Dietary models of obesity: Sclafani 1987 (high-sugar diets); Oscai et al. 1984 (high-fat). See also Wade 1982. Regaining weight after fasting: Levitsky et al. 1976.“It doesn’t matter…”: Interview, Irving Faust. Transgenic animals: See, for instance, Bluher et al. 2003; Cohen et al. 2002. accompanied by just such a wave of electrical excitation. Consensus Conference. 1985.“Lowering Blood Cholesterol to Prevent Heart Disease.”JAMA. April 12; 253(14):2080–86. Regulation by hormones and the nervous system is then layered onto these baseline mechanisms to deal with the vagaries of the external environment, providing the moment-to-moment and season-to-season fine-tuning necessary for the body to work at maximum efficiency. Hormones modify this flow of fatty acids back and forth across the membranes of the fat cells, and they modify the expenditure of energy by the tissues and organs. Hormones, and particularly insulin—“even in trace amounts,” as Ernst Wertheimer explained—“have powerful direct effect on adipose tissue.”