EDITORIAL COMMENT Focus on the fire of life

Introduction In 1961 Max Kleiber published the book The Fire of Life [1]. It is still one of the classics in the field of animal and human bioenergetics. In his book he focussed on the parallel between animal and human life and fire, emphasizing the generalizations of biophysics rather than the differentiations of biochemistry. Life involves much more than chemical potential, work and heat. Modern nutrition is concerned with more than the supply of energy, yet energy transfer remains one of the basics in physiology in general and of nutrition in particular. Especially nowadays, with the unravelling of the human genome providing the first glimpse of candidate genes in bioenergetics, it becomes more and more clear that the concluding remark from Charles Darwin’s book The Origin of Species really points to the fire of life: ‘The evolution of higher animals directly follows. . ..from the war of nature, from famine and death. . .’ [2].