Why do the chemical reactions involved in cooking require heating

Why do the chemical reactions involved in cooking require heating  

Cooking is an applied form of organic chemistry, since the molecules in the food occur naturally. We heat the food because the reactions occurring in, say, a pie dish require energy and an oven is simply an excellent means of supplying large amounts of energy over extended periods of time. 

The natural ingredients in food are all organic chemicals, and it is rare for organic reactions to proceed without an additional means of energy, which explains why we usually need to reflux a reaction mixture. 

It is easy to see why an endothermic reaction requires energy to react - the energy to replace the bonds, etc. must be supplied from the surroundings. But why does an exothermic reaction require additional energy Why do we need to add any energy, since it surely seeks to lose energy  

At the heart of this form of kinetic theory is the activated complex. In this context, the word activated simply means a species brimming with energy, and which will react as soon as possible in order to decrease that energy content. 

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