One day, you hear that olive oil is the ultimate health fix and a hero of the Mediterranean diet. The next, coconut oil is seen as the only oil worth eating for optimal health. With so many conflicting claims and diet trends, it’s easy to feel confused about which fats deserve a regular place in your diet and which are best kept as occasional treats.
In this article, we demystify dietary fats and explore why they are essential for good health. We also break down the main types of fats and help you make informed, confident choices the next time you reach for oil or butter at the supermarket.
Fats: their history and the confusion around them
It’s completely normal to feel unsure about which fats you should be eating, or even if you should be eating them at all. Over the years, health campaigns and diet trends have sent us mixed messages about fat. Some have called it unhealthy and dangerous, while others have praised it as an essential part of a balanced diet. No wonder so many of us feel confused.
Let’s take a look at the two sides of the story: the fat lovers and the fat haters.
The fat lovers
Throughout history, fats have been loved for their flavour, richness and the way they connect us to food traditions. In northern countries, fatty foods like meat are a staple during the winter months, while in Mediterranean countries, olive oil is closely tied to family traditions and heritage. From the golden butter of local dairies to the savoury comfort of lard, fat has always been about more than just taste. In recent years, people have started to embrace it again, celebrating natural and traditional ways of cooking and eating.
Popular “fat-loving” diets and movements include:
- Paleo diet: focuses on eating like early hunter-gatherers, with meat, eggs, natural fats, fruit and vegetables while cutting grains and processed foods.
- Keto diet: a high-fat, very low-carbohydrate diet.
- Carnivore diet: a more extreme version of keto, consisting almost entirely of animal products such as meat, butter, and animal fat.
These fat-focused trends often present themselves as a move away from processed foods and a return to simple eating. But they need to be approached carefully, as they can leave out important parts of a healthy, balanced diet, such as healthy carbohydrates, fibre, and fruit and vegetables.
The fat haters
Low-fat diets really took off in the late 20th century, especially in the United States. Government guidelines in the 70s and 80s told people to cut down on fat to protect their hearts and control their weight. Shops were soon full of low-fat and fat-free products, but the problem was that manufacturers often replaced the fat with sugar or refined carbs. People ended up eating just as many calories and, unsurprisingly, got fatter. Nowadays, experts say it’s not just about how much fat you eat, but the type of fat, and that balance and moderation matter more than strict rules.1
In the UK, growing links between fitness and health led to the rise of gyms and exercise classes, including aerobics in the 1960s. By the 1980s, low-fat diets had become popular, following the introduction of government dietary guidelines.2
What began as health campaigns against fat ultimately blurred the line between nutrition and marketing, leaving many people misinformed about what truly makes up a balanced diet.
What fats actually are
Fats are one of the three main macronutrients, alongside protein and carbohydrates. Think of them as your body’s concentrated energy source. Fats are made of something called triglycerides. They have a main part with three chains attached, and they store energy for your body.
But fats do more than just give you energy, and they have both benefits and risks. Let’s take a closer look.
The benefits of healthy fats
Healthy fats do a lot for your body. They support your heart and brain, provide energy, and help you feel full for longer. They also help your body produce hormones, build cell membranes, support metabolism, and absorb fat-soluble vitamins like A, D, E, and K.3 4
Healthy fats also help raise the “good” cholesterol in our blood, which then helps get rid of the “bad” cholesterol.
In short, we can’t live without them. The key is knowing which fats to eat regularly and which to enjoy only occasionally to keep your heart, metabolism, and overall wellbeing in check. More on this later.
The risks of unhealthy fats
Eating too many unhealthy fats can raise “bad” cholesterol and increase the risk of heart disease and inflammation. Choosing healthier fats and keeping portions reasonable is the best way to stay balanced and protect long-term health.
The question is, which fats are healthy and which are unhealthy? Let’s unpack this in the next part of the article.
Wait, cholesterol can be good?
Yes, good cholesterol exists! It’s called HDL or high-density lipoprotein. This is the “good” cholesterol that helps clear out the cholesterol your body doesn’t need.
On the other hand, LDL or low-density lipoprotein is the “bad” cholesterol that contributes to plaque buildup in your arteries, which can increase the risk of heart attacks and strokes.
What are the 3 main types of fats?
1. Unsaturated fats: MUFAs and PUFAs
Unsaturated fats, found in foods like olive oil, nuts, seeds, avocados, and oily fish, are the “good fats” your body needs. They support heart health, help maintain healthy blood pressure and circulation, and can improve blood sugar and cholesterol levels.
MUFAs
Diets rich in monounsaturated fats (MUFAs) can support weight loss and help lower some of the risk factors for cardiovascular disease, keeping your heart healthy. Foods high in MUFAs, especially olive oil, may also help reduce inflammation and improve insulin sensitivity.5
Found in food such as: olive oil, raw almonds, avocado, dry roasted unsalted cashews, pistachios
PUFAs: Omega fatty acids
Polyunsaturated fats (PUFAs), including omega-6 and omega-3, are essential for health. They are particularly great for supporting your heart, muscles, and brain:6 7
| Type of PUFA | Benefits |
| Omega-6 | Supports heart health Helps muscles and brain work properly |
| Omega-3 | Reduces inflammation Protects the heart May lower the risk of blood clots DHA (a type of omega-3) is important during pregnancy for baby’s brain and eye development; supports brain function, mood, and memory in adults |
Found in food such as: flaxseed, chia seeds, walnuts, oily fish
What is oily fish?
Not all fish are the same when it comes to healthy fats. Oily fish, like salmon, mackerel, sardines, and trout, have those good omega-3 oils running through their flesh — that’s what gives them their richer flavour and darker colour.
Non-oily fish, such as cod or haddock, keep most of their fat in the liver instead, so their flesh is lighter and leaner.
Both are great for you, but oily fish give you that extra boost of heart-healthy omega-3s, which is why it’s worth adding them to your meals once or twice a week.
2. Saturated fats
Saturated fats are usually solid at room temperature and can raise your “bad” LDL cholesterol if you have too much. A small amount is fine for most people, but eating a lot can increase the risk of heart disease.
Experts recommend replacing some saturated fats with healthier unsaturated fats, like olive oil, nuts, or oily fish, which can reduce the risk of heart disease.
Saturated fat may also influence inflammation, blood clotting, and heart rhythm, although scientists are still unclear about how much it impacts these.8
Found in food such as: butter, cheese, fatty meats, coconut oil, palm oil
Saturated, unsaturated… what’s the difference?
It all comes down to chemistry! Saturated fats have no double bonds, making them solid at room temperature (like butter or cheese).
Unsaturated fats have one or more double bonds, making them liquid and usually healthier, like olive oil.
If there’s one double bond, it’s called monounsaturated fat (from mono, meaning one) — like in avocados or olive oil.
If there are several, it’s polyunsaturated fat (from poly, meaning many) — found in oily fish, walnuts, and seeds.
3. Trans fats
Trans fats are a type of fat made when liquid oils (like vegetable oil) are turned into solid fats, such as the old-style margarines, through a process called hydrogenation. This used to be done to give foods a longer shelf life and a better texture, but it also created artificial trans fats, which are harmful to health.
Trans fats can raise “bad” LDL cholesterol and lower “good” HDL cholesterol, increasing the risk of heart disease. Because they offer no health benefits and can be dangerous, experts recommend keeping them as low as possible — ideally under 1% of your daily calories.9
The good news is that in the UK and EU, most industrially produced trans fats have now been removed from food. Since April 2021, foods sold in the EU must contain no more than 2g of industrial trans fat per 100g of fat.10 This means most supermarket products are now virtually trans fat-free.
However, trans fats can still appear naturally in small amounts in meat and dairy from cows, sheep, and goats. These are similar chemically and should also be eaten in moderation.
And what about margarine? It’s had a bad reputation, but things have changed. Modern margarines now contain almost zero trans fats and can actually help lower cholesterol, according to Professor Nita Forouhi from the University of Cambridge.11 So it can be part of a healthy diet, especially if you use it instead of butter or ghee.
You might still find trans fats in:
- Fried and baked foods (like pies, pastries, and biscuits)
- Some takeaway and processed foods made with cheap oils
- Meat and dairy from cows, sheep, and goats
Tip: Check the ingredients list — if you see “partially hydrogenated oil,” it’s best to steer clear.
Is coconut oil healthy?
Coconut oil gets a lot of attention, but its health benefits may be questionable. It’s very high in saturated fat - even more than butter. Using it now and then is fine, but it’s better to go for more accessible options that are lower in saturated fat, like olive or rapeseed oil.
How much fat should I eat?
Health experts, including the World Health Organization (WHO), emphasise that both the amount and type of fat you eat matter for good health. WHO recommends that adults keep their total fat consumption to around 30% of daily energy or less. For everyone aged 2 and older, the majority of fats should come from unsaturated sources, while saturated fats should make up no more than 10% of total energy, and trans fats should be kept very low, at no more than 1% of total energy.12
Eating too little fat can be just as problematic, as it may reduce levels of HDL, the “good” cholesterol, and make it harder for your body to absorb certain vitamins.
Here’s a simple guide to the main types of fats, how much you should eat, and the best foods to get them from:13 14
| Type of Fat | Recommendations & Daily Amount | Where to Find & Top Tips |
| Saturated fats | Keep as low as possible – ideally <10% of daily calories. UK guidance: men ≤30 g, women ≤20 g, children even less. | A 100 g portion of bacon or a couple of tablespoons of butter contains roughly 14 g of saturated fat – around half of your daily allowance. Enjoy these foods occasionally and in small amounts. |
| Trans fats | Mostly artificial; should be avoided. WHO recommends adults to consume no more than 1% of their daily calories from trans fats – about 2 g for someone eating 2,000 calories. | Swap biscuits for nuts, limit fast food, and check margarine labels. |
| PUFAs – Omega-3 | Men are recommended ~1.6 g/day and women ~1.1 g/day. | 1-2 portions of oily fish/week (salmon, sardines, mackerel, trout), or plant sources like flaxseed and walnuts. |
| PUFAs – Omega-6 | Men are recommended ~17 g/day and women ~12 g/day. | A teaspoon of sunflower or corn oil in cooking, sesame seeds, roasted soybeans, or a small handful of nuts. |
| MUFAs | Recommended that MUFAs make up around 20% or less of your total daily calories – for a 2,000-calorie diet, that’s about 400 calories. | Include them naturally throughout the day: a tablespoon of olive oil in a salad, half an avocado on toast, and a small handful of almonds. |
How to add more healthy fats to your diet
Try to reduce the amount of saturated fats and trans fats you eat in a day, and swap them for unsaturated or “healthy” fats instead. A handy rule of thumb is about a thumb-sized portion of healthy fat per meal.
Easy swaps:
- Drizzle olive oil on roasted veggies, instead of butter
- Add avocado to salads and sandwiches, rather than bacon
- Snack on a handful of nuts or seeds, instead of crisps
- Try to include fish a few times a week, instead of eating only meat
How to eat fats more sustainably
Fats matter not just for your health, but for the planet too. Here are a few simple ways to eat fats more sustainably:
- Include nuts, seeds, and fish from sustainable sources. For help with picking fish, you can check out the Good Fish Guide.
- Look for oils, butter, and cheese from responsible producers — for example, farm shops or brands that buy directly from sustainable farmers. You can also choose certified organic or biodynamic products, or those involved in regenerative farming initiatives that care for the soil and replenish natural resources.
- When cooking, use only as much oil as you need to avoid waste.
Fats aren’t the enemy
Fats are an essential part of a healthy diet, but it’s all about choosing the right types and keeping portions sensible. Don’t get swept up by extreme diet trends or conflicting claims about “super oils” and miracle fats – even so-called “good fats” like olive or coconut oil can be overdone.. Instead, focus on a mix of healthy fats, like olive oil, nuts, seeds, avocado, and oily fish, and enjoy saturated or less healthy fats only occasionally.
Balance and moderation are what really count. Pay attention to your overall diet, listen to reliable guidance from nutrition experts, and remember that fats aren’t the enemy – they’re a key part of keeping your heart, brain, and body in top shape.
