Most athletes recognize that carbohydrates are essential to fuel optimal athletic performance, but fad diets have given the general population the impression that carbohydrates are “bad” when it comes to weight control and overall health. This is not the case when minimally processed carbohydrates are consumed in appropriate portion sizes.
Simple and Complex Carbohydrates
Carbohydrate quality was once decided based on whether the carbohydrate was classified as a simple carbohydrate (mono-or disaccharides) like table sugar or a complex carbohydrate (oligo-and polysaccharides) like brown rice. This classification branded simple carbohydrates as nutrient-poor and “un-healthy” and complex carbohydrates as more nutrient-dense and “healthy.” The belief was the digestion rate, and thus postprandial effect on blood glucose, was based primarily on the length of the carbohydrate chain, with short chains causing a more pronounced blood glucose response and long chains causing only a small bump in blood glucose. Today, carbohydrate quality is better determined by considering the food’s nutrient value, effect on blood glucose levels, and extent of processing. Although no one scale or formula can completely determine carbohydrate quality, many health experts use glycemic index (GI) and glycemic load (GL) when considering carbohydrate quality.
Glycemic Index & Load
Glycemic Index ranks carbohydrates based on their blood glucose response: high-glycemic index foods enter the bloodstream rapidly, causing a large glucose spike. This rapid increase in glucose stimulates release of insulin and a subsequent insulin spike. Insulin promotes glucose uptake in muscle cells and fat deposition in adipose tissue. Two to four hours after consumption of a high-glycemic index meal residual effects from high insulin levels can cause a rapid drop in blood sugar and hypoglycemia. Low-glycemic index foods such as nonstarchy vegetables, whole fruit, whole grains, and legumes are digested more slowly and cause a smaller glucose increase and a small boost in blood insulin levels. Highly processed, refined starches and sugar tend to have a higher glycemic index and have been associated with negative health consequences such as heart disease and diabetes.
Although valuable, the glycemic index does not account for the caloric amount consumed of one product. For example, carrots have a higher glycemic than a candy bar. Glycemic index is based on a reference amount of carbohydrate (50 g). Glycemic load (GL) accounts for portion size (GL =GI x grams of carbohydrate/ l 00). A food can have a high glycemic index but a low glycemic load. For example, carrots have a high glycemic index. A person would need to eat several cups of the carrots to equal 50 grams of carrots. Because the typical serving size is approximately one-half cup, the glycemic load is small. Also, carbohydrate-containing foods that are also moderate to high in fat or protein, fiber, and other nutrients and that are minimally processed may have a high glycemic index but a low glycemic load.
A growing body of research supports that eating a diet with mostly lower glycemic index carbohydrates may offer health benefits including weight control, decreased risk of diabetes and heart disease and reduced morbidity in those individuals. Also, food with a low glycemic load are commonly more nutrient dense and provide more nutrients per calorie. For example, 16 ounces of soda has about the same amount of carbohydrates as two medium-sized apples, but the glycemic load of the soda is much higher. The two apples provide more vitamins, minerals, and fiber compared to the soda, making the apples more nutrient dense. Overall, high-GI foods are good for refueling and athletic performance, but as far as heart health goes, lower GI foods may be a better choice. The goal is to find a balance.
In addition to considering a carbohydrate’s glycemic index or load, an important consideration when evaluating carbohydrate quality is the food’s fiber content. Fiber is classified as functional fiber and dietary fiber. Together. dietary and functional fiber comprise “total fiber.”
Functional fiber is defined as an isolated non-digestible carbohydrate that may have beneficial physiological effect in humans. Functional fiber is typically available in both natural and synthetic dietary supplements which claim to offer such benefits as improved gastrointestinal symptoms, weight loss, reduced cholesterol and colon cancer prevention. among other claims. On the food label functional fiber shows up as isolated, non-digestible plant, animal, or commercially produced carbohydrates. It is typically added to foods.
Dietary fiber is the fiber naturally found in certain foods. It is further classified as high viscosity and low viscosity. High viscosity fiber typically those referred to as soluble fiber include gums, pectin and psyllium seeds.
These fibers slow gastric emptying or the passage of food from the stomach into the intestines. Consequently, once mixed with digestive juices they become gel-like, causing an increased reeling of fullness. Also, the delayed gastric emptying slows the release of sugar into the bloodstream, which may help attenuate insulin resistance. High viscosity fibers also can interfere with the absorption or fat and cholesterol and the recirculation of cholesterol in the liver, which may decrease cholesterol levels.
Low viscosity fibers previously referred to as insoluble fiber such as cellulose, hemicellulose and lignin play an important role in increasing fecal bulk and provide a laxative effect.
Fiber serves many important and beneficial roles in the human body. The average American consumes far less than the recommended 14 grams per 1,000 calories consumed per day-or the approximately 25 to 35 grams per day for most adults. With increased consumption of fruits, vegetables, legumes. and whole grains, most Americans could easily achieve this.
Natural Sugar versus Processed Sugar
No matter what form sugar comes in, it’s a simple carbohydrate that is broken down for energy. The sugar that’s in a piece of fruit is made up of fructose and glucose, just like processed sugar. Most fruits are 40-55% fructose (although this varies depending on the fruit—cranberries have 20% fructose and apples are 65% fructose). Table sugar is 50% fructose and 50% glucose. Your body processes fructose in the liver so it won’t trigger an insulin response, while glucose starts to breakdown in the stomach and requires insulin to be released into the bloodstream so it can be metabolized quickly. Neither glucose nor fructose is better than the other, when looked at alone. It’s how it’s packaged that makes the difference.
Sugar Health Impact
The type of sugar (natural or refined) that you’re eating impacts your health differently. Natural sugar -the sugar that comes in fruit – is packaged with fiber, water, antioxidants, vitamins, minerals and disease-fighting phytonutrients and other nutrients that improve your health. (Natural sugar is also found in milk and cheese and is called lactose.) Refined sugar comes from sugar cane or sugar beets, which are both processed to extract the sugar. Usually, this sugar is a combination of glucose and fructose, called sucrose.
Manufacturers add chemically produced sugar, typically high fructose corn syrup, to many foods and drinks. Other than providing a source of energy that the body can use, processed sugar doesn’t provide any benefits to the body—it lacks the fiber and health-promoting nutrients that occur in natural sugar sources. By contrast, processed sugar can harm the body when overeaten and may contribute to inflammation, disease, weight gain and obesity. This is why refined sugar is known as “empty calories”—calories without nutrients that benefit the body.
Refined Sugar Highs and Lows
There is a significant difference in how you feel after you eat natural sugar versus refined sugar. Refined sugar causes you to experience energy highs and lows and sugar cravings.
Refined sugar (think candy and cakes) has no fiber to slow down its absorption, so it’s digested rapidly and enters the blood stream very quickly, causing a (blood) sugar rush/high. This sugar high, in turn, causes the body to release a surge of insulin, which quickly removes the sugar from the blood to the tissues. This is what is often known as a sugar crash or “low,” and is the body’s way of signaling that it needs a quick pick-up and the quickest pick-me-up is more sugar! This launches a vicious cycle of highs and lows that lead to a deep craving for more sugar. At the same time, sugary foods don’t provide the body any of the nutrients it needs to feel good and to sustain energy.
Natural sugar provides a longer source of energy without crashes. Natural sugar comes packaged in fruit—and fruit is a good source of fiber, which slows down the digestion of glucose so you don’t get the energy high/insulin spike followed by a sugar crash like you do when you eat refined sugar. Fruit also contains water, which helps to prevent dehydration and the tired, drained feeling that comes with it that mimic blood-sugar dips.
Fruit Juice and Fiber
Fruit juice is an important exception to the above. If the fiber has been removed from the fruit juice it will differ from fruit in how it affects energy levels. While it still provides important nutrients that the body uses for good health, portions should be limited to prevent a blood-sugar spike and to prevent weight gain.
Added Sugar Guidelines
Overall, there is room in a wholesome, nutrient-packed diet for a small indulgence in added sugar. The current Dietary Guidelines state that no more than 10% of total daily calories should come from added sugars. The amount we “need” is less than that, but exceeding that amount can contribute to weight gain, diabetes, heart disease and poor dental health (among others). This does not necessarily include pre- and post- HIIT workout nutrition.
Most people overconsume added sugars in their diet without realizing it and it’s beneficial for most people to make an effort to avoid added sugars because they can contribute to weight gain and take the place of other nutrient-rich foods. Trying to satisfy sweet-tooth cravings with naturally sweet foods, like desserts made with fruits is suggested. This helps people to appreciate less-sweet flavors, while consuming added nutrients.
Food Labels and Added Sugar
One of the easiest ways to avoid added sugars is to look for them on ingredient labels. Be aware that if you purchase a sweet food and don’t see the word honey or sugar or another sweetener that you recognize on the label, this doesn’t mean there isn’t added sugar. Instead, it probably means that the sugar is hiding under a different name. The good news is that added sugars will be listed on the new Nutrition Facts Labels (released by 2018).
Until then, be mindful that added sugars in foods and drinks may be listed on labels as: anhydrous dextrose, brown sugar, cane crystals, cane sugar, corn sweetener, corn syrup, corn syrup solids, crystal dextrose, evaporated cane juice, fructose sweetener, fruit juice concentrates, high-fructose corn syrup, honey, liquid fructose, malt syrup, maple syrup, molasses, pancake syrup, raw sugar, sugar, syrup and white sugar and more.
Added sugars include any type of “syrup” or any word ending with “ose.” Common added/hidden sugars include: brown rice syrup, corn syrup (solids), high-fructose corn syrup, dextrose, agave nectar, honey, brown sugar, malt/malt syrup, (evaporated) cane juice, fructose, glucose, invert sugar and molasses.
Fall in love with the foods that are good for you! Your body will thank you. You’re Welcome!
Have a great day!
Coach Tim Garrett