The Fats that Keep you Lean

We all know that nutrition is complicated — but sometimes the simplest shifts can have the biggest impact on how we feel, how hungry we are, and even how easily we burn body fat. One of the most important (but most overlooked) factors is the balance between omega-6 and omega-3 fats.

This isn’t another “good fat/bad fat” lecture. It’s about the biochemical signals these fats send to the brain and body — signals that can either support a fast, efficient metabolism… or slow everything down.

Much of the insight in this article is inspired by the work of Dr Andrew Jenkinson, bariatric surgeon and author of Why We Eat (Too Much), who explains why our modern diets, flooded with omega-6, make weight loss harder than it needs to be.

The Omega Imbalance: Why We’re Drowning in Omega-6

For most of human history, we ate a roughly 1:1 ratio of omega-3 to omega-6.

Today, thanks to ultra-processed foods and the rise of industrial seed oils (sunflower, rapeseed/canola, soybean, corn, safflower), the ratio has shifted to anywhere from 10:1 to 25:1 in favour of omega-6.

This imbalance matters, because omega-6 and omega-3 send opposite metabolic messages.

Omega-3: The “You’re Safe, You’re Full” Signal

Omega-3 fats — especially EPA and DHA from oily fish — do far more than reduce inflammation.

They send a powerful hormonal message to your brain:

• We have enough nutrition

• We are satisfied

• It’s safe to use stored body fat as fuel

In other words, omega-3 promotes metabolic safety. When the body feels safe, your metabolism naturally speeds up. You burn more calories at rest. You feel fuller sooner. Cravings calm down.

This is why Dr Jenkinson emphasises increasing omega-3 intake — because it directly improves your metabolic gearing.

Omega-6: The “Store Fat and Slow Down” Signal

Omega-6 isn’t evil — we need some. The problem is too much, especially from highly processed seed oils.

When omega-6 floods the system, it signals the brain and fat cells:

• We may be under threat

• Store energy

• Slow the metabolic rate

• Increase hunger and cravings

This is the exact opposite of what most people want, especially when they're trying to lose weight or improve metabolic health.

And here’s the important part:
These metabolic signals happen even without many calories.

This is why diets promoting “1-calorie spray oils” made from refined sunflower or rapeseed oil are misleading. Sure — they don’t add many calories. But they still send an omega-6–dominant metabolic message that tells the body to downshift metabolism and burn less fat.

Calories count, but hormonal and inflammatory signals count more.

Seed Oils and Inflammation

Excess omega-6, particularly from refined seed oils, contributes to chronic low-grade inflammation. This can show up as:

• bloating

• joint pain

• skin irritation

• fatigue

• stubborn weight gain

• hormonal imbalance

These oils oxidise easily (especially when heated), generating inflammatory by-products that burden the body.

10 Everyday Foods That Surprisingly Contain Seed Oils

Even if you avoid deep-fried foods and don’t cook with vegetable oil, seed oils often sneak in where you least expect them.

You’ll find them in:

1. Hummus (supermarket varieties)

2. Pesto and jarred pasta sauces

3. Plant-based milks and creamers

4. Protein bars and “health” snacks

5. Low-fat yoghurts

6. Tortilla wraps and flatbreads

7. Granola and “healthy” cereals

8. Ready-made soups

9. Gluten-free baked goods

10. Most salad dressings and mayonnaise

This is why people think they’re eating “clean” but still feel inflamed, hungry, or stuck in a weight-loss plateau.

Simple Swaps That Make a Huge Difference

You do not need to cut out fats. You just need to prioritise whole-food, stable, naturally occurring fats.

Better Choices for Cooking & Eating

• ✔️ A little real butter is better than a lot of low-fat spread

• ✔️ Extra virgin olive oil beats rapeseed oil — every time

• ✔️ Goose fat or beef dripping are more stable, less inflammatory options for frying

• ✔️ Oily fish (salmon, sardines, mackerel) boosts omega-3

Avoid When Possible

• ✖️ Sunflower oil

• ✖️ Rapeseed/canola oil

• ✖️ Soybean oil

• ✖️ “Vegetable oil” blends

• ✖️ Low-fat spreads

• ✖️ 1-kcal cooking sprays made from seed oils

These small changes help restore your metabolic balance, reduce inflammation, and support natural fat-burning.

Final Thoughts

Understanding omega-6 and omega-3 isn’t about demonising fats. It’s about learning what signals your body listens to — and how modern food quietly hijacks those signals.

You deserve a metabolism that works with you, not against you.

Prioritise whole foods. Eat real fats in sensible amounts. Boost your omega-3s. Cut back on industrial seed oils where you can.

Your body will feel the difference — often within weeks.

IF you found this interesting I highly recommend the book "Why we eat too much" as this is just a very brief intro to the subject. The book is very easy to read and makes all the science simple to understand.