all cooking oils the same, or are some preferred for different kitchen
tasks, like frying? And is frying healthy?
Gustavo Bizon, Buenos Aires, Argentina
Most of us will, from time to time, eat deep-fried foods. We've
all heard that too many fried things are not good for our health,
and nutritionists warn us that only 10% of our calorie intake should
come from fats.
At my cooking classes I usually include a few deep-fried dishes
to highlight the versatility of a vegetarian diet. Apart from the
question of calories, the two most common questions that I am asked
about frying are these: Is frying in oil bad for the health, and
do foods cooked in it have a bad effect on the organs?
I explain that all deep-frying is not equal, and that there are
three factors to consider when answering these questions - (1) the
type and characteristics of the oil used,
(2) the temperature, and (3) the time factor.
(1) The type and characteristics of the oil
- Peanut oil is good if you want to fry every day with the same
oil, but only if you want to use it a few hours per day. Peanut
oil can be strongly contaminated with aflotoxins, cancer-producing
by-products of mold fungi.
- Sunflower oil is good if you fry the whole day continuously
with the same oil. But then it should be replaced.
- Coconut fat is good for frying if it is not hardened. Hardened
fats and oils are extremely dangerous to the health and should
- Ghee or clarified butter is good for frying, but it is not commonly
used in the food industry because it is more expensive than plant
oils. It is highly recommended in India's classic Ayur Veda. Click
here for more on ghee.
The main thing to remember is that none of these frying oils should
ever be allowed to smoke. If this happens, the oil should be replaced
with fresh oil. The reason for this is explained as follows.
(2) The temperature
There is a smoking point for every type of oil. For most frying
oils, this temperature is around 180 - 190 degrees C. Shortly before
smoking point, the oil starts to decompose, and the formation of
free radicals and metabolites takes place. These substances are
highly toxic and have been definitely linked with cancer. Further,
this oil is cannot be properly digested by the liver and will lead
to liver problems and a reduction of digestive ability if consumed
Some oils should never be heated at all, like oils containing polyunsaturated
fatty acids. This also includes most cold-pressed, unrefined oils,
safflower oil, nut oils, wheat germ oil, and linseed oil. Olive
oil contains mainly mono-unsaturated fatty acids and it performs
better if used for pan-frying rather than deep-frying.
Experienced cooks should be able to keep the temperature of oil
at a constant level. If you are having difficulties in this regard,
invest in a cooking thermometer, or use a deep-frying device with
(2) The time factor
The hotter an oil gets, the faster oxidation and decomposition
takes place. And the longer you use an oil the more it oxidizes.
Between two frying sessions, oils should be stored cool and light
protected to slow down oxidation. If food particles remain in the
oil during frying, they tend to burn and cause a rapid deterioration
of the oil.
Test strips to measure oxidation are available at well-stocked
kitchen suppliers. Keep all these points in mind for healthy, trouble-free
Previous Answer >>