Sifting through the sugars
Triathletes appreciate that carbohydrate, refined or not, provides fuel for their muscles, brain, and nervous system during exercise. Adequate amounts of carbohydrate in your daily diet impacts your recovery by replacing your body’s carbohydrate fuel stores from one training session to the next. Sugars are one simple form of carbohydrate found in both healthy nutrient filled foods, but also in processed foods with very little nutritional value. Smart triathletes choose not only the proper quantity of fuel, but quality fuel as well.
When we refer to “sugar” we commonly think of the white stuff that may sweeten your morning coffee, but this term refers to simple carbohydrates composed of single and double carbohydrate molecules. Glucose, fructose, and galactose are monosaccharides or single carbohydrate molecules that are the building blocks for carbohydrates found in our diet. Disaccharides are composed of two sugar molecules and include sucrose (table sugar), which is a combination of glucose and fructose, and lactose (milk sugar), which a combination of glucose and lactose. Corn syrup is a combination of glucose and fructose, and a processed sugar frequently listed on food labels.
Too put “sugars” in the context of the general term carbohydrate, complex carbohydrate are simply long chains of glucose molecules. Added sugar is simply sugars added to food such as sweeteners. Naturally occurring sugar is found in foods and not added in processing, preparation, or at the table. To make choosing the right sugars simple- when classifying sugars as good or bad, nutrients provided with these sugar containing foods should be your primary consideration.
Fructose is the natural sugar mainly found in fruits, which come power packed with nutrients and provides carbohydrate for fuel. Fruits are excellent sources of vitamins A C, fiber, potassium, carotenoids and other disease fighting phytochemicals, and fiber. Because fruits are so packed with disease-fighting nutrients, aim for at least three fresh fruit servings daily. While all fruits are nutritious, some fruits are super nutritious. Tropically fruits such as mango, papaya, kiwifruit, and guava are exceptionally high in antioxidants. Carotenoids are also found in significant amounts in deep colored fruits such as cantalope, nectarines, and apricots. Citrus fruits such as oranges and grapefruits are excellent sources of vitamin C, as are strawberries. Consume a variety of fruits for a variety of nutrients.
Lactose found in milk and yogurt is another naturally occurring sugar that comes paired with a wide variety of important nutrients. Milk and yogurt are great sources of calcium and for many individuals may provide three-fourths of their calcium intake and are fortified with vitamin D, a very important nutrient of which many Americans may be deficient. Three servings of milk or yogurt daily are recommended. Some individuals may be lactose-intolerant” and do not produce sufficient amounts of the enzyme lactase to breakdown lactose. You can buy specially formulated lactose-free milk in which this sugar is already broken down, or take lactase supplement enzymes before consuming dairy products. Yogurt has lower lactose levels than milk and if often be well-tolerated, or you can consume calcium and vitamin D fortified soy milk in place of cow’s milk.
The not so good
So it is probably no surprise that fruits and skim milk dairy sources that provide naturally occurring sugars are healthy choices. What about the not so good sugar choices? Sucrose, commonly referred to as table sugar, is mainly found in dessert and snack foods that have very limited nutritional value. Watch out especially for the added sugar high-fructose corn syrup (HCFS), which is produced by chemically altering cornstarch and is cheaper and sweeter than sucrose. HCFS found in drinks is about 55-percent fructose and 45-percent glucose, while that added to solid foods is 41% fructose, and 55% glucose. Some HFCS has higher fructose levels, at 90-percent, for an even sweeter flavor to add to low calorie products. HCFS is added to a variety of food products, included baked goods, breads, cereals, and ketchup, and soft drinks, and many other surprising items (read labels carefully). One-third of all the sugar consumed in the U.S. is the HFCS in soft drinks and other sweets that have no redeeming nutritional value.
Recently there have been healthy concerns regarding HFCS. Some experts contend that increased intake of HFCS is directly linked to the growing rate of obesity and type 2 diabetes in this country. Other experts counter that it is simply the empty calories consumed from HFCS containing products that contribute to obesity and weight gain, and these health concerns are not inherent to the sweetener itself. One recent study published in the American Journal of Clinical Nutrition compared satiety levels and calorie compensation behavior (such as possible overeating) after the consumption of HFCS, sucrose, and milk, and found no differences between the beverages. While more research is needed, all experts do agree that added sugars provide empty calorie and no fiber and nutrients.
Check food product labels carefully. Fruit juice is an excellent example of a potential natural sugar product gone bad. Any fruit juice you consume should be 100-percent juice, and not a juice drink or blend that provides some HFCS. But real fruit juice is still higher in simple sugar than whole fruit counterparts and provides no fiber. Besides keeping an eye out for 100-percent fruit juice on labels, try to avoid the cheap fillers of apple juice and white grape juice. Read the ingredient list carefully. Juices listed at the beginning are present in the greatest quantity. Juices with color tend to have more antioxidants and phytonutrients, so purple grape juice is better than white grape juice.
How much sugar?
Obviously sugars can make foods more palatable and in the context of a well-balanced diet need not be completely eliminated from your food choices. But how much added sugar is too much? Processed sugar calories should not replace appropriate servings of fruits, vegetables, whole grains, and low fat dairy products, or the quality of your diet will suffer. But unfortunately they often do just that, and push out healthy vitamins, minerals, and phytochemicals. The World Health Organization recommends limiting free sugars, which includes added sugars and the sugar present naturally in fruit juice, to no more than 10-percent of daily calories, a recommendation significantly lower than the generous National Academy of Science guideline of 25-percent, which many health experts found much too high.
Try to minimize sugar in your diet, not eliminate it completely. The occasional dessert or candy after a meal is fine, as part of a well-balanced diet. If your active lifestyle demands an intake of 2400 calories daily, your sugar intake should not exceed 240 calories, leaving room for some treats in a daily diet filled with wholesome choices.
The Nutrition Facts label does not distinguish between added sugar and natural sugars in a food, as only the “total sugars” are listed, and can include naturally occurring sugar choices in the food as well. But you can determine if added sugars are a major ingredient by referring to the ingredient list. The terms below are added sugars found in foods. The closer the terms are to the beginning of the ingredient list, the greater the amount of added sugar in the product.
|Beet juice||Brown rice syrup||Cane syrup|
|Corn syrup||Corn sweetener||Crystalline fructose|
|Dextrose||Evaporated cane juice||Fructose|
|High fructose corn syrup||Invert sugar||Malt syrup|
Monique Ryan, MS, RD is the author of Sports Nutrition for Endurance Athletes, 2nd edition (VeloPress 2007). Click here to view more about the book or purchase. She was a member of the Athens 2004 Performance Enhancement Teams for USA Triathlon and USA Cycling Women’s Road Team. She is owner of Personal Nutrition Designs and offers her sports nutrition “E Program” at www.moniqueryan.com.