What cooking does to food

Meat Grilled Steak

By Dr Douglas Graham

Is cooking as harmful as some raw food teachers lead you to believe? After all, how can it be so terrible to gently and lovingly cook your food?

People are cooking their food at every meal, every day, all around the entire world. Heck, people have been cooking for thousands of years.

You survived decades of eating cooked food yourself, didn’t you? And the vast majority of people who count themselves as raw fooders still include substantial portions of cooked foods in their diet – usually intentionally but also unknowingly.

What actually happens when foods are heated, and is it really such a big deal? After all, don’t some foods become more digestible when cooked? The material in this article outlines the health facts associated with cooking food. It delineates the nutritional losses caused by cooking, and explains the various health compromises associated with eating food that you have heated. The claim that cooking certain foods enhances their nutritional value is also put under the bright light of scrutiny. Hopefully, once the facts are rooted from the fiction, clear decision-making will be much easier.

We’ll take a look at various classes of nutrients, and evaluate what happens to each of them when exposed to the heat of cooking. Then we can look at the bigger picture and realistically evaluate the nutritional and other health issues associated with cooking. After all, when friends and loved ones ask you, “What’s wrong with cooked food?” it is valuable to be able to give a convincing and caring answer. Who knows? Besides supporting your own efforts at eating raw, you might even be able to sway someone else to give up their (self-destructive) cooked-food habits.

How much heat is too much heat?

Cooking food leads to two broad classes of undesirable changes:

1. It destroys essential nutrients or makes them less bioavailable.
2. It causes the formation of unnatural chemical substances, the processing of which places a strain on the body’s organs. Some of these substances are also carcinogenic and/or mutagenic.

Let’s first consider the issue of nutrient loss. To date, very little scientific research has been done on the effects of cooking on the nutrient levels in food, and such research is in any case very hard to do. Figures are bandied about sometimes – we might read that cooking causes 30-98% of a certain vitamin to be lost, for example – but such figures can only ever be the roughest of approximations as there are so many variables at play. The temperature of the heat source, the distance from the heat source, the internal temperature of the food, and the duration of time spent heating (among other factors) all affect the outcome.

Science has established that enzymes, phytonutrients and water-soluble vitamins are three substances that are especially vulnerable to outright destruction when heated, even at relatively low temperatures. Minerals, on the other hand, are believed to be made less bioavailable by heat rather than being destroyed by it (although, like vitamins, minerals can be lost to us through leaching into cooking water).
So we know the above, and we also know that the negative effects of heating food are cumulative. Nutrient losses progressively increase based on the intensity of the heat and the length of exposure to it. So the higher the heat, the more rapidly the nutrients in food are corrupted, and the greater the degree of corruption. Production of toxic substances also increases dramatically with longer cooking durations and higher temperatures.

At what point does nutritional damage occur as a result of exposure to heat? The answer varies, based on several factors, including but not limited to: the water content of the food, the type and intensity of heat applied, the surface area of the food item being heated, and the nutritional makeup of the food.

But here’s an easy rule of thumb to keep in mind: if your food is being exposed to more heat than your naked hand can withstand, the heat is harming your food. This means that relatively low temperatures will result in nutrient losses. For example, if your hand is immersed for just 30 seconds in water that is only 130 F (54.4 C) your skin will suffer a third-degree burn – a clear indication of the nutritional damage that also happens to food when exposed, even this briefly, to even this low temperature.

In some countries, mangoes are dipped for 30 minutes into water that is 130 F in order to kill fruit fly larvae that may be living deep inside the fruit. If this low temperature makes it impossible for the larvae to live and maintain their metabolic functions, what do you think it does to the nutrients in the mango? Does the mango still count as “living food” if its cellular metabolism has been disrupted and mutated? Studies have revealed that enzymatic activity inside the mango ceases when the mango heats up while in the warm water. And sure enough, after the mango cools, it no longer emits its distinct, wonderful mango aroma.

Classically, nutrient damage to food as a result of exposure to heat has been said to begin, and progressively accelerate, at the following temperatures:
• Enzymes and co-enzymes begin losing effectiveness 118 F (47.7 C)
• Various vitamins show losses of function 130 F (54.4 C)
• Protein denaturing begins 161 F (71.6 C)*
* The temperature used to pasteurize milk

Partial to total nutrient loss is not the only possible nutritional damage incurred when foods are heated, however. Toxic substances also result. Antivitamins and antinutrients are formed, dangerous free radicals proliferate, and a wide assortment of health-destroying mutagens and carcinogens are created.

But you wouldn’t think this to listen to certain doctors and dieticians talking about the nutritional benefits of cooking our food. The nutritional value of foods has become ever more difficult for the layperson to discern as marketers take advantage of consumers by focusing on specific nutrients in foods, instead of the foods themselves.

Leave a Reply

Your email address will not be published. Required fields are marked *