Others were exothermic , releasing energy as they proceeded. We learned that the hydrocarbons in the ground are a source of energy because their oxidation is exothermic. If a gallon of gasoline and a bowl of cherries both oxidize in an exothermic process, why don't they do so in the tank of our car or in the bowl on the table. Our understanding of chemical kinetics deals with this problem. Molecules, Matter and Change , Peter Atkins and Loretta Jones, Third Edition, W. H. Freeman, NY, 1997.
Chemical reactions require collisions - the physical impact of the reacting molecules.
But not all collisions result in reactions. The collisions must be vigorous enough, have sufficient energy for reaction to take place. That energy is called activation energy , the energy required to take our reactants to a physical condition called the activated complex. So gasoline and oak trees and bing cherries do not burst into flame out in the open because the energy of collision between the cellulose or the hydrocarbons is insufficient to reach the level of the activated complex. But our bodies seem to convert the cherries and bananas and bread to energy without reaching extreme heat conditions.