Table sugar and “high fructose corn syrup” (HFCS) are the two big sources of added sugar in our diets. Table sugar is made by squeezing the liquid out of sugar cane or sugar beets and boiling the liquid down to sugar crystals. Table sugar is “sucrose,” which is actually two sugars bound chemically, one fructose and one glucose. Your digestive tract splits the sucrose and absorbs the fructose and glucose into your bloodstream. HFCS is corn syrup that started out as a solution of glucose in water, then was chemically modified to make about half the glucose into fructose. The food industry uses HFCS as a sweetening agent because it’s sweeter and cheaper than table sugar. In addition to table sugar and HFCS, the flours that breads, pastries, and pastas are made from come from grains, typically wheat, that contain starches. Starches are lots of glucoses stuck together. Those starches are usually called “carbohydrates” or “carbs” on the food labels. Modern flour has too much starch and too little fiber because it’s ground too finely with steel rollers.
Conventional diet wisdom talks about the calorie counts of foods. Each gram of sugar has 4 calories. The food labels show grams of sugars and other carbohydrate, which digest into sugars. Sugar in large quantities has bad effects on your brain and body because of the way it’s processed, not because of the number of calories it contains. Fats have way more calories, 9 per gram, but don’t cause the bad effects sugar does. Protein has the same calories per gram as sugar– 4 — but also doesn’t have the bad effects. Calories aren’t created equal. See below for the bad news.
Here’s Dr. Robert Lustig’s famous lecture “Sugar, The Bitter Truth.” Lustig does a good job discussing the pathology, but he’s a bit off the mark when discussing what’s human optimal, which we’ll cover in Good.