Fat doesn’t HAVE to be the ‘F’ word! Fats are essential to our health. We need fat both in our daily diet and as part of our body composition.
What they are:
Fats can be categorised into saturated and unsaturated, depending on its chemical structure. An easy rule of thumb to know which is which is: Animal fat is generally saturated and solid at room temperature, e.g. lard, butter etc. and plant fat is unsaturated and liquid at room temperature, e.g. sunflower oil, olive oil etc. There are some exceptions to the rule, such as coconut oil, but this is the easy way to remember
Why do we need them?
Fats are an incredibly important macronutrient and play a critical role in our overall health. They make up the structure of membranes around the cells, transport fat-soluble vitamins A, D, E and K and are an important precursor of hormones. Fat fuels certain organs such as our hearts and are an abundant source of energy.
How much energy do they yield?
Fats are the densest source of dietary energy, providing 9kcal/g and this fuel will be used in conjunction with carbohydrate during long, endurance exercise, such as marathons.
How much do we need?
Our daily fat intake should be about 20%-30% of our daily calories, approximately, and from mainly unsaturated fat.
Some more information:
There are good fats and bad fats. Generally speaking, unsaturated fats such as olive oil, flax oil, avocados, nuts and seed oils are considered healthy fats and saturated fats should be limited as they are implicated in causing cardiovascular issues.
There are also trans or hydrogenated fats, which are man-made fats, and are created when food manufacturers add hydrogen, a process called hydrogenation, to unsaturated fat to change its chemical structure. This was done to plant oils such as sunflower oil to solidify it and to use it as a spread. It has been found that trans-fats from hydrogenated oils have harmful effects on blood lipids, promote inflammation, and cause blood-vessel abnormalities, all of which are risk factors for heart disease. A Harvard Medical School research study stated that removing trans-fats from food would save tens of thousands of lives every year. These fats have been banned by governments around the world.
Just as saturated and trans-fats can cause heart disease, there is a group of fatty acids that can actually prevent it – they are Omega 3, fatty acids, in particular EPA and DHA. They have a positive effect on the health of your blood as they lower bad cholesterol and can prevent unnecessary arterial clotting, (stroke and heart attack). There have also been studies to suggest that a diet rich in these polyunsaturated fats can improve learning abilities and cognitive function and relieve depression. Fatigue, itchy dry skin and brittle hair and nails can also benefit from these fatty acids. Good sources of these are oily fish, such as trout, mackerel, salmon, tuna (avoid shark, marlin, swordfish etc. because of Mercury contamination) Linseeds, Walnuts, Flax oil etc. An intake of about 1.1gms for women and 1.6gms for men per day of these oils is adequate, which would be provided by 2 servings of oily fish per week.
Saturated fats are found in meat and meat products, processed foods, such as crisps, pizza and deep fried foods, and should be avoided when possible.