human nutrition assignment | Applied Sciences homework help
- A portion of food is defined as a stan-dard serving size. T/F See page 71 for the answers.
Tools for Healthy Eating M02_BLAK8260_04_SE_C02.indd 39 12/1/17 10:08 PM 40 Chapter 2 | Tools for Healthy Eating What Are the Key Principles of Healthy Eating? LO 2.1 Describe the key principles of healthy eating. Healthy eating means you need to balance, vary, and moderate your nutrient intake. In addition, a healthy diet includes foods that are high in nutrient density and low in energy density. Healthy Eating Means Balance between Food Groups A balanced diet includes healthy proportions of all nutrients and is adequate in energy. A diet that lacks balance can cause undernutrition. For instance, a student subsisting largely on bread, bagels, muffins, crackers, chips, and cookies might be eating too much carbohydrate and fat but too little protein, vitamins, and minerals. If the diet lacks a par- ticular nutrient, such as protein, over time the body suffers from malnutrition. A meal that contains foods from the grain, vegetable, fruit, meat, and dairy groups, such as a lunch of a turkey-and-cheese wrap with lettuce and tomato plus an apple, provides the proper proportion of foods from each of the food groups. This balancing act prevents overnutrition of a specific nutrient, such as fat,1 or too many kilocalories, which can lead to overweight and obesity. Consuming adequate amounts of all essential nutrients is key to avoiding nutrient deficiencies and, in many cases, chronic disease. balance Diet principle of providing the correct proportion of nutrients to maintain health and prevent disease. vary Diet principle of consuming a mixture of different food groups and foods within each group. moderate Diet principle of providing reason- able but not excessive amounts of foods and nutrients. nutrient density Measurement of the nutri- ents in a food compared with the kilocalorie content; nutrient-dense foods are high in nutri- ents and low in kilocalories. energy density Measurement of the kilo- calories in a food compared with the weight (grams) of the food. A meal that contains foods from every food group is part of a bal- anced, healthy diet. Many Americans believe that to eat a healthful diet means giving up their favorite foods. Nothing could be farther from the truth! With a little planning, you can still occasionally eat almost any food even if it contains added sugars and fat and is high in kilocalories. All it takes are the right tools to balance those higher kilocalorie foods with more nutritious choices each day. The good news is that a number of tools are available to help you achieve a healthful, balanced eat- ing plan. This chapter explains how to use these tools in a consistent manner that over time will lead to better eating habits. Let’s begin with a discussion of what healthy eating is. M02_BLAK8260_04_SE_C02.indd 40 12/1/17 10:08 PM What Are the Key Principles of Healthy Eating? 41 Healthy Eating Means Consuming a Variety of Foods Choosing a variety of foods improves the quality of the diet because the more var- ied the food choices, the better the chance of consuming adequate amounts of all the essential nutrients.2 Even within one food group, the nutrient composition of foods can vary dramatically. For example, while broccoli is a good source of folate, it has less than half the vitamin A of a carrot. Similarly, if the only fruit you eat is bananas, your diet would include an excellent source of potassium, but could be low in vitamin C. Because no single food or food group contains everything you need to be healthy, you should choose a variety of foods from within each food group and among food groups each day. This is the basic principle of the Fruits & Veggies—More Matters campaign developed by the Produce for Better Health Foundation and the Centers for Disease Control and Prevention.3 This campaign promotes eating a vari- ety of colorful fruits and vegetables—which are rich in vitamins, minerals, fiber, and phytochemicals—each day to help reduce the risk of cancer and heart disease and slow the effects of aging. Healthy Eating Means Moderate Intake of All Foods According to many registered dietitian nutritionists (RDNs), “there are no good or bad foods, just good or bad habits.” What they mean is that all foods—even less nutritious foods—can be part of a healthy diet, as long as they are consumed in moderation. Foods such as sweets and fried or packaged snack foods should be eaten only in small amounts to avoid consuming too much sugar and saturated fat, as well as too many kilocalories. Finally, these foods can displace more nutritious choices, resulting in a diet that lacks essential nutrients. Even some healthy foods, such as nutrient-dense nuts, can be high in kilocalories and should be consumed in moderation. Healthy eating doesn’t mean you can’t enjoy your favorite foods. It simply means eating those foods in moderation by lim- iting the portion size and number of servings you eat. Many people overestimate the appropriate portion sizes of foods. An entire body of research is devoted to studying factors that affect how much we put on our plates. The important point is that, in general, we tend to consume portions larger than necessary to meet our kilocalorie needs. See the Health Connection on pages 65–67 for examples of visuals you can use to estimate portion sizes. For suggestions on eating a balanced, varied, and moderate diet, see the Table Tips. Healthy Eating Includes Nutrient-Dense Foods Healthy eating also means choosing foods that are nutrient dense. Nutrient-dense foods are high in nutrients, such as vitamins and minerals, but low in energy (kilocalories), pro- viding more nutrients per kilocalorie (and in each bite) than less nutrient-dense foods.4 Fresh fruits and vegetables, for example, are nutrient dense because they are high in B vitamins, vitamin C, and minerals such as calcium and magnesium, as well as dietary fiber, while usually providing fewer than 60 kilocalories per serving. Nutrient-dense foods are also low in saturated fat and added sugars. To illustrate this concept, compare the nutrient density of two versions of the same food: a baked potato and potato chips (Figure 2.1). Although a medium baked potato and one ounce of potato chips have about the same number of kilocalories, the baked potato provides much higher amounts of vitamins and minerals than the deep-fried chips. Though many foods, such as vegetables, are clearly nutrient dense, and other foods, such as candy, are clearly not, some foods do not fit neatly into these two categories. Items such as dried fruits, nuts, peanut butter, and avocados are higher in kilocalories, but they are also excellent sources of important nutrients, including polyunsaturated fatty acids, calcium, and iron. Other foods, such as whole milk or yogurt, are higher portion Quantity of a food usually eaten at one sitting. Choosing a variety of nutrient-dense foods you enjoy is a key to eating a healthy diet.
TABLE TIPS
Tips for a Balanced, Varied, and Moderate Diet Keep healthy snacks such as whole- grain crackers in your dorm room and combine them with protein-rich peanut butter or low-fat yogurt. Pop a snack-pack size of light micro- wave popcorn for a portion-controlled whole-grain snack while you study. Adopt a multicolor code to guide your food choices. Add tomato slices and a low-fat cheese slice to your whole-grain sandwich and carrots to your tossed green salad to ensure that your choices are adequate and varied. Pack your own snack-sized portions of dried fruit, trail mix, whole-wheat crack- ers, baby carrots, or salt-free pretzels to carry in your backpack. Snack-sized bags of nuts and seeds are a nutri- tious way to help you avoid the vending machine and eat smaller, more moder- ate portions. Keep your sweets to no more than about 100 kilocalories a day. M02_BLAK8260_04_SE_C02.indd 41 12/1/17 10:08 PM 42 Chapter 2 | Tools for Healthy Eating in saturated fat and kilocalories than their nonfat or low-fat counterparts, but still pro- vide significant amounts of calcium, riboflavin, vitamins A and D, and protein. Some foods, such as fruit-flavored yogurt and some fortified cereals, contain added sugars in addition to several essential nutrients. Do you think these foods can be considered nutrient dense? In all of these scenarios, the answer is yes. Whereas nutrient dense usually means high in nutrients and low in energy, foods that are high in nutrients and high in energy can also be considered nutrient dense. The key is to be aware of the extra kilocalories and make up for them elsewhere in the diet. If you don’t like skim milk and won’t drink it, but do enjoy the taste of whole milk, then drinking whole milk is a more healthy choice than drinking soda. Healthy Eating Includes Low-Energy-Dense Foods In contrast to nutrient density, energy density refers to foods that are high in energy but low in weight or volume, such as that potato chip. A serving of deep-fried chips weighs much less than a plain baked potato, but is considerably higher in kilocalories. Therefore, the chip contains more energy per gram. A big, leafy green salad, on the other hand, is large in volume but low in energy density, because of its high water content. Most high-fat foods are considered energy dense.5 This is because fat has 9 kilocalories per gram and is thus 2.25 times more energy dense than either carbohy- drates or protein at 4 kilocalories per gram. Individuals who choose low-energy-dense foods will generally have diets that are lower in fat and higher in nutrient content. Eating a low-energy-dense diet can sometimes be the key to weight loss. Recent studies have found that leaner individuals ate more low-energy-dense foods and fewer kilocalories, while consuming a greater volume of food, compared with their obese counterparts.6 Even modest changes in dietary intake may promote and help maintain weight loss7 over time.8 One reason for this may be that eating higher-volume, lower- energy foods means larger portions for the same number of kilocalories. Other reasons may include improved satiety and appetite control.9 In other words, low-energy foods will “fill you up before they fill you out.” If you are trying to maintain your current weight, or lose weight, you are probably on a limited energy budget and need to choose foods that are nutrient dense and low in kilocalories. Use the guide in Table 2.1 to help stretch your energy budget while con- suming the most nutrient-dense foods. satiety Feeling of satiation, or “fullness,” after a meal before hunger sets in again. ▲ Figure 2.1 Which Is the Healthier Way to Enjoy Potatoes? Whereas one ounce of potato chips and one medium baked potato have similar kilocalories, their nutrient content is worlds apart. A baked potato contains more folate, potassium, and vitamin C, and fewer fat kilocalories, than its fried counterpart. The baked potato is therefore more nutrient dense than potato chips. * Note: Based on the percentage of the DRI for 19- to -50-year-old males. All these percentages apply to females in the same age range, except for vitamin C. Females have lower vitamin C needs than males, so a baked potato provides over 20 percent of the DRI of this vitamin for women. 100 20 40 60 80 Pe rc en t D
R I*
Potato chips, 1 oz Baked potato, medium Vitamin CPotassiumFolate M02_BLAK8260_04_SE_C02.indd 42 12/1/17 10:08 PM What Are the Key Principles of Healthy Eating? 43 Many Resources Are Available for Planning a Healthy Diet Do you think all this advice for planning a healthy diet is hard to keep straight? If so, you’re not alone. Fortunately, several tools can help you avoid both under- and overnutri- tion, including:
- The Dietary Reference Intakes (DRIs), which provide recommendations regarding your nutrient needs
- The Dietary Guidelines for Americans, which provide broad dietary and lifestyle advice • MyPlate, part of the ChooseMyPlate.gov Web-based initiative, which is designed
to help you eat healthfully and implement the recommendations in the DRIs and the advice in the Dietary Guidelines
- The exchange system, which groups foods according to their macronutrient content, thus making it easier to plan meals
- The Nutrition Facts panel on food labels, which contains the percent Daily Values, and which can help you decide which foods to buy
Together, these tools help you plan a balanced, moderate, and varied diet that meets your nutrient and health needs. Table 2.2 compares these tools, and the following text sec- tions discuss each in more detail. Foods Energy Density Are They an Energy Bargain? Soups Fruits Vegetables 0.0–0.6 kcal/g Great Energy Bargain: Eat as much of these low-energy-density foods as you want; however, take care that soups don’t contain too much sodium and are made with broth rather than cream. Starchy fruits and vegetables Lean meats Beans and legumes 0.6–1.5 kcal/g Good Energy Bargain: Consume healthy portions of these foods. Cheese Salad dressings Snack foods 1.5–4.0 kcal/g More Expensive Choices: These foods should be chosen carefully and con- sumed in moderation. Chocolates Chips Candy Deep-fat fried foods Desserts 4.0–9.0 kcal/g Very Expensive Choices: Eat less of these foods and be aware of the portion size to avoid overconsuming kilocalories. Source: Adapted from B. Rolls. 2012. The Ultimate Volumetrics Diet: Smart, Simple, Science-Based Strategies for Losing Weight and Keeping It Off. New York: HarperCollins. TABLE 2.1 Bargain Shopping on an Energy Budget DRIs Dietary Guidelines for Americans MyPlate Nutrition Facts Panel Exchange Lists for Healthy Eating What Are They? Specific reference values for each nutrient by age and gender. Guidelines for nutri- tion and health that are informed by the most cur- rent scientific evidence, updated every 5 years. A representational icon that depicts five food groups using the familiar mealtime visual of a place setting. Contains impor- tant nutrition infor- mation to be used to compare food products. Lists that are orga- nized into food groups by their carbohydrate, protein, fat, and kilo- calorie contents. How Do They Guide You in Healthy Eating? DRIs provide rec- ommendations to prevent malnutrition and chronic diseases for each nutrient. The upper level is designed to prevent overnutri- tion or toxicity. The Dietary Guidelines emphasize following a healthy, plant-based diet to maintain a healthy weight and reduce the risk for chronic disease. MyPlate is the focal point for the Web-based ChooseMyPlate.gov initiative, which provides information to build a healthy diet based on the Dietary Guidelines for Americans. You can use the Nutrition Facts panel to compare the nutrient den- sity of foods. It’s easy to plan healthy menus with a variety of foods. The exchanges are based on specific food por- tion sizes plus various fat levels in foods. TABLE 2.2 Putting It All Together: Tools for Healthy Eating (continued) M02_BLAK8260_04_SE_C02.indd 43 12/1/17 10:08 PM 44 Chapter 2 | Tools for Healthy Eating LO 2.1: THE TAKE-HOME MESSAGE Healthy eating emphasizes con- suming the right amount of food from a variety of food groups to provide an adequate intake of nutrients and a moderate level of energy. Choosing nutrient- dense and low-energy-dense foods ensures a diet high in nutrient content and low enough in energy to prevent weight gain. A variety of tools are available to help individuals make healthy choices. What Are the Dietary Reference Intakes? LO 2.2 Distinguish between the Dietary Reference Intake terms EAR, AI, RDA, UL, and AMDR. The Dietary Reference Intakes (DRIs) are issued by the Food and Nutrition Board (FNB) of the National Academy of Medicine. They identify the amounts of each nutrient that people in a specific life stage need to consume to maintain good health, prevent chronic diseases, and avoid unhealthy excesses.10 The recommendations are grouped according to life stage—such as childhood, older age, or pregnancy—because nutrient requirements differ according to these stages. A teenager may need more of a specific nutrient than a 55-year-old (and vice versa) and women need more of certain nutrients during pregnancy and lactation. Many of the recommendations also differ by gender. Males and females vary in some of their nutrient requirements because of differ- ences in their anatomy and physiology.11 The National Academy of Medicine periodically organizes committees of U.S. and Canadian scientists and health experts to update the DRIs to reflect the latest scientific research. Since the 1940s, the DRIs have been updated 10 times. In the 1990s, nutrition researchers identified expanded roles for many nutrients. Though nutrient deficiencies were still an important issue, research suggested that higher amounts of some nutrients could play a role in disease prevention. Also, as consumers began using more dietary sup- plements and fortified foods, committee members grew concerned that excessive con- sumption of some nutrients might be as unhealthy as, or even more dangerous than, not consuming enough. Hence, the FNB convened a variety of committees between 1997 and 2004 to take on the enormous task of reviewing the research on vitamins, minerals, carbohydrates, fats, protein, water, and other substances such as fiber and developing the current DRI reference values. The DRIs are continually updated as research evolves. Dietary Reference Intakes (DRIs) Refer- ence values for nutrients developed by the Food and Nutrition Board of the National Academy of Medicine, used to plan and evaluate the diets of healthy people in the United States and Canada. It includes the Estimated Average Requirement (EAR), the Recommended Dietary Allowance (RDA), the Adequate Intake (AI), and the Tolerable Upper Intake Level (UL). nutrient requirements Amounts of specific nutrients needed to prevent malnutrition or deficiency; reflected in the DRIs. DRIs Dietary Guidelines for Americans MyPlate Nutrition Facts Panel Exchange Lists for Healthy Eating What Are They Made Up Of? EARs, RDAs, AIs, ULs, and AMDRs Key messages emphasize healthy eating patterns, as well as limiting intake of added sugars, satu- rated fats, sodium, cho- lesterol, and caffeine. Recommendations are made for physical activ- ity as well as five food groups, plus oils: