As more fat substitutes appear on the market, new reports abound on the importance of fat in our diet. The fact is, both can play their own role - it's all a question of balance. Aquarius reports.
We have become a nation of fat phobics, scared of having that dab of butter on our toast or a fat-laden croissant. But, as a recent report has proved, cutting out the fat from our diet can be as harmful as having too much.
The Institute of Medicine, USA, has recently raised the recommended fat intake from 30 per cent or less to 20 to 35 per cent of your total calorie intake. But before you reach for the double cream to put on your apple pie, there is a catch - well two, really.
Firstly, saturated fats in foods such as full-fat dairy products, red meat and pastries, should still be kept to a minimum. The recommended amount of daily exercise has also been raised from from 30 to 60 minutes in an effort to cut down on obesity.
Balance is the key issue that comes out of the report. What has been happening in the US is that people have been filling up on low-fat or fat free foods high in carbohydrates, which has been found to reduce the good cholesterol in the body. Good cholesterol or High Density Lipoproteins (HDLs) are necessary to help reduce the likelihood of a heart attack. On the other hand, diets high in saturated fats raise the level of ‘bad' cholesterol or Low Density Lipoproteins (LDLs).
So where does this leave all of us in the fat war? Here's a quick guide to the most commonly asked questions.
1 Why aren't all fats equal?
Fats and oils are made up of molecules of fatty acids combined with a substance called glycerol. All fatty acids contain carbon, oxygen and varying amounts of hydrogen. It is the level of hydrogen which determines whether fat is richer in saturated fatty acids, mono unsaturates or polyunsaturates. Every fat contains all three types of fat but in varying proportions.
2 Aren't saturated fats complete dietary no-nos?
Saturated fats are the worst of the three types of fats and should be kept to a minimum. These are fatty acids that are ‘saturated' with hydrogen; they are solid at room temperature and can be found in dairy foods, cakes and biscuits. Coconut and palm oil are the only vegetable oils that contain lots of saturates.
A high intake of saturated fat contributes to increased levels of cholesterol in the blood, which can clog the arteries and slow the passage of blood and nutrients through the system.
3 Should I be choosing polyunsaturated fat?
Polyunsaturated fats are found in plant foods such as nuts, seeds and vegetable oils including soya, sesame, canola, safflower and sunflower.
On the good side, polyunsaturates play a very important role in maintaining the strength and stability of cell membranes as they are a vital source of essential fatty acids.
Liquid at room temperature, the downside of polyunsaturated fats is their vulnerability to oxygen attack. Whereas saturated fats tend to be solid, stable and slow to decay, polyunsaturates are much quicker to oxidise and turn rancid. This can destroy vital nutrients within the oil such as vitamin E and essential fatty acids. This oxidisation process is also now thought to lie behind problems such as furring of the arteries, diabetes, cataracts and ageing.
Choose unrefined, cold-pressed oils and keep them in the fridge to protect against rancidity. Get your polyunsaturated fats from foods rich in these oils, such as nuts, seeds and oily fish.
What about olive oil?
Monounstaurated fat gets a resounding thumbs up when it comes to your diet. Found primarily in olive oil, rapeseed oil, olives and avocados, it is more stable than polyunsaturates. Olive oil not only lowers the level of ‘bad' cholesterol in the body, it maintains high levels of ‘good' cholesterol to maintain a healthy heart and helps to balance blood glucose.
Monounsaturates can also benefit the whole system by keeping the blood flowing freely. Research in the UK discovered that a fatty acid found in olive oil discouraged the blood platelets from clumping together, thereby reducing the possibility of blood clots and strokes.
The oil is also thought to have a positive effect on lowering blood pressure by making the blood vessel walls more elastic, causing them to expand, thus easing circulation.
Olive oil contains vitamin E and natural antioxidants which can help fight off free radical damaged cells in the body which can cause furring of the arteries, put a strain on the immune system and have the potential to cause cancer.
4 So, why are low fat diets harmful to our health?
Extremely low-fat diets - under 15 per cent of total calories - have been linked to a number of illnesses, including a suppressed immune system, decreased endurance and muscle strength, vitamin deficiencies, hair loss and skin conditions such as eczema and psoriasis.
In a study at the State University of New York, subjects on a low-fat diet manifested calcium, magnesium, zinc and vitamin E deficiencies. When the same subjects boosted their fat intake, their vitamin and mineral levels increased while their heart rates, body fat and cholesterol levels stayed the same.
Nadine Chelmiah, nutrition and fitness consultant at the Emirates Aviation College, explains: “Fats keep us warm, make food palatable, carry the essential vitamins A, D, E and K around the body and provide essential fatty acids that you can't produce in your body but are needed for the function of every living cell. They are vital for regulating hormone balance and immune function, a healthy nervous system and the arteries. When you are on a low fat regime, your system is deprived of these vital nutrients and you may suffer from dry, flaky skin, brittle nails, extreme coldness of the hands and feet, difficult periods, pre-menstrual syndrome and breast pain.”
The two families of essential fatty acids (EFAs) - omega 3 and omega 6 fatty acids - are primarily found in polyunsaturated fats and are necessary to produce other EFAs. Omega 6 is generally easily obtained from the diet through grains, vegetables and ironically, processed foods.
It is omega 3 which is leading the way when it comes to healthy fats. Found in oily fish such as salmon and mackerel, other sources include flaxseed or linseed oil, and evening primrose or borage oil.
Omega 3 has been found to protect against heart disease and is vital for brain development and immunity, which is why breastfeeding is so important as breast milk naturally contains EFAs from the mother. In fact, manufacturers are now adding EFAs to both formula milk and dairy milk.
Another advantage of the Omega 3 and 6 fatty acids (together with omega 9 from monounsaturated fats) is their ability to burn fat. Says Nadine: “If one of these is missing or not available in adequate quantities, the process of burning fat cannot be carried out efficiently. So, while you are saying no to fat, you may actually be saying yes because the burning process has slowed down.”
5 How much fat is okay?
With the new recommendations from The Institute of Medicine, up to a maximum of 75g is okay for women and 100g for men. Of this, a maximum of one-third should come from saturated fats, the remainder from monounsaturates and polyunsaturates. Watch out for ‘hidden' saturated fats in fast foods, pies, pastries, meats and biscuits.
And remember, if you are trying to lose weight, whichever type of fat you choose, they all contain nine calories a gram, that's double that of protein or carbohydrates.
For general cooking, olive, soya, rapeseed, safflower or sunflower and canola are best; eating a little butter as part of a healthy diet is unlikely to cause you much harm. If you like having a lot of yellow spread on your bread, choose a low fat spread, which has less than 15 per cent saturates.
6 I've heard that margarine is as unhealthy as butter. Is that true?
This is really the biggest area of confusion. It wasn't long ago that we all eschewed butter over ‘healthier' margarines. But evidence then emerged that these new ‘saviours' may be just as bad for us as butter. This is because the oils from which margarines are made must be hydrogenated to make them solid at room temperature.
This process - which involves adding hydrogen to a fatty acid - creates trans-fats, which react in the body in much the same way as saturates. Nearly all spreadable fats contain hydrogenated fat; soft margarine may have as little as five per cent and hard as much as 40 per cent. Also, look out for words such as ‘partially hydrogenated vegetable oils' on packets of biscuits and processed foods as these will contain trans-fats.
Says Nadine: “Butter is more visible and a mere dab may satisfy you; a ‘healthy' soft margarine, however, will encourage you to spread it on by the tablespoon. In the long-run that could mean both greater trans-fats and calories.
“The ideal alternative is a dribble of olive oil mixed with herbs. If you do prefer margarine, go for the softer, olive oil based ones and absolutely avoid the stick hard varieties.”
7 Is it okay to eat foods using fat substitutes?
Olestra, the first non-caloric fat substitute, has been approved by the Food and Drug Administration, USA, for use in commercially prepared savoury snacks such as potato chips, cheese puffs, crackers and popcorn. Every such product is labelled Olean.
Olestra is basically made of table sugar and vegetable oil but because the molecules are larger than those in ordinary fats, it's not digested or absorbed by the body. The obvious benefit of olestra is that you can eat foods traditionally high in fat without the worry.
There are two main concerns regarding Olestra: firstly, it may cause stomach upsets and people with sensitive stomachs are recommended to limit their consumption of the product.
The second concern is that since the fat passes out of the body, certain fat-soluble vitamins - such as A, D, E and K - pass along with it. n
|Easy ways to cut fat intake
Eat more fresh fish and free range poultry (skin removed); cut down on red meat particularly beef burgers, sausages and bacon.
When eating out stick to red sauces rather than white, rich in saturated fats. Order salads with dressings on the side, so you can control how much you eat.
Enjoy sticky buns, cakes, biscuits, chocolate, ice cream and crisps as an occasional treat.
Stir-fry, grill, bake or poach your food. Avoid deep-fried foods.
Hidden Fats in Take Away Foods
|Fish & Chips||48g||15g|
|KFC chicken & chips||47g||18g|
|Big Mac & chips||43g||19g|
|4 slice Pizza supreme||40g||16g|
|Nuggets & chips||35g||15g|
|Chinese veggies (500g)||30g||6g|
Ready Reckoner for fats in oils