When you walk into a supermarket, you are bombarded with products claiming to be ‘low fat’ ‘no fat’ ‘fat free’ or ‘less than 10% fat’, so it is no wonder that many people have a negative attitude to fat in their diet. Many weight loss diets promote very low fat eating patterns and we are constantly advised to steer clear of high fat foods. Is a low fat diet really the best way to lose weight, or do we need some fat in our diets?
The different types of fat
The answer depends very much on the type of fat. Saturated fats found in fatty meat, cakes, pastries, many commercial foods and other animal products such as cheese and full fat milk, can be detrimental to our health. This fat increases the unhealthy cholesterol, low density lipoproteins (LDL) and the total cholesterol in the blood, while lowering levels of healthy high density lipoproteins (HDLs); the type of cholesterol you want in your blood.
HDL cholesterol helps to remove the unhealthy fat from the blood stream, preventing the build up of blockages. A high intake of saturated fat in the diet has been linked to heart disease, some cancers, obesity, Type 2 Diabetes and a range of other conditions; therefore it is safe to say that a diet low in this type of fat is the way to go.
Similarly, a diet high in trans fats can also lead to negative health effects, much the same as those of saturated fats. Trans fats are found in many commercial food products such as cakes and biscuits and in some oil based spreads such as margarine, (although this is now tightly regulated, and most margarine now contain very little or no trans fats).
Fat contains the most calories per gram of all of the macronutrients, (carbs, protein, fatand alcohol), therefore it makes sense that reducing them will reduce our calorie intake and assist with weight loss. However, fats are not all bad news. In fact it is necessary to include some fats in your diet, or risk nutrient deficiencies and increase risk of conditions such as heart disease.
The fats that we should be including in our diets are the polyunsaturated and monounsaturated fatty acids (PUFAs and MUFAs). These types of fats are found in fish, nuts, vegetable oils, seeds and grains. A healthy diet should not contain more than 30% of calories from fat, but it is essential to include these healthy fats for the body to function correctly.
We need to consume unsaturated fats to provide essential fatty acids, such as Omega 3 and 6. These cannot be synthesised in the body, but are necessary for numerous processes and functions. Essential fatty acids play a key part in hormone production, cell membrane structure, and cell communication to name a few.
Why we need fat in our lives
1# For a strong immune system and inflammatory response
Diets low in unsaturated fats, in particular Omega 3s have been associated with reduced immune response. In animal models, essential fatty acids have even been found to reverse or significantly improve autoimmune diseases. It is also thought that Omega 3s may have anti-inflammatory effects and thus be beneficial for sufferers of conditions such as arthritis.
2# For correct function of the brain and nervous system
Fatty acids help to conduct electrical impulses in the nervous system, they are also the building blocks for cell membranes and hormones which regulate function of the nervous system. Omega 3 fatty acid, DHA, is important both for nervous system development in babies and in preventing deterioration of the nervous system in the elderly. It may delay development of conditions such as dementia and Alzheimer’s disease and improve cognitive function. Another essential fatty acid, EPA, when combined with DHA may provide benefits for conditions such as depression, bipolar disorder and ADHD.
3# To absorb fat soluble vitamins
The fat soluble vitamins A, E, K and D are absorbed by the body via chylomicrons, which are globules of fat. If your diet is low in fat over a long period, you are at risk of deficiencies of these vitamins, as they cannot be absorbed. These vitamins are essential for functions such as bone growth, blood cell development and clotting, healthy skin , eyes and reproduction. As well A and E being powerful antioxidants, fighting free radicals in the body.
4# To lower unhealthy blood cholesterol
Unsaturated fats such as omega 3 fatty acids have been shown to reduce levels of LDL cholesterol and increase good HDL cholesterol, as well as reducing the overall amount of fat in the blood. This protects against heart disease, and is also likely to reduce risk of other lifestyle diseases such as Type 2 Diabetes and stroke.
5# For healthy skin, hair, eyes and bones.
Due to their role in cell membranes, essential fatty acids play a part in keeping skin and hair healthy. Deficiencies of these fats may result in flaky itchy skin and dry brittle hair. It has also been found that women taking Omega 3 supplements experience less bone density loss over time, indicating a preventative effect in conditions such as osteoporosis.
Omega 3 fatty acids are also thought to have beneficial effects on many aspects of eye health. A diet high in this essential acid can help to protect against macular degeneration, decrease dryness and redness and improve production of tears.