We knew that the trouble with fructose is how hard it hits our the liver and how much it raises our triglyceride levels, which increases our risks for heart attacks. High-fructose diets also lead us to secrete more insulin, which in turn leads to more insulin resistance.

Now we are learning that this deceptively low-glycemic sweetener can cause even more trouble. The trouble with fructose isn't just insulin resistance and heart attacks, as serious as they are. And it's not even just because of...