The medical community accepted Reaven's notion of insulin resistance but balked at Syndrome X.

FORBES: The Unknown Epidemic

Reaven saw all of these problems as a result of insulin resistance, and his term, Syndrome X, started to take off.

FORBES: Inventing A New Heart Disease

In a paper in Trends in Endocrinology and Metabolism they argue that insulin resistance is another side-effect of metabolic syndrome whose cause is lipid molecules poisoning tissues in which they are not supposed to be present in large quantities.

ECONOMIST: Metabolic syndrome

In other words, chronically eating added sugar reduces BDNF, and then the lowered levels of the brain chemical begin contributing to insulin resistance, which leads to type 2 diabetes and metabolic syndrome, which eventually leads to a host of other health problems.

FORBES: What Eating Too Much Sugar Does to Your Brain

The metabolic syndrome criteria are not particularly good at identifying insulin resistance.

FORBES: Inventing A New Heart Disease