Two new books on nutrition, The Secret Life of Fat, by Sylvia Tara, and The Case Against Sugar, by Gary Taubes are reviewed in a recent New Yorker: Is Fat Killing You, or Is Sugar? “Both present a range of cutting-edge dietary research, both say that fat is unfairly maligned, and both inadvertently end up revealing that the science behind their claims is complex and its findings hard to translate into usable advice,” Jerome Groopman says.
Tara’s book provides useful information on the biology of fat. White fat stores energy. Brown fat burns energy for body heat. Groopman reports:
A third type, beige fat, was identified some five years ago; during exercise, it receives messages from our muscles to morph into brown fat. Moreover, fat should not be characterized simply as inert blubber. It is the vehicles by which our cells receive certain essential nutrients, like Vitamins A, D,. E., and K. The myelin sheaths around our nerves are eighty per cent lipids, “which means fat is actually required to think,” Tara writes. Studies by Jeffrey Friedman, at the Rockefeller University, have shown that the hormone leptin travels from fat cells to the hypothalamus, a part of the brain which is involved in regulating appetite. ‘Friedman’s discovery redefined fat,” Tara writes. “It was a verifiable endocrine organ with wide influence to our bodies. Through leptin, fat could talk. It could tell the brain to stop eating.”
However, Groopman concludes that Tara’s speculation that viruses may cause obesity relies on research that is obscure and unconvincing.
In The Case Against Sugar, Gary Taubes argues that dietary sugar is the cause of diabetes, heart disease, cancer, Alzheimer’s, and other illnesses. Groopman says:
Ultimately, Taubes’s indictment of sugar as the leading culprit in virtually all modern Western maladies doesn’t provide enough evidence for us to convict. That doesn’t mean sugar is without dangers: it certainly plays a role in the development of obesity, to say nothing of dental cavities. But these are lesser charges, and they make for a less dramatic headline.