Empty calories versus nutrient density — what does that mean anyway?
Think of it as one cup of a sugared soft drink versus one cup of low-fat milk. Both have about 100 calories, but the cola has zero nutrients. The milk contributes 3 percent of the average daily adult need for folic acid and vitamin C, 8 percent of thiamin, 11 percent of potassium, 16 percent of protein and vitamin A, 24 percent of riboflavin and 30 percent of calcium. Now that is nutrient density.
Nutrient density is the amount of nutrients in a food relative to the amount of calories. The higher level of nutrients and the fewer number of calories, the more nutrient dense the food is.
Overweight and obesity have doubled in the United States in the last 20 years. It is not surprising that these statistics paralleled the increase in consumption of sugared soft drinks.
The results of several national self-reported food surveys have shown that many nutrient-rich foods have been replaced by sugared soft drinks and fruit drinks. In fact, in the last 20 years, sugared soft drink consumption has increased by 300 percent. Each 12 ounces of sugared soft drink consumed daily has been shown to increase the risk of obesity by 60 percent.
Sweetened drinks are a particular problem since the empty calories in liquid form are easily over-consumed. These calories not only replace nutrient-dense foods, but add additional caloric load. One study reported that it was not uncommon for teenagers to get 500 to 1,000 calories per day from sugar-sweetened drinks.
The use of high fructose corn syrup (HFCS) in foods and beverages now represents more than 40 percent of the sweeteners in foods and beverages in the United States. It is the major caloric sweetener in sugared soft drinks, fruit drinks, sports drinks and teas. A huge array of HFCS-sweetened food products includes ketchup, yogurt, cereals, baked goods, gum, jams and jellies. Fat-free products may contain an inordinate amount.
Some research suggests that HFCS may be digested and metabolized differently in the body than sucrose causing even more significant weight gain. Though these findings may be preliminary, HFCS is a major hidden source of empty calories in many foods nonetheless.
But what about fruit juice? The word juice is the key. When shopping for juice, be sure the label says 100 percent fruit juice with no added sugar and not fruit drink. Even 100 percent juice is high in natural sugars. The American Academy of Pediatrics recommends that children limit daily amounts of juice to about a cup or less a day and be encouraged to eat whole fruits instead.
Most juices are enriched with vitamin C and some are fortified with calcium. However, many nutrients such as water soluble vitamins, minerals, dietary fiber and phytochemicals are lost in the processing of juices. The skins, pulp and seeds of whole fruits contain much of their nutritional value.
Vegetable juices are excellent choices for beverages since they are nutrient dense. Some may want to choose the low-sodium varieties.
Remember to keep vegetable and fruit juices tightly closed and return to the refrigerator immediately after every use to preserve nutrients.
Analysis of diets in children and adolescents has shown that when flavored milk, yogurt, ice cream and pudding are chosen instead of sugar-sweetened beverages, vitamins and minerals increase and total fat, saturated fat and total sugars decrease. Even though these dairy foods have added sugar, they contain much less than the sugared beverages they are replacing.
The American Academy of Pediatrics recommends that the sale of sweetened drinks be restricted in schools. Some schools are already replacing sweetened beverages with water, milk and 100 percent juices.
For weight-conscious teens, the research that links milk with weight reduction as a part of a lower calorie diet, choosing low-fat and fat-free milk products might also help raise the intake of calcium — and when calcium intake increases so does the intake of other important vitamins and minerals.
Among teens, college students and adults, the gourmet coffee drinks they love can pack a fattening punch. Whether hot or iced, a large coffee combined with sugar, sugar syrups, whole milk or whipped cream can deliver up to 600 calories, 25 grams of fat and 100 grams of carbohydrates.
However, regular coffee, tea or cocoa are excellent beverage choices. Coffee, cocoa and black or green teas (even decaffeinated) contain phytochemicals that are not bound by adding milk.
Although sugared beverages are the ultimate empty-calorie food, many others are not far behind. Usually solid foods that are high in sugar are also high in fat — especially baked goods.
Other “junk” foods may be high in fat and salt. Some may combine processed flours or starch with sugar and/or salt. The common denominator is that all are high in calories and low in nutritional value.
Nonnutritive sweeteners provide a sweet taste without the calories and glycemic response of natural sugars. The Food and Drug Administration (FDA) has approved five nonnutritive sweeteners: saccharin, aspartame, acesulfame K, sucralose and neotame. Stevia is a natural nonnutritive sweetener that can be purchased as a dietary supplement, but is not FDA-approved.
Nonnutritive sweeteners are now usually blended in food and beverage systems and this keeps the intakes at acceptable levels. However, moderation is the key with nonnutritive sweeteners as with any other food. It also makes common sense to limit nonnutritive sweeteners in pregnancy and childhood.
The ultimate nutrient-dense foods are what some consider “power” foods. Power foods pack in the most nutrients per calorie. These include but are not limited to:
–Nuts — peanuts, almonds, walnuts, Brazil nuts, hazelnuts; seeds — sesame seeds, flaxseeds; olives and their oils
–Red, yellow, orange and blue fruits and vegetables such as apples, tomatoes, watermelon, berries, oranges, kiwifruit, sweet and chili peppers, grapes, sweet potatoes, pumpkin, mango, butternut squash
–Cruciferous and green vegetables such as spinach, kale, broccoli, watercress, greens, bok choy, brussels sprouts, cabbage, cauliflower
–Whole grains, especially oatmeal and quinoa
–Beans and peas such as black beans, kidney beans, yellow split peas, chickpeas, lentils
–Fatty fish such as sardines, wild salmon, tuna
–Onions, garlic and mushrooms
–Soy such as edamame, miso, temph
–Low-fat dairy, especially yogurt
Keep the majority of meals and snacks healthy. Keep those favorite empty-calorie treats the exception to the rule.
Editor’s Note — Pat Hart Terry, Ph.D., is chairman of the department of nutrition and dietetics at Samford University in Birmingham and a registered dietitian.
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