The assumption that a pound of human fat tissue represents about 3500 calories in the context of weight loss or gain is based on a review of previous observations and experiments by Max Wishnofsky published in 1958. He noted that previous research suggested that a pound of human adipose tissue is 87% fat, which equals 395 grams of fat. He further assumed that animal fat contains 9. 5 calories per gram. Thus one pound of human fat tissue should contain 3750 calories. He then critically analyzed the relevant literature and applied a number of additional assumptions, including that the diet contains sufficient protein and that the person is in glycogen and nitrogen (protein) equilibrium, leading to most weight loss stemming from the catabolism of fat. He concluded that a 3500 calorie excess or deficit for a person meeting his assumptions, would lead to the gain or loss, respectively, of one pound of body weight. He noted that if the assumptions he made are not met, a deficit of 3500 calories would not necessarily equate to a pound of weight loss.