Older couple eating healthy lunch together

Lucy Morgan, dietitian at AXA Health

Fat versus fiction

Diet and Nutrition

20 September 2023

There are many misconceptions and myths about fat. For years, fad diets, advertising and general health warnings painted it as the enemy. We were told that fat could lead to weight gain, heart disease and many other health issues.

But the truth about fat is a lot more complex. There are different types of fat and, while some of them are bad for us, others are good. And some are essential.

So, when it comes to making healthy choices, managing your health and eating well, it’s important to understand the truth about fats. Lucy Morgan, dietitian at AXA Health, helps clear things up and separates the myths from the facts to help you on the road to better health.

So, what’s the truth?

Firstly, fat shouldn’t be avoided. It’s an essential part of a healthy, balanced diet. Fat is one of the three macronutrients that are essential for a balanced diet – the other two are protein and carbohydrates. Our bodies need fat for the absorption of certain vitamins and provide essential fatty acids: omega-3 and omega-6.

So, fats are a fundamental component of our diets. But, as we’ve mentioned, there are different types of fat. And, while they’re all high in energy and have an identical calorie value of nine kcal per gram,1 not all fats are created equal.

What are the different kinds of fat?

There are unsaturated fats, saturated fats and trans fats. As a very general rule, you should avoid trans fats, limit saturated fats and aim to eat unsaturated fats, which are considered more beneficial to your health.

Unsaturated fats can improve your blood cholesterol levels, ease inflammation and regulate heart rhythms.

There are four main categories of fats that you’ll see listed on food packaging labels:

Polyunsaturated fats are unsaturated fats that can reduce blood cholesterol. The two main kinds of polyunsaturated fats are omega-3 and omega-6 and they can be found in foods like:

  • corn and sunflower oils,
  • walnuts,
  • fish
  • and flax seeds.

Monounsaturated fats are unsaturated fats that can protect your heart, maintain good HDL cholesterol levels and reduce bad LDL cholesterol levels. They’re commonly found in:

  • olive oil,
  • peanut oil,
  • avocados,
  • and various nuts and seeds including almonds, hazelnuts, pecans, pumpkin seeds and sesame seeds.

Trans fat is the more common name for trans fatty acids. Trans fats occur when liquid oils are heated and transformed into solid fats during a process called hydrogenation.

They’re seen as the worst type of fat for the heart and body because they raise bad cholesterol levels, cause inflammation and can increase the risk of heart disease. They’re most common in foods that list hydrogenated (or ‘partially hydrogenated’) oils or fats in their ingredients, but very small amounts also occur naturally in dairy products and meat.

Although this type of fat is strongly linked with heart disease, people in the UK do not typically consume much of these, as manufacturers often remove this type of fat from food products.

Saturated fats are thought to produce bad LDL cholesterol in the body and increase overall cholesterol levels. It’s most commonly found in:

  • fast food,
  • full fat dairy including butter and cheese,
  • beef,
  • sausages
  • and bacon.

Saturated fat is often present in healthy foods, but in much smaller quantities, so while it may not be possible to cut it out of your diet, cutting down on saturated fat will ultimately be beneficial to your health.2

What are the most common myths about fat?

We shouldn’t eat fat

If you take nothing else away from this article, remember one thing: your body needs fat. More accurately, it needs good, unsaturated fats.

Firstly, fat supplies energy to your body in the same way that protein and carbohydrates do. Gram for gram, it’s actually higher in calories, so when consumed sensibly it can be a great source of energy.

There is fat throughout your body. It’s part of every cell and makes up around 60% of your brain.3 We rely on fat to absorb nutrients and vitamins, as well as to provide essential fatty acids that we can’t produce ourselves.

Fat also plays a part in insulin production, immune function and regulating various hormones. So…your body needs fat. It just needs the right kinds of fat.

Fat causes weight gain

This is a common myth as people (understandably) assume that dietary fat will automatically turn into body fat. But this isn’t the case. As mentioned previously, all fats contain the same nine calories per gram, so while they can contribute to weight gain through their calories, fats won’t automatically cause weight gain when eaten in moderation.

Currently, men are recommended to consume no more than 30g of fat a day and women to consume no more than 20g. It’s also suggested that we try to swap out saturated fats for unsaturated fats in our everyday lives where possible.4

Fat raises cholesterol

Just as there are good and bad fats, there are also good and bad types of cholesterol. And, as we’ve touched upon already, different fats can affect the two types of cholesterol in different ways.

Bad cholesterol, or LDL, increases the risk of heart disease and stroke. Both monounsaturated and polyunsaturated fats actually help to reduce LDL cholesterol levels. They can also help increase your levels of good cholesterol (HDL), which helps lower the risk of heart disease.

On the other hand, trans fats do raise your LDL cholesterol levels, so should be avoided. And, while it’s not entirely clear whether certain sources of saturated fats increase cholesterol levels or not, it’s still recommended to limit the amount you consume.

To learn more about cholesterol, read our article: What is cholesterol and how can you reduce it?

What should I be eating?

As mentioned, try and incorporate monounsaturated fats and polyunsaturated fats into your diet. Avoid trans fats wherever possible and just be aware of your saturated fat intake.

Eating more unsaturated fats instead of trans or saturated ‘bad’ fats can help lower the LDL cholesterol levels in your blood. It’ll also help regulate your immune system, hormone levels and your body’s absorption of essential nutrients and vitamins.

Here are some top tips for being smart with your fat intake:

  • Swap ingredients that are high in saturated fat for a healthier, unsaturated alternative. For example, try swapping out the beef or lamb in a curry for fish, chicken or tofu.
  • Trim off excess fat from your meat and remove the skin from poultry.
  • When cooking at home, try to grill, bake, steam, boil or poach your foods as much as possible to avoid cooking with oil and adding extra fat.
  • If you are using the frying pan, measure out your oil. Try using a teaspoon or an oil spray to control the amount you use.
  • Swap whole milk for semi-skimmed or plant-based milk options, though be wary of added sugar and lower protein in some of these alternatives. If you choose to go for plant-based milk, do make sure it is fortified with calcium.
  • If eating cheese, consider cottage cheese, ricotta and some soft cheeses, which are lower in fat than hard cheeses like cheddar. Always be wary of portion size and grate hard cheese, if possible, to make it go further.
  • Reduce your consumption of red meat.

Fat is essential in keeping your body functioning well. So, rather than thinking of it as the enemy, try and incorporate healthy fats into a balanced diet and think of them as an important, necessary part of your diet.

The quality and quantity of the fats you consume play a vital role in your overall health, so it’s important to understand it properly and make healthy choices. We’ve put together a list of some useful resources to help you discover more.


  1. The truth about fat - British Heart Foundation
  2. Types of fat - Harvard School of Public Health
  3. Debunking myths about fat - Johns Hopkins
  4. Fats explained - British Heart Foundation

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