What You Need to Know About Sugar
n 2009, an hour and a half lecture about sugar and obesity that I gave to the public was posted to YouTube. Given its scientific content, I wasn’t even sure if my family members would watch it. Three million views later, the video is still going strong, and my theories about sugar’s toxic effects on the body are gaining traction. I still believe that one particular form of sugar—fructose—is toxic in high dose. Yet there is still a lot of confusion about this dietary bogeyman. Here are five myths about sugar and some important distinctions about how our body processes its different forms.
Myth 1. A carbohydrate is a carbohydrate; they all have the same calories.
Half true. There are three molecules that make up all the various kinds of carbohydrate: glucose, galactose, and fructose. All three molecules have the same caloric density—4.1 kcal/gm — which is why people erroneously conclude that “a calorie is a calorie.” Glucose is what’s found in starch; it’s the energy of life; all cells in all organisms on the planet burn glucose to make energy. Galactose (the molecule exclusively found in milk sugar) is rapidly converted in the liver to glucose. Fructose (the molecule that makes sugar sweet) is also metabolized in the liver, but any excess is converted into liver fat. Chronic and excess alcohol or fructose exposure both cause fatty liver disease, which drives the pathologic process of insulin resistance, and causes the same chronic diseases — obesity, heart disease, and diabetes.