Fats and Oils
Fats and Oils: Your questions answered
Excerpts from Nicole Senior article in the Healthy Food Guide
Fat is one of the most talked-about nutrients but one of the most
misunderstood. Here are some answers to the most commonly asked
questions.
1. What are fats?
Fat is one of the major nutrients found in food - called
a macronutrient. Protein and carbohydrate are also called
macronutrients. Fats are chemically similar substances composed of
fatty acids. They include liquid fats (oils) such as olive and
sunflower oils; as well as solid fats such as butter,
vegetable shortening, ghee and lard.
2. Is a fat-free diet healthy?
No! You need fatty acids to build and maintain cell
membranes and to make certain hormones. That's why some fatty
acids are called essential fatty acids. It's necessary to include
some fat in your diet to ensure you get these essential fatty
acids, along with the fat-soluble vitamins A,D,E and K. Fats are
also a concentrated form of energy, which is important for growth.
So fats are essential, but it's important to choose the right type
of fat.
3. How did fat get such a bad reputation?
Saturated fat is the main culprit in raising cholesterol
levels and heart disease rates. However, there are other types of
fats which are essential for good health.
4. Which fats are the good ones?
Fats are classified as saturated or unsaturated,
depending on their chemical structure. Unsaturated (good) fats
include polyunsaturated and monounsaturated types, which are better
for you because they help maintain healthy cholesterol levels
and heart health. Polyunsaturated 'good' oils include
sunflower, soy bean, walnut and sesame oils. Monounsaturated 'good'
oils include avocado, canola, olive, macadamia, rice bran and
peanut oils.
5. Why do I love fatty foods so much?
Humans are driven by a powerful survival instinct based
on a 'feast or famine' environment; we're programmed to eat
high-energy foods so should food become scarce, we'll have a better
chance of surviving. We also tend to eat more fat than is good for
us because most of us are used to the flavour of fat. It also gives
foods such as biscuits, pastry and deep-fried fish'n'chips a
pleasant crunchy texture. Food manufacturers also often add fats to
many foods to improve flavour and texture, so we may be eating more
fat than we realise.
6. Which fats should I be eating less?
Saturated fats are found in fatty meat, butter, cream,
full-fat milk and dairy foods, processed foods containing palm oil,
and many deep-fried takeaway foods. Chocolate and coconut products
like Kremelta and coconut cream are also rich in saturated
fat.
7. Which is healthier: butter or margarine?
Table margarine (Oil spread), is recommended as a
healthier choice than butter by the NZ Heart Foundation. It's
better because it's made with healthy oils which contains much less
saturated fat than butter. Contrary to popular belief, oil spreads
are not a major source of trans fats. Check the nutrition
information panel and choose spreads with less than 15g saturated
fat per 100g.
8. How much fat should we eat?
Between 30-35% of our daily kilojoule intake from fat is
usual. In a typical diet of 8700kJ, this is between 50-80g fat each
day. Fat is already present in some foods, so a healthy amount to
use is between 1ý-2ý tablespoons of healthy oils and
oil spreads a day. Saturated fat should make up no more than about
30g in a typical diet.
9. Which is the best oil to use?
Any oil made from vegetables, seeds or fruits is good
(see question 4). Coconut and palm oils are the exceptions to this
rule - avoid them as they are high in saturated fat.
10. Can I cook with extra-virgin olive oil?
Yes. But other oils, such as rice bran oil, have a higher
smoke point, which means these oils tolerate high temperatures
better than extra-virgin olive oil. Extra-virgin olive oil also
costs more.
11. How will I know if oil has gone off?
Oil that has oxidised, or gone rancid, has a
characteristic stale, musty smell. Don't use rancid oil. Healthier
oils go rancid more easily than unhealthy ones, so use them quickly
and store them correctly.
12. How much salad dressing and mayonnaise can I
use?
Mayonnaise and salad dressings are usually made with
healthy oils but commercial ones can be quite salty. It's best to
make your own mayonnaise and use it in moderation.
13. What are omega-3 fatty acids?
Omega-3 fatty acids are essential polyunsaturated fatty
acids.
Why we need them: Our bodies can't make them so we need to
get them from our diet. Omega-3 refers to both short-chain fatty
acids (plant foods) and long-chain fatty acids (animal foods). It's
best to eat a mix of both.
Where to find them: Plant foods such as canola and soy
bean oils, flaxseeds and walnuts are the best sources of omega-3
short-chain fatty acids. The richest source of long-chain fatty
acids is oily seafood (especially mackerel, sardines and salmon),
eggs, brains, liver, kidneys, and lean red meat.
What they do: Omega-3 fats, and especially the long-chain
fats, are linked to better heart and mental health, a reduced risk
of inflammatory diseases, and brain development in children.
