So What Comes First: The Obesity or the Insulin Resistance? And Which Is More Important?

Unless it is religion, there is no field of human thought in which sentiment and prejudice take the place of sound judgment and logical thinking so completely as in dietetics (1) (p. 191). Once upon a time, humans were for the most part lean and, apart from susceptibility to infections and trauma, perhaps healthier than today (2). The most long-lived in those populations may also have lived for as long as do modern elderly. All were also less likely to die from the “chronic diseases of lifestyle” (2) that have become increasingly prevalent in the past century. There are two contrasting explanations for why so many modern humans suffer from that constellation of chronic diseases—obesity, hypertension, type 2 diabetes mellitus, coronary heart disease, dementia, and cancer—that were much less common even as recently as the 1970s (3). The first implies that our current predicament is largely of our individual making. According to this reasoning, over the past 50 years humans have simply become, well, just progressively lazier and more voracious. The resulting sloth and gluttony means that we now willfully eat too many calories, leading to an obesity pandemic that began in the early 1980s (4). As our obesity increases, storage of triglyceride in the abdominal organs, especially the liver, causes the key associated complications of obesity—specifically insulin resistance (5), hypertension (6), nonalcoholic fatty liver disease (7), and atherogenic dyslipidemia (8)—all of which explain our current epidemic rates of coronary heart disease (9), dementia (10), and even perhaps cancer (11). The less-than-subtle inference is that it is our own bad “lifestyle” choices that trigger the corpulence that causes all these chronic medical conditions (“of lifestyle”). This model fits nicely with a paternalistic model of medicine. When our medical advice and management fail, ultimately it is the \ldots