Q: Was there something particular that inspired you to spread the word about the dangers of sugar and processed food?
A: In 2003 a 6-year-old named Juan came into my clinic in California. He weighed 100 pounds—he was wider than he was tall. I asked his mother what he was eating and drinking, and among other things she said he consumed many glasses of orange juice every day—which she thought was healthy. But when you're drinking glass after glass of orange juice, you're getting a lot of sugar with no fiber to help limit its absorption. Having to explain to Juan's mom that eating fruit like oranges is good but drinking sugary juices in large quantities is bad made me realize that someone needed to dispel our food myths in a way people will understand.
Q: Roughly 80 percent of all packaged foods in the United States contain added sweeteners. Sugar is everywhere—is it all that bad?
A: The problem is "refined sugar"—that is, the stuff like high-fructose corn syrup and regular table sugar, made up of glucose and fructose—which has been stripped of any nutritional value. Processed food is full of refined sugar, and it has detrimental effects: The fructose in it gets turned into liver fat, which can prevent the liver from processing insulin properly. This may lead to insulin resistance and metabolic syndrome, which puts you at greater risk for type 2 diabetes, cardiovascular disease, and stroke.
Next: The root of our sugar problem