Diet and nutrition

Joseph Hogan, physiologist at AXA Health

Good fats and bad fats

Diet and Nutrition

7 May 2019

Fats are an essential part of our diet. However, different types of fats have very different nutritional value - not all fats are born equal. Some fats are better for us than others and despite the fact they may have become ‘Public Enemy Number One’, with many people fearing them, not all fats are bad fats. Provided you make the right choices when it comes to eating fats, they shouldn’t be avoided in our diets – the right ones are essential for keeping us healthy.

Joseph Hogan, physiologist at AXA Health emphasises that we should not be cutting out all fats. Not only would this be extremely difficult and limiting for our diets, fat is one of three macronutrients that are essential for a balanced diet. It is needed for the absorption of some vitamins and essential nutrients, such as omega-3 & omega-6 fatty acids. Fats are a fundamental component of our diets, but the quantity and quality of the fats we eat is something that we should consider.

What should I be aiming for?

All fats, no matter which foods they come from, are equally high in calories (9 calories per gram). Therefore, when trying to lose or maintain weight, we need to be cautious of the fats we’re consuming. However, it’s the varying cholesterol levels they each contain that is part of what differentiates types of fat and their effect on our bodies.

Cholesterol is made by the liver and is how we transport fat around our body. It contributes to the production of hormones and fat-soluble vitamins, and to the creation of bile acid to aid digestion. It is carried in the blood as either low-density lipoprotein (LDL) or high-density lipoprotein (HDL). Both play different roles in the body but, in general, HDL will collect up fats from areas of the body where we are holding too much and transport it to the liver to be removed, whereas LDL will transport fats from the liver to our bodies’ tissues.

While both roles are needed by the body, having too much LDL will increase our bodies’ retention of fats and can lead to negative health consequences, such as a build up of fats around our vital organs as well as in our arteries, leading to vessel damage and even a stroke. Some sources of fats are more prone to becoming LDL when ingested into our bodies and these are typically those we call saturated and trans fats.

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.

Which fats are the best good fats?

For many years we’ve been told that a Mediterranean diet is the way to go, and there are good biological reasons for encouraging this. Eating more unsaturated, as opposed to saturated fats, aka the ‘bad’, fats can lower the LDL cholesterol levels in our blood.

There are four main categories of fats that you’ll see listed on food packaging labels. If you’re looking to boost your level of unsaturated fat, which foods should you be aiming for?

The helpful chart below outlines what you should be reaching for, and what you should be cautious about consuming too much of:

good fats bad fats

Joseph has some top tips for being smart with your fat intake:

  • Swap out saturated fats for small amounts of monounsaturated fats and polyunsaturated fats, where possible. For example, try swapping a beef curry for salmon satay.

  • Reduce consumption of red meat and trim off excess fat from meats, as well as removing the skin from poultry.

  • Measure out oil when frying, try using a teaspoon or use a spray oil to control the amount you use.

  • When cooking at home, try to grill, bake, steam, boil or poach your foods to avoid adding extra fat.

  • Swap whole milk for semi skimmed milk or plant-based alternatives, though be wary of added sugar and lower protein in some of these alternatives.

  • 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.

There are some foods, which though on the surface may seem like a good option, are not necessarily the best for choosing the right fat intake. Some popular ones to look out for include:

Breakfast muffins: although super tasty and containing fruit, muffins can be high both in sugar and fats. Consider swapping the muffin for porridge but keeping the blueberries, as these are a great source of vitamins and one of your five a day.

Yoghurt coated raisins: now these little white nuggets taste amazing but can contain almost double the calories of plain raisins. Not only does the yoghurt add calories, it also contains fat and sugar, so it’s best to try and stick with plain, dried fruit.

Coleslaw: Full of veg and healthy, right? Maybe not, most coleslaws are dressed in mayonnaise which is both high in calories and fat. Consider low fat options or, better still, make your own. You can choose the veg that goes in and make a low-fat yoghurt dressing to cover it. Try adding in a few fennel seeds and a splash of lemon juice.

Granola: Many granolas can pack a large number of calories; around 180 kcal and 8.2g fat in a small portion, in fact. Add to this a serving of whole milk and it can add up to around 275 kcal and 13g of fat. However, swap this for muesli and semi-skimmed milk and you could save around half the fat. You could also consider adding in some fruit as one of your five a day.

Cereal bars: These are normally stuck together with fats and sugar, like glucose and vegetable oils, which can turn a healthy sounding snack into a fat packed treat. Always check the packets carefully before reaching for that on-the-go bar.

On the other hand, there are some foods which though labelled as high in ‘fat’, are actually crammed full of all the healthy fats we need, so shouldn’t be avoided! Some of these common misconceptions include:

Oily fish, like mackerel and salmon: Although oily fish may seem high in fat, this is not a reason to avoid them. In fact, it’s recommended that we consume at least one portion of oily fish a week as they contain a large amount of omega-3 fats, which are essential fatty acids that we need in our diet, as our bodies cannot produce them naturally. Although white fish do contain some of these nutrients, they are in much lower levels than in oily fish.

Yoghurt: Some yoghurts are low in fat; however, others can contain up to six times the amount of fat than their low-fat counterparts. Always check the nutritional information and be wary of creamier Greek-style varieties. Another thing to bear in mind is that many manufacturers add sugar to their yoghurt, even the plain varieties, so always check for this on the label too.

Avocado: As a vegetable, it must be low in fat? Not quite, avocados are naturally high in fats; however, they contain less saturated fat than foods like cheese since they are packed with HDL-boosting fats. They are high in calories but can be enjoyed as part of a balanced diet, with half of an avocado counting as one of your five a day.

Fat from our food is essential to keep our bodies functioning well. The quality and quantity of the fats we consumer is crucial as too much can add unneeded calories to our diets and increase our levels of LDL cholesterol. While some food sources contain large quantities of fats that are readily turned into LDL cholesterol, others are high in fats that give us HDL cholesterol and are vital to our health.

Ultimately, as Joseph says, fat is an essential part of our diet. Rather than thinking of it as the enemy, look to improve the types of fats you’re eating. Replace saturated or trans fats with unsaturated fats, reduce those you use in cooking and you’ll be on your way to keeping fats a healthy, necessary part of your diet.


Fats explained - British Heart Foundation
Fats in your diet - British Heart Foundation
Different fats - NHS website
The eatwell guide - NHS website

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