Max RubnerBorn 2 Jun 1854; died 27 Apr 1932 at age 77.Physiologist who showed the available energy content of food was the same whether the material was consumed organically or merely burned (1894). He determined that no single type of food produced energy, but that the body variously made ready use of carbohydrates, fats and proteins. In 1883, he used geometry to compare metabolic rates of animals of different sizes. Thus, if an animal is N times taller than another, it has surface area N2 greater and mass N3 greater. Thus total metabolic rate (dependent on heat loss over surface area, N2), would be proportional to M2/3. Specific metabolic rate (the energy burnt M2/3, per unit of mass, M) would be proportional to M1/3. It took 50 years before this simple explanation was improved.