Welcome to the second part of our nutrition series of posts. Our first piece talked about energy and calories and why food is so important in the first place, apart from just satisfying our taste buds! This week we’re putting the spotlight on dietary fats.
What is Fat good for?
Fat is often seen as the enemy when mentioned in the same conversation as dieting or weight loss. However, it is an essential part of the human diet, carrying out numerous functions in the body which include:
- Fuel - fats are the most concentrated form of dietary energy and provide fuel for cells
- Acting as a reserve supply of energy
- Forming brain tissue
- Insulation
- Transporting vitamins
- Organ protection
Types of fat
Fat consists of what are known as fatty acids and there are three types. Here’s the lowdown:
1. Saturated fatty acids (SFA), also referred to as ‘Saturates’
These are mainly found in the storage fats of animals and food derived from animals such as milk, butter, cream and cheese, especially hard cheese. Plant-based foods such as coconut oil and palm oil also contain high levels.Saturated fatty acids can increase the level of low-density lipoprotein (LDL) cholesterol - ‘bad’ cholesterol - which can lead to fatty deposits in artery walls, increasing the risk of cardiovascular disease.The term ‘Saturates’ appears on food labels as it is a health risk which people should be aware of. An adult's daily reference intake for saturates is 20g. If you see the colour red for saturates on a product label, it’s probably best to put it back on shelf and look for an healthier alternative!
2. Monounsaturated fatty acids (MUFA)
You should aim to swap saturated fats for monounsaturated fats as they are considered to be the healthiest type of fat. They protect the heart by lowering levels of bad cholesterol and maintaining levels of high-density lipoprotein (HDL) cholesterol - ‘good’ cholesterol. Good sources for monounsaturated fats are:
- olive oil and rapeseed oil - use these instead of butter when you can
- certain nuts such as peanuts, Brazil nuts and walnuts
- sesame, sunflower and pumpkin seeds - good alternatives if you have a nut allergy
3. Polyunsaturated fatty acids
These are divided into 2 types: Omega-3 and Omega-6. Humans do not make these types of fat in the body so we need to include them in our diet in small amounts.
Omega-3
Primarily found in oily fish such as sardines, mackerel, and salmon. Studies have found that eating oily fish can lower blood pressure and current government advice is to have at least two portions of oily fish a week. This includes canned fish like sardines, mackerel or salmon which can come skinless and boneless - simple to eat with salad or on toast.
Allergic to fish? Get omega-3 from nuts, seeds or vegetable oils such as rapeseed or linseed (also known as flaxseed) although they do not have quite the same effect as fish.There are also some other health benefits - research has shown that intake of omega-3 can increase blood flow by up to 36% during exercise, which can lead to better performance, and can decrease symptoms of rheumatoid arthritis.
Omega-6
Most of us get our intake from vegetable cooking oils such as sunflower, corn, canola and soya. It has been shown to lower bad cholesterol but excessive amounts can also lower good cholesterol so we shouldn’t consume too much.
Trans fats
Avoid!Trans fats are considered to be even more harmful than saturated fats because they raise bad cholesterol and lower good cholesterol. You should limit your intake of these fats as much as possible which means avoiding foods such as biscuits, cakes, pastries and some margarines. This type of fat is created in an industrial process which combines hydrogen with liquid vegetable oils to create a solid substance that is easy to spread and smoother in texture.The presence of trans fats must be declared on packaged food so if you ever see 'hydrogenated oil' or 'partially hydrogenated oil' in the ingredients list, it’s likely to contain trans fats. Fortunately, most UK supermarkets have removed hydrogenated vegetable oil from all of their own-brand products.
Daily Guidelines
As part of a healthy balanced diet, an adult's reference intake for total fat in a day is 70g, which is about one third of the total energy/calories we should consume.
Reducing fat intake
- Avoid processed convenience foods such as ready meals, pies and pastries, cakes, biscuits and crisps. It’s fine to have them as a treat - what’s important is that you don’t consume them on a regular basis, or several times a day!
- Choose low-fat versions of dairy products. They may not taste as good as full-fat versions but they won’t leave you feeling as heavy.
- Trim off fat and skin when cooking with meat. If you’re keeping the fat and skin for flavour, avoid adding cooking oil.
- Avoid glazing food with oil before cooking, use a light sauce or dressing to improve the taste later on.
- Consider meat alternatives such as Quorn, falafel or tofu as the saturated fat content is lower.
What do you do to reduce your fat intake? Share your comments below or on Facebook or Twitter.Next in the series: Carbohydrates
References
- Happy Happy Vegan - Vegan fat sources
- Fat: the facts - NHS Choices
- Reference intakes on food labels explained - NHS Choices
- A fat lot of good fat - BBC Good Food
- Omega-3 - The Association of UK Dietitians
- Speeding Recovery - Nutrition and Supplementation for Exercise - Today’s Dietitian
- Diet Specialist
- Main image by Ramon Gonzalez
- Article image by Robert Owen-Wahl