Pure sugar, and various carbs that turn to sugar once they are consumed, like white bread, tell the pancreas to produce the hormone insulin to get the sugars out of the blood and into the organs where they are needed.
If a lot of sugars are consumed, a lot of insulin is released, which reduces the blood-sugar level so quickly that "new cravings are created, requiring more quick carbohydrate fixes," Agatston claims.
His solution: limit bad carbs, like white potatoes and highly processed foods that have had their nutrients beat out of them, because those foods are absorbed quickly, causing a sudden rise in insulin, thus triggering the desire for more food. Instead, he says, dine on good carbs, like broccoli. And skip the doughnut.
Not all experts agree with Agatston, of course, except for the part about skipping the doughnut.
One reason there is so much debate on this terribly important issue of weight control is the lack of a clear understanding of how the brain reacts to various stimuli. After tons of research, for example, scientists are just now learning that the brain yearns for calories, independent of taste.
That's true among mice, at least, and it's almost certainly true for humans as well.
Lee Dye is a former science writer for the Los Angeles Times. He now lives in Juneau, Alaska.