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Over cooking, microwaving, re-heating and re-frying destroys essential nutrients

September 19, 2006


We all eat burgers and fries, pakodas (stuffed and fried lentil dish) and pav-bhaji (white bread with over-cooked, mashed and fried vegetables) , even if it’s with a tinge of guilt. What we really look forward to is that home-cooked meal of steaming rotis, sabji and dal chawal…because we know that home food is good food.

Or is it? We’ve got to admit that we aren’t eating like our ancestors did…straight from the field and cooking our produce just a little, if at all. And to add to our woes, we pressure-cook, microwave, deep-fry, re-heat and re-fry, all which can ruin our food. Today, it’s the taste that matters, nutritive values can go jump. Well, that’s all very fine…until the health problems start. “It can take as early as six months for the effects of a nutritive deficient diet to show,” says dietician Rammi Kothari.

Most vitamins are unstable
Many of the nutrients in vegetables are so unstable that they start to deteriorate immediately after the vegetables are picked. “Vitamin C and some of the B vitamins are destroyed by exposure to light, air and heat. They are also liable to dissolve in water,” says nutritionist Niti Desai.
Using vegetables that are already a few days old, peeling, chopping and leaving them exposed to the air or soaking in water is like sounding the death knell for vitamins. If any nutrients do survive, over-cooking or throwing away the cooking water will finish them off. And if you add baking soda to keep your veggies green,this ensures that vitamins like B1, B2 and B5 make an even speedier exit.
The bad news is that it’s not only the B and C, which go down the drain, it’s also others like A, E and beta-carotene (an oxidant). “High temperatures produced during deep-frying can destroy fat-soluble vitamins like A,” confirms Kothari. Vitamin E is even more heat-sensitive than A and also suffers in the deep freeze. It’s loss is worrying because it is present in miniscule quantities in our food anyway.

Minerals can get washed away too
Minerals are not indestructible either although they do stand up to heat. Water is their worst enemy as they dissolve easily. If you throw away the water before or after cooking and wash grains and pulses too well – you lose them. “Rice and pulses should be washed just once unless you think they contain insecticide,” says Leena Martin, dietician, Holy Family Hospital.

Protein is tougher to destroy
Protein has a life as well, though admittedly it takes a lot of over-cooking to destroy it’s nutritional value. The hard lacy edges of a fried egg don’t get you anything. While the right amount of cooking makes protein easier to digest, over-cooking does just the opposite. “Protein can become indigestible with overcooking,” says Martin.

Fatty acids are sensitive to heat too
Some fatty acids, sometimes referred to as vitamin F, are also damaged by cooking, and exposure to light and air.
What’s worse is that when oils are heated to very high temperatures as during frying, the fatty acids can convert to carcinogenic substances. “Oil should not reach smoking point as it produces compounds which are dangerous to health,” warns Desai. Sometimes one can smell the rancidity that has been produced in the stale oil. If you simply must re-use oil, make sure that you don’t heat it unnecessarily. After the first use, cool it immediately and strain through a fine mesh and store in the refrigerator. Don’t use repeatedly as subjecting it to prolonged heat in this way causes it to spoil.

Make it the natural way
If home food is to score above fast food, it’s important that we don’t cook the way hotels do. By re-heating, re-frying…storing, freezing. At least not all the time.
If you do eat like this and your body seems to be taking it – it’s probably because you are young and healthy. “Young healthy individuals with a high metabolism rate take longer to show the ill-effects of a nutrient deficient diet,” explains Kothari.
However, finally everyone has to pay the price of a bad diet.
People may not even relate the problems they are suffering from to their diet. It’s the little things…skin problems, lowered immunity or simply fatigue. But then this is only the beginning…poor nutrition makes one susceptible to many diseases ranging from heart disease, diabetes to cancer.

(Published in the Times of India in 2005)

Related Reading: Moody food – how food can cause depression, nervousness, anxiety and irritability
Chemicals in our everyday food,
Watch your food packaging,
Maggi- is it healthy?
Eleven reasons why Indians are not healthy
Leading a normal life with diabetes
Why youngsters die of heart attacks

9 Comments leave one →
  1. December 21, 2006 12:27 am

    Hi, I came across your site as I was searching for some info on vegetable nutrients. Can I reference this post in my blog and then you provide a trackback to mine? I haven’t published my post yet… just want to see if you are OK to provide the trackback.

  2. Neera permalink
    May 8, 2007 1:59 am

    Hi Nita

    It was by chance that I came accross your blog when I was searching for some health and nutrition related information, specifically related to desi ghee. I see a mention in here that there is a strong belief among Indians that desi ghee is very good. Could you please share more information with me? From what I understand after having gone through some articles on nutrition is that fats that solidify at room temp(which desi ghee does) are saturated fats. Would appreciate if you could enlighten me further.
    Incidentally, I am glad to have stumbled upon your blog and shall read it more in detail. I too like to write about parenting (I read that you did that when your daughters were little). Do visit my blog I am not sure whether you are going to respond to my query here itself; would appreciate if you could also cc it to neerahemrajani (at)


  3. May 8, 2007 5:55 am

    Neera, desi ghee is basically clarified butter and it is a saturated fat. You make it by cooking butter until all water evaporates. In India everything to do with dairy is considered very good, whether milk or butter or buttermilk or paneer. All milk products are considered very good for health. That is the traditional way and it has been like this for generations.

  4. Puneet permalink
    September 23, 2007 2:58 am

    Okay so the question is to wash or not to wash? (dal, rajma etc)

  5. September 23, 2007 7:39 am

    Ofcourse one has to wash, no doubt about that at all. In any case, where Rajma is concerned one has to not just wash but soak. The main point is not to overdo it…ofcourse it depends from where the grains have come from…I mean the source. There is also organic stuff grown without pesticides and these need minimum washing, but unfortunately these are not widely available.

  6. May 16, 2008 3:18 pm

    hello nita

    i was surfing through the net when it caught my eye, you are an leeds met alumna. if so could you please let me know. I myself i an alumni and would like to invite you for our leeds met alumni meet this year in august



    Aman, I don’t know why you got that impression. My entire education has taken place in India. – Nita.

  7. January 12, 2010 5:08 am

    I have one question I like maggi Noodles so
    much how much should be cosumed in a one month.
    I got good information from your website.
    I have problem with MSG lots of time thanks.

    How much maggi you should consume depends a lot on the rest of your diet. You have to see how much junk food you consume overall. It is certainly not a good idea to have a junk meal every other day. I personally think twice a week is the absolute limit. – Nita.

  8. Sivasakthi permalink
    September 23, 2010 12:04 am

    Hi Nita,

    Your blog is brilliant!
    I have to add my story here to highlight why your blog is very pertinent to our present day lifestyle!

    I currently live in US and in the last few years have been very indulgent on processed food and fast foods and i saw that i did not have a problem with it as several of my American friends dont cook at all, they totally depend on preprocessed prepared food. All was well until one fine day i woke up to what is called ‘Hives’. Its basically is a allergy with severe itching and inflammation, and in my case i believe is from the heavy amount of toxins that accumulated in my body.I switched to home cooked food and avoided meat and and diary and feel a lot better now. So its a lesson for all the people who dwell on these foods….even if you are fine after eating these food now, you might face the consequences later. So please please try to make the change now!


  1. Yich

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