The Truth About Fats: Fuel, Function and Food Myths

For decades, fat was unfairly demonised. Labelled the dietary villain behind rising obesity rates, heart disease, and countless other issues, it was stripped from food products and replaced with sugar, preservatives, and marketing spin. But the truth is, fat is essential, not optional, for good health, high performance, and long-term wellbeing.

If you're training outdoors, lifting in the park, hiking the hills, or just trying to feel stronger, leaner, and more energised. Understanding how fat works in the body is non-negotiable.

🧠 Fats and Your Brain & Nervous System

Let’s start where fat really shines, your brain.
Roughly 60% of the brain is fat, and it's rich in Omega-3 fatty acids, it is also the hungriest organ in your body burning around 60% of all the calories you consume. These Omega-3 fatty acids are vital for:

• Neural signalling

• Cognitive performance

• Mood regulation

• Memory and focus

Fat also surrounds and insulates your central nervous system. It’s a vital part of the myelin sheath, a fatty layer that wraps around nerves to help electrical signals fire properly. Without enough healthy fat in your diet, your mental sharpness, reflexes, and ability to focus can all take a hit, which matters if you're on the move, lifting, or learning new movement patterns.

🔥 Fat as a Fuel Source

Fat is your body’s preferred energy source at rest and during low to moderate intensity activity. Unlike carbohydrates, which burn fast and require constant top-ups, fat is a slow-burning fuel, ideal for:

• Walking

• Steady-state runs

• Long hikes

• Recovery days

Here's how it works:
Your body takes stored or dietary fat and, in the presence of oxygen, breaks it down to produce ATP, Adenosine Triphosphate, your muscles’ energy currency. This process is called beta-oxidation, and it kicks in when oxygen is plentiful and intensity is lower.

So, whether you're trekking up Box Hill with a rucksack or grinding out a long kettlebell circuit, your body is tapping into fat stores alongside carbs to keep you moving.

🛡️ Fats Protect & Insulate Your Body

Dietary fat doesn’t just help you do things,it also protects you from things.

• It insulates your body, helping maintain body temperature during cold sessions outdoors (very handy in a frosty Vicky Park morning).

• It cushions and protects vital organs like your liver, kidneys, and heart.

• It supports healthy skin, hair, and nails, all of which take a hit during periods of stress, intense training, or poor nutrition.

In simple terms: fat gives your body the padding, protection, and warmth it needs to function at its best.

🧂 Cooking with Real Fats — Why It Matters

Your body doesn’t just need fat, it needs real, stable, traditional fats.

Here’s a quick guide to some of the best fats to cook with, many of which you were probably told to avoid:

✅ Whole Butter

Great for low to moderate heat. Contains fat-soluble vitamins like A and D, and gives food flavour and richness.

✅ Clarified Butter (Ghee)

Ghee has the milk solids removed, so it’s more heat-stable. Perfect for higher-temperature cooking and ideal for those sensitive to dairy.

✅ Duck Fat

Incredible flavour, high in monounsaturated fats, and fantastic for roasting veg or potatoes. It’s been used in traditional cuisines for centuries.

✅ Lard

Rendered pork fat. Once a staple in British kitchens, lard is stable at high heat and full of vitamin D when sourced from pasture-raised pigs.

✅ Beef Dripping

Rich, flavourful, and great for deep roasting. Like lard, dripping is heat-stable and perfect for long, slow cooking.

All of these are far superior to the ultra-processed vegetable and seed oils that flood modern processed foods. Oils like sunflower, soybean, and corn oil, which are chemically unstable and pro-inflammatory when heated.

✅ Which Fats to Include

Good:

• Oily fish (salmon, mackerel, sardines)

• Avocados

• Nuts and seeds

• Olive oil

• Whole and clarified butter

• Animal fats from pasture-raised sources

Use sparingly or avoid:

• Trans fats (found in processed snacks, baked goods, cheap margarine)

• Highly refined seed oils (corn, soybean, rapeseed, especially if reheated repeatedly)

🍳 How to Add Healthy Fats Into Your Day

• Cook your eggs in butter or ghee

• Roast veg in duck fat or olive oil

• Add avocado or olives to salads

• Mix chia or flax seeds into porridge

• Snack on nuts or smear apple slices with nut butter

• Include oily fish twice a week

Personally, I start most days with eggs, sourdough, sautéed spinach and tomatoes — the yolks alone are packed with healthy fats, and paired with good carbs, it keeps me satisfied for hours.

💪 Fat and Training at Eastside

Whether you’re pushing hard on the kettlebells, smashing circuits in the park, or getting the miles in on a Sunday hike, fat is fuelling you more than you realise.

It’s not just calories. It’s structure. It’s insulation. It’s focus and recovery and performance.

And it’s time to stop fearing it.