Health is the level of functional and/or metabolic efficiency of an organism at both the micro(cellular) and macro(social) level. An increasing measure of the health of populations is height, which is strongly regulated by nutrition and health care, among other standard of living and quality of life matters. The study of human growth, its regulators and its implications is known as auxology.
So if I choose a taller cat at the SPCA it should be healthier? o.O