Even the simplest ingredients used in cooking, such as a banana, contain hundreds of chemical compounds. When we cook we mix several of these ingredients and apply heat, which makes a perfect environment for chemical reactions between the various compounds. Actually cooking is the art of initiating the right chemical reactions.

For a typical recipe there are billions of possible reactions between the initial compounds and there are many possible recipes with different initial compounds.

Why are none of the chemical products of this vast space lethal enough to harm a human? In other words why aren't there ingredients that must not be mixed?

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    $\begingroup$ Our bodies are also made of thousands of chemical compounds. How is that not lethal? $\endgroup$ Aug 27, 2018 at 15:03
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    $\begingroup$ @IvanNeretin Our body evolutionary evolved to work. Read my question carfully, It is not about the amount of ingredients. It is about the vast space of possible chemical products in cooking due to the number of compounds involved, i.e. that a single toxic product could be created. $\endgroup$
    – Jannick
    Aug 27, 2018 at 15:08
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    $\begingroup$ Well, then consider this: we also evolved to consume cooked meat. Then again, why would a random product be acutely toxic? Most chemicals aren't. $\endgroup$ Aug 27, 2018 at 15:13
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    $\begingroup$ Life as we know it on Earth has a fairly limited palate of chemistries. And, those chemistries are shared broadly across all of life. While some organisms have evolved to create hazardous materials (cyanide, snake venoms, ...), cooking tends to break up complex molecules into simpler ones. And, often these simpler ones are the building blocks used by all life. $\endgroup$
    – Jon Custer
    Aug 27, 2018 at 15:34
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    $\begingroup$ Those molecules may not be that reactive as you think, also, the main reaction pathways are the degradation of macromolecules, falling apart to their units $\endgroup$
    – Greg
    Aug 27, 2018 at 16:08

2 Answers 2


Cooking is potentially lethal.

Just like how going out for a walk is potentially lethal (You could get run over by a car, maybe develop a stroke, or get hit by a meteorite).

Cooking or cookery is the art, technology, science and craft of preparing food for consumption.

From this Wikipedia article on Cooking

The basic idea behind cooking, as a whole, (regardless of the actual physical process) is to either make certain inedible (or indigestible) items edible (digestible), or otherwise unsavory items more palatable.

Sometimes we have toxic substances that are rendered "safe", through the reactions that the cooking process affords. Other times, the opposite happens.

Now, does cooking (boiling, frying, baking) something generate toxicants?

Almost certainly yes. But the amount and type of toxicant(s) produced is what determines the overall lethality of the item you've cooked.

The potato chips/fries we all hold so dear almost invariably contain acrolein and acrylamides, however in trace amounts. If, you chose to let the potatoes simmer for a little too long, then you'll better be able to taste the wrath of those substances.

It is the dose, that maketh the poison (as I've discussed in a previous answer).

The cooking process does, as you point out, initiate a gamut of reactions: Some simply break down the food into products you can better digest, absorb and assimilate... while others lead to products that aren't as useful.


During cooking many harmful compounds are formed, but they are not immediately lethal. However, long exposure to the same harmful compounds can be lethal in the end. Therefore it is important to have a broad food basis, with many different raw materials and different cooking procedures. In that way, you are less exposed to the same harmful compounds all the time.

The alternative is to not eat anything, but that is more lethal in the short term.


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