4
" The idea of specific populations predisposed to obesity is encapsulated in a notion now known as the thrifty gene—technically, the thrifty-genotype hypothesis—that is now commonly invoked to explain the existence of the obesity epidemic and why we might all gain weight easily during periods of prosperity but have such difficulty losing it. The idea, initially proposed in 1962 by the University of Michigan geneticist James Neel, is that we are programmed by our genes to survive in the paleolithic hunter-gatherer era that encompassed the two million years of human evolution before the adoption of agriculture—a mode of life still lived by many isolated populations before extensive contact with Western societies. “Such genes would be advantageous under the conditions of unpredictably alternating feast and famine that characterized the traditional human lifestyle,” explained the UCLA anthropologist Jared Diamond in 2003, “but they would lead to obesity and diabetes in the modern world when the same individuals stop exercising, begin foraging for food only in supermarkets and consume three high-calorie meals day in, and day out.” In other words, the human body evolved to be what Kelly Brownell has called an “exquisitely efficient calorie conservation machine. "
― Gary Taubes , Good Calories, Bad Calories: Challenging the Conventional Wisdom on Diet, Weight Control, and Disease
7
" The belief in physical activity as a method of weight control is relatively new, however, and it has long been contradicted by the evidence. When Russell Wilder of the Mayo Clinic lectured on obesity in 1932, he noted that his patients tended to lose more weight with bed rest, “while unusually strenuous physical exercise slows the rate of loss.” “The patient reasons quite correctly,” Wilder said, “that the more exercise he takes the more fat should be burned and that loss of weight should be in proportion, and he is discouraged to find that the scales reveal no progress. "
― Gary Taubes , Good Calories, Bad Calories: Challenging the Conventional Wisdom on Diet, Weight Control, and Disease
13
" If blood-sugar levels increase—say, after a meal containing carbohydrates—then more glucose is transported into the fat cells, which increases the use of this glucose for fuel, and so increases the production of glycerol phosphate. This is turn increases the conversion of fatty acids into triglycerides, so that they’re unable to escape into the bloodstream at a time when they’re not needed. Thus, elevating blood sugar serves to decrease the concentration of fatty acids in the blood, and to increase the accumulated fat in the fat cells. "
― Gary Taubes , Good Calories, Bad Calories: Challenging the Conventional Wisdom on Diet, Weight Control, and Disease
14
" In retrospect, the influential figures in the clinical investigation of human obesity in the 1970s can be divided into two groups. There were those who believed carbohydrate-restricted diets were the only efficacious means of weight control—Denis Craddock, Robert Kemp, John Yudkin, Alan Howard, and Ian McLean Baird in England, and Bruce Bistrian and George Blackburn in the U.S.—and wrote books to that effect, or developed variations on these diets with which they could treat patients. These men invariably struggled to maintain credibility. Then there were those who refused to accept that carbohydrate restriction offered anything more than calorie restriction in disguise—Bray, Van Itallie, Cahill, Hirsch, and their fellow club members. These men rarely if ever treated obese patients themselves, and they repeatedly suggested that since no diet worked nothing was to be learned by studying diets. "
― Gary Taubes , Good Calories, Bad Calories: Challenging the Conventional Wisdom on Diet, Weight Control, and Disease
15
" The “remarkable sodium and water retaining effect of concentrated carbohydrate food,” as the University of Wisconsin endocrinologist Edward Gordon called it, was then explained physiologically in the mid-1960s by Walter Bloom, who was studying fasting as an obesity treatment at Atlanta’s Piedmont Hospital, where he was director of research. As Bloom reported in the Archives of Internal Medicine and The American Journal of Clinical Nutrition, the water lost on carbohydrate-restricted diets is caused by a reversal of the sodium retention that takes place routinely when we eat carbohydrates. Eating carbohydrates prompts the kidneys to hold on to salt, rather than excrete it. The body then retains extra water to keep the sodium concentration of the blood constant. So, rather than having water retention caused by taking in more sodium, which is what theoretically happens when we eat more salt, carbohydrates cause us to retain water by inhibiting the excretion of the sodium that is already there. Removing carbohydrates from the diet works, in effect, just like the antihypertensive drugs known as diuretics, which cause the kidneys to excrete sodium, and water along with it. This "
― Gary Taubes , Good Calories, Bad Calories: Challenging the Conventional Wisdom on Diet, Weight Control, and Disease
20
" Our brains, for instance, are 70 percent fat, mostly in the form of a substance known as myelin that insulates nerve cells and, for that matter, all nerve endings in the body. Fat is the primary component of all cell membranes. Changing the proportion of saturated to unsaturated fats in the diet, as proponents of Keys’s hypothesis recommended, might well change the composition of the fats in the cell membranes. This could alter the permeability of cell membranes, which determines how easily they transport, among other things, blood sugar, proteins, hormones, bacteria, viruses, and tumor-causing agents into and out of the cell. The relative saturation of these membrane fats could affect the aging of cells and the likelihood that blood cells will clot in vessels and cause heart attacks. "
― Gary Taubes , Good Calories, Bad Calories: Challenging the Conventional Wisdom on Diet, Weight Control, and Disease
Good Calories, Bad Calories: Challenging the Conventional Wisdom on Diet, Weight Control, and Disease