Part 7: Bread, Sugar, and the Glycemic Index Based on the book “What to Eat” by Marion Nestle
The starting ingredient for wheat bread is wheat flour. If all three parts of the grain (bran, germ, endosperm) remain after grinding the flour is whole wheat. White flour is refined; it contains 70-80% of the components of the original grain and is mostly endosperm (the nutrient rich bran and germ are not there). White flour bakes into lighter and softer loaves but these are nutritionally inferior to those made from whole grains. Nearly all bread contains high fructose corn sweeteners and many feature molasses or honey. The clutter and sweetness are there for a reason: to disguise the unpleasant chemical taste of dough conditioners and preservatives that keep the breads soft and free of molds for weeks at a time. The remaining ingredients are cosmetic to make the bread look attractive. Other than the kind of wheat, commercial breads are the same. The bread industry, however, classifies soft sliced bread into distinct categories: soft white breads made from processed enriched white flour, soft italian and french breads made from processed enriched white flour, soft premium enriched white sandwich breads, soft enriched white bread made with whole grain, and soft whole grain sandwich bread. I don’t eat bread because I can’t have gluten but if grocery store breads are your only choice you have to deal with what you find. Nearly all commercial sliced breads will be loaded with cosmetic ingredients. If you care about taste look for commercial breads with the fewest ingredients and the lowest number of additives. If your first consideration is nutrition, choose breads labeled 100% whole grain; anything else is just white bread (even whole wheat is just dyed brown). The preference for white bread has nutritional consequences: the nutrient losses are significant by anyone's standards. Foods made from wheat flour account for about 20% of the calories in American diets, bread alone counts for 9%, cakes and pastries 6%, pasta 3%, and all other crackers, pretzels, etc 2%. Most of these are made from refined white flour. Now let’s dive into glycemic index and glycemic load. When it comes to the glycemic index the lower the better. To understand what this is about you need to know that carbs come in two forms: starch and sugar. Both kinds are made up from units of sugar; they differ only in the size and number of sugar molecules and function. Sugars are simple carbs that are composed of a single sugar glucose or fructose, sucrose, and lactose. Starch is a complex carb made of glucose molecules linked together in long branching chains. Starch is what you get when you eat potatoes, rice, pasta, bread, crackers, cookies, and cakes. Starch is like a gel. When you eat starch, digestive enzymes in your small intestine attack the gel by breaking up the molecules into smaller and smaller pieces until it is just one molecule of glucose that you can easily absorb. Glucose is the primary fuel for your brain and muscles and your body does everything it can to make sure you have enough at all times. Once glucose is absorbed from the intestine into the bloodstream blood glucose levels go up and you start secreting insulin to get the sugar where it needs to go. When too much glucose comes in at once, your body gets overwhelmed and creates too much insulin and then your blood sugar drops too much, your muscle glucose storage gets full, and what's leftover turns into fat. Fiber slows down the absorption of glucose which is why a diet high in fiber will keep those problems at bay. The glycemic load considers the total amount of rapidly absorbable carb in the food you eat as well as the glycemic index of that food because it takes the quantity of food into consideration the glycemic load is the factor that counts. To avoid fruits and veggies because they may have a high glycemic index makes no sense, their glycemic load is low and that's what really matters. The glycemic index alerts you to the good things that happen when you eat food with a low glycemic load—fruits, veggies, whole grains, lean meats and fish, and low fat dairy—exactly the foods recommended for good health. The glycemic index also alerts you to the undesirable effects of eating lots of starchy processed foods and foods high in sugar. Speaking of sugar there are many different kinds. The first is sucrose, common refined table sugar, the product extracted from sugar cane and sugar beets. When you say sugar the sugar association wants you to think sucrose, but that would be misleading. Any nutrition or biochemistry book will tell you that sugar refers to many kinds of caloric sweeteners. In sucrose, the glucose and fructose are stuck together. In high fructose corn syrup and other sweeteners made from corn, the glucose and fructose are separate. Enzymes in the digestive system quickly split sucrose into its two sugars so the body can hardly tell the difference. Sucrose, fructose, and glucose are sugars. One or another of these sugars, singly or together, also show up in foods as dextrose, fruit juice concentrates, honey, molasses, and high fructose corn syrup and other corn sweeteners. All are sugar. Corn syrup starts off as corn starch. Starch is not sweet so chemists treat cornstarch with enzymes to break the gel into smaller pieces, this process ends up as corn syrup. Sucrose and corn sweeteners both end up as glucose and fructose in the body and both are rapidly absorbed forms of carbs. Also both are common constituents of junk foods and add non nutritious calories to the diet. The low wholesale cost explains why food companies love to put corn sweeteners in their products. The more corn sweeteners in the product the cheaper the product is to make. If a food product does not cost much you are more likely to buy it and to buy it in larger sizes and more often. That is why low prices, wonderful as they are for your budget, are not so wonderful because they encourage you to eat more. Some companies add a few vitamins to desserts which could lull you into thinking that it is fine to eat sweets instead of more nutritious foods that naturally contain a much wider range of vitamins and other good things. Adding vitamins to sugary foods blurs the distinctions among food categories and moves desserts into the nutritional mainstream which are everyday foods instead of those foods that should only be eaten occasionally. Adding vitamins is an eat more strategy, it is not really about your health. If you need more vitamins you are better off getting them from healthier foods or a supplement. If health authorities actually advised you to eat less sugar you might be inclined to follow their advice. The sugar industry's job is to convince you and government agencies that there is no reason for anyone to eat less sugar and it is relentless in doing so. Attributing a disease to any one food or food component is always problematic because diets contain many foods and foods contain a great many components that singly and collectively can affect health. Even so, plenty of other research, circumstantial evidence, and direct observations about sugars and health should be enough to convince anyone other than an industry defender that sugary foods cause metabolic problems and promote weight gain. Common sense tells you that eating ounces of sugars ar any one time without the modulating effects of fiber and other food components will raise blood sugar beyond where it needs to be. If you cannot help liking sweet foods, it is for a good reason. Humans are born with a predilection for sweetness to simulate sucking reflexes for breastfeeding. That innate nature doesn’t always go away. Although most of us know that cereals contain a lot of sugar we see health claims on them that tell you that you can lose weight if you consume their product (i.e. Special K). Remember you can eat nothing but candy bars and lose weight if you don't eat too many of them so take the health claims on sugary items with a grain of salt. Look for three things in ready to eat cereal: a short ingredients list, lots of fiber, and little or no added sugar. What about organic cereal? There are only two differences between organic and conventional cereal, the ingredients in an organic cereal are organic and its higher priced, nutritionally they are the same.