If you’re anything like me, you’ve probably stood in a supermarket aisle, scrutinising labels, trying to figure out whether to avoid fat like the plague or embrace it like a long-lost friend. For decades, we were told “fat makes you fat.” Full stop. No nuance. But that’s not the full story. And here’s the kicker: it’s not fat alone that’s the real problem – it’s fat combined with sugar that wreaks havoc on your body.
I’m not a doctor, but I’ve spent years reading, experimenting, and living through my own ups and downs with weight, energy levels, and health. What I’ve discovered is this: fat is not your enemy. In fact, it can be your ally. But pair it with sugar, and it becomes the villain in a tragic health drama.
Let’s unpack why.
The Demonisation of Fat
First, a bit of history. Back in the 1970s and 80s, health authorities started blaming dietary fat for rising heart disease rates. This led to a tidal wave of “low-fat” products flooding the market. Yogurts, snack bars, ready meals all promised health simply because they cut the fat. But here’s the dirty little secret: they replaced the fat with sugar or refined carbs to keep the taste palatable.
And that’s where we went wrong.
Studies today show fat alone, especially healthy fats, does not automatically clog your arteries or pile on pounds the way we once feared. For instance, the Mediterranean diet, rich in olive oil, nuts, and fatty fish, has been shown repeatedly to reduce heart disease risk and improve health outcomes. You can read about this in more detail on Wikipedia’s page about the Mediterranean diet.
So, why do so many people still believe fat is the enemy?
Because the science was oversimplified. Fat has over twice the calories per gram compared to carbs or protein, so it seemed logical to blame it for weight gain. But calorie math isn’t that simple.
The Biological Role of Fat
Let’s get real. Your body needs fat. It’s not just a blob of insulation around your waist.
Here’s what fat actually does for you:
| Function | Why It Matters |
|---|---|
| Hormone Production | Fats help create hormones, including sex hormones like testosterone and estrogen. |
| Cell Structure | Every cell membrane in your body is made from fat. |
| Vitamin Absorption | Vitamins A, D, E, and K are fat-soluble – you can’t absorb them without fat. |
| Brain Health | Your brain is roughly 60% fat. Fat helps maintain cognitive function and mood stability. |
| Energy Source | Fat is a slow-burning fuel, keeping you fuller for longer. |
In other words, fat is essential for staying alive, thinking clearly, and feeling good. Demonising it was a huge mistake.
Why Fat Alone Doesn’t Make You Fat
People often say, “Fat has more calories, so eating fat will make me fat.” I used to think the same. But real life is more complicated. Fat alone tends to be satiating, meaning it makes you feel full faster and longer. Think about how satisfied you feel after eating an avocado or handful of nuts, versus a bag of crisps.
When you eat healthy fats, your insulin response stays relatively low. Insulin is a hormone that tells your body to store energy. Spiking it repeatedly, especially with sugar, can lead to fat accumulation.
Low insulin = less fat storage.
That’s why low-carb or keto diets, which are higher in fat, help many people lose weight – even though they’re eating more fat.
So fat isn’t inherently fattening. But… combine it with sugar, and it’s a different story.
The Perfect Storm: Sugar and Fat Together
Here’s the twist. Sugar and fat together create a hyper-palatable combo that hijacks your brain and metabolism.
Ever noticed how pure fat or pure sugar alone isn’t quite as irresistible as foods that mix them? Think:
- Ice cream
- Doughnuts
- Pastries
- Milk chocolate
- Pizza
These foods light up your brain’s reward centre like fireworks. The combination triggers massive dopamine release, making you crave more.
It’s no accident. Processed food companies engineer these combinations to make you overeat.
How Sugar and Fat Together Cause Damage
The sugar-fat combo is dangerous for a few reasons:
1. Insulin Spikes
Sugar causes a rapid rise in blood glucose, which triggers insulin. When fat is also present, your body is primed to store that energy as body fat because insulin signals your body to “pack it away.”
2. Fat Storage Priority
Your body prioritises burning glucose first. So if you eat fat and sugar together, the sugar gets used up for immediate energy, and the fat goes into storage.
Result: more body fat.
3. Chronic Inflammation
Ultra-processed foods with sugar and fat often contain seed oils, trans fats, and additives that promote inflammation in the body. Chronic inflammation is linked to obesity, diabetes, and heart disease.
4. Gut Dysbiosis
Sugar and processed fats can harm your gut bacteria. A healthy gut regulates weight and mood, so this is a bigger deal than most people realise.
For a deeper dive, check out this article on the metabolic effects of sugar and fat together on PubMed.
Real-Life Example: The Doughnut
Let’s talk about the humble doughnut.
One plain doughnut might contain:
- 15-20g of fat
- 20-30g of sugar
- Refined flour
- Seed oils
It’s:
- High calorie
- High carb
- High fat
- Low in nutrients
The sugar spikes insulin. The fat provides excess energy. Together, they make it almost impossible to stop at one. That’s why you can polish off half a box of doughnuts and still want more. Your hunger cues have been hijacked.
Contrast that with eating a tablespoon of pure olive oil. It’s pure fat, but are you likely to eat ten tablespoons in a row? Nope. Because fat on its own doesn’t trigger the same addictive response.
How to Eat Fat the Right Way
So what should you do?
Don’t fear fat – but be strategic.
Here’s how:
- Choose healthy fats: avocado, olive oil, nuts, seeds, fatty fish, grass-fed butter.
- Limit processed fats: avoid hydrogenated oils, trans fats, and highly refined seed oils in processed foods.
- Eat fat with protein and fibre: This keeps you full and stabilises blood sugar.
- Avoid pairing fat with sugar: skip pastries, cakes, ice cream, and sugary coffee drinks loaded with cream and syrups.
- Listen to your body: Healthy fats should make you feel nourished, not sluggish.
Why We Keep Craving Sugar and Fat Together
This is the tough part. Your brain is wired to crave energy-dense foods. From an evolutionary perspective, sugar and fat meant survival. They were rare and valuable.
In modern times, they’re everywhere. We’re surrounded by cheap, calorie-dense junk that exploits ancient biology. The food industry knows this and designs foods that keep you coming back.
It’s not a moral failing if you love doughnuts. It’s biology. But knowledge is power.
The Weight Loss Factor
If you’re trying to lose weight, here’s the blunt truth:
- Fat alone won’t derail you if eaten in moderation.
- Sugar and fat together will.
Eating fat helps many people stick to their calorie goals because they feel satisfied. But if your fat comes in the form of cheesecake or cronuts, forget it. The sugar-fuelled cravings will sabotage your plan.
That’s why some people thrive on keto diets – they remove sugar and let fat do its thing. But you don’t have to go full keto to reap the benefits. Simply cut back on foods where sugar and fat are combined. That one step can change your entire health trajectory.
My Personal Journey
I used to be a low-fat fanatic. I’d buy “low-fat” yogurts, thinking they were healthy, without realising they were packed with sugar. I was always hungry, had crazy energy crashes, and felt miserable.
Once I started eating more healthy fats – avocado, nuts, oily fish – and cut down on sugar, everything changed:
- My energy stabilised.
- Cravings disappeared.
- I felt fuller on fewer calories.
- My weight dropped and stayed stable.
I’m not perfect. I still love the occasional piece of cake. But now I know why it’s so addictive – and I treat it like a treat, not a staple.
Simple Swaps You Can Make
Here’s how to reduce the fat-sugar combo in your diet:
| Swap This | For This |
|---|---|
| Ice cream | Greek yoghurt with berries |
| Milk chocolate bar | Dark chocolate (85% cocoa) |
| Sweet pastries | Nuts or seeds |
| Flavoured coffee drink | Black coffee with cinnamon |
| Sugary salad dressing | Olive oil + vinegar |
These small changes help break the cycle of craving.
Final Word: Fat is Your Friend… Within Limits
Let’s bring it back to the core message: Fat is not your enemy. It’s necessary, nourishing, and can help you feel your best. But sugar and fat together create a perfect storm that’s hard to resist – and hard on your health.
So:
- Eat healthy fats.
- Limit added sugars.
- Keep sugar and fat separate as much as possible.
Do that, and you’ll be ahead of 90% of the nutrition confusion out there.
Your body will thank you.
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