"A lousy diet, of course, makes snacking irresistible."

Fat Head » Review: The Obesity Code: "Insulin resistance is largely about what we eat. But rolling back the effects – and perhaps preventing insulin resistance in the first place – is also about when we eat. That was the most useful message in the book for me, since I’ve already read rather a lot about the effects of foods. As Fung explains, insulin is supposed to rise after meals. But then it’s supposed to drop and stay low for several hours. 

Back when few Americans were overweight, that’s what happened — because we ate three meals per day, period. Now we add constant snacking into the mix... the real problem seems to be how often we eat between meals. 

Fung explains why that’s such a problem: The balance between the fed state (insulin dominant) and the fasted state (insulin deficient) has been completely destroyed. We are now spending most of our time in the fed state. … We are taught to eat the moment we roll out of bed. We are taught to eat throughout the day and again just before we sleep. We spend up to 18 hours in the insulin-dominant state, with only six hours insulin-deficient. 

A lousy diet, of course, makes snacking irresistible. Refined carbs jack up your blood sugar, and your body responds by flooding your bloodstream with enough insulin to give you low blood sugar. If you work in an office, I’m sure you’ve seen exactly what Fung is describing. I see people eat their white-bread sandwiches at noon, and by 3:30 they’re back in the cafeteria, trying to decide if they should raise blood sugar with a candy bar, a bag of chips, or some microwaved popcorn. Fung describes this as the vicious cycle that leads to insulin resistance. When insulin is too high, too often, cells down-regulate their insulin receptors. Then the body cranks out more insulin to try to lower high blood sugar. Then we get fatter. And hungrier. And snack more often."