Thick, clot-forming blood is very helpful if a tiger gets a bite of your arm. But if you’re constantly making your blood go all thick and sticky, it’s more likely to clump up into a plug and cause a heart attack or stroke. All that extra sugar-fuel in your blood is exactly what you need for a desperate burst of muscular energy. But regularly flooding your blood with sugar-fuel—particularly if you don’t make a point of exercising it away afterward—makes you more likely to develop diabetes.
