts on the back rather than the total fish oil on the front — they're often very different numbers. Rancidity is a real problem in this category; if it smells strongly fishy, it's oxidised.
Speak to your pharmacist before starting fish oil if you take any blood thinner. Omega-3 affects platelet function and the interaction is real.
This is general nutrition education, not medical advice, and it isn't intended to diagnose, treat, cure or prevent any condition. If you're pregnant or breastfeeding, taking medication, or managing a diagnosed condition, talk to your doctor or pharmacist before making changes.
Written by Mellissa Wallace, Registered Holistic Nutritionist, Okanagan BC.
More in Vitamins & Minerals
- ProteinHow much you actually need, why breakfast is the meal that matters, and whether powders are worth it.6 min
- IronOne of the most common shortfalls in Canada — and the one supplement you should never take on a guess.6 min
- Vitamin B12The one nutrient plants genuinely cannot provide — and the case where a supplement is straightforwardly the right answer.5 min