Gary Taubes is an award-winning science journalist and the author of several books on nutrition, including Why We Get Fat (2011) and Good Calories, Bad Calories (2007). Why We Get Fat was the first one I read and it taught me so much, including how we have been misled for so long about how certain foods affect metabolism and health.
Mr Taubes has just published The Case Against Sugar, where he demonstrates how sugar alters hormones and metabolism, and is the major contributor to the current epidemic of obesity and diabetes, among other metabolic disorders.
Aeon magazine has published a chapter online from The Case Against Sugar and it is a good read. A few excerpts from this below.
As it turns out, virtually all hormones work to mobilize fatty acids from fat cells so that they can then be used for fuel. The one dominant exception to this fuel-mobilization signaling is insulin, which partitions how we use the fuels we consume: in particular, it directs fat cells to store fat, while facilitating the uptake and oxidation of glucose (blood sugar) by muscle and organ cells. In other words, when insulin is secreted – primarily in response to the carbohydrates in our diet – it directs our cells to burn carbohydrate as fuel and store fat.
Yalow and Berson themselves described insulin as a ‘lipogenic’, or fat-forming hormone. This lipogenic signal must be turned off, or at least muted significantly, for the fat cells to release their stored fat and for the body to metabolize it for energy. […] The more we consume carbohydrates, though, and particularly sugar, the higher our insulin levels will be.
Insulin is secreted in response to rising blood sugar, and rising blood sugar is a response to a carbohydrate-rich meal. Sugar is implicated, in particular, because its chemical structure includes a large proportion of the carbohydrate fructose, and fructose is preferentially metabolized in the liver. As such, it is a prime suspect for the fat accumulation in liver cells that is hypothesized to be the trigger of insulin resistance itself.
Hence, the same dietary factors – sugars and refined grains – trigger both obesity and diabetes. By focusing on the problems of eating too much and exercising too little, public health authorities have simply failed to target the correct causes.