Five Characteristics of A Nutritious Diet. Six Classes of Nutrients in Foods. 10 Leading Causes of Death.
Food supplies energy and nutrients. Foremost among the nutrients is water. The energy-yielding nutrients are carbohydrates, fats (lipids), and protein. The regulator nutrients are vitamins and minerals. Food energy is measured in calories; food and nutrient quantities are often measured in grams.
The Energy-Yielding Nutrients
Foremost among the six classes of nutrients in foods is water, which is constantly lost from the body and must constantly be replaced. Of the four organic nutrients, three are energy-yielding nutrients, meaning that the body can use the energy they contain. The carbohydrates and fats (fats are also called lipids) are especially important energy-yielding nutrients. As for protein, it does double duty: it can yield energy, but it also provides materials that form structures and working parts of body tissues.
Vitamins and Minerals
The fifth and sixth classes of nutrients are the vitamins and the minerals. These provide no energy to the body. A few minerals serve as parts of body structures (calcium and phosphorus, for example, are major constituents of bone), but all vitamins and minerals act as regulators. As regulators, the vitamins and minerals assist in all body processes: digesting food; moving muscles; disposing of wastes; growing new tissues; healing wounds; obtaining energy from carbohydrate, fat, and protein; and participating in every other process necessary to maintain life.
The nutrients in food support growth, maintenance, and repair of the body. Deficiencies, excesses, and imbalances of energy and nutrients bring on the diseases of malnutrition.
The Diet and Health Connection
Your choice of diet profoundly affects your health, both today and in the future.
Only two common lifestyle habits are more influential: smoking and other tobacco use, and excessive drinking of alcohol.
Leading Causes of Death in U.S.
1. Heart disease 26.5%
2. Cancers 22.8%
3. Strokes 5.9%
4. Chronic lung disease 5.3%
5. Accidents 4.7%
6. Alzheimer’s disease 3.1%
7. Diabetes mellitus 2.9%
8. Pneumonia and influenza 2.6%
9. Kidney disease 1.8%
10. Blood infections 1.4%
Many older people suffer from debilitating conditions that could have been largely prevented had they known and applied the nutrition principles known today. The chronic diseases—heart disease, diabetes, some kinds of cancer, dental disease, and
adult bone loss—all have a connection to poor diet. These diseases cannot be prevented by a good diet alone; they are to some extent determined by a person’s genetic constitution, activities, and lifestyle. Within the range set by your genetic inheritance, however, the likelihood of developing these diseases is strongly influenced by your food choices.
Choice of diet influences long-term health within the range set by genetic inheritance. Nutrition has little influence on some diseases but strongly affects others.
What constitutes a nutritious diet?
A well-planned diet is adequate in nutrients, is balanced with regard to food types, offers food energy that matches energy expended in activity, is moderate in unwanted constituents, and offers a variety of nutritious foods.
How, Exactly, Can I Recognize a Nutritious Diet?
A nutritious diet has five characteristics.
First is adequacy: the foods provide enough of each essential nutrient, fiber, and energy.
Second is balance: the choices do not overemphasize one nutrient or food type at the expense of another.
Third is calorie control: the foods provide the amount of energy you need to maintain appropriate weight—not more, not less.
Fourth is moderation: the foods do not provide excess fat, salt, sugar, or other unwanted constituents.
Fifth is variety: the foods chosen differ from one day to the next.
In addition, to maintain a steady supply of nutrients, meals should occur with regular timing throughout the day.
Any nutrient could be used to demonstrate the importance of dietary adequacy. Iron provides a familiar example. It is an essential nutrient: you lose some every day, so you have to keep replacing it; and you can get it into your body only by eating foods that contain it. If you eat too few of the iron-containing foods, you can develop iron-deficiency anemia: with anemia you may feel weak, tired, cold, sad, and unenthusiastic; you may have frequent headaches; and you can do very little
muscular work without disabling fatigue. Some foods are rich in iron; others are notoriously poor. If you add iron-rich foods to your diet, you soon feel more energetic. Meat, fish, poultry, and legumes are in the iron-rich category, and an easy
way to obtain the needed iron is to include these foods in your diet regularly.
To appreciate the importance of dietary balance, consider a second essential nutrient, calcium. A diet lacking calcium causes poor bone development during the growing years and increases a person’s susceptibility to disabling bone loss in adult life. Most foods that are rich in iron are poor in calcium. Calcium’s richest food sources are milk and milk products, which happen to be extraordinarily poor iron sources. Clearly, to obtain enough of both iron and calcium, people have to balance their food choices among the types of foods that provide specific nutrients. Balancing the whole diet to provide enough but not too much of every one of the 40-odd nutrients the body needs for health requires considerable juggling, however. Food group plans that cluster rich sources of nutrients into food groups can help you to achieve dietary adequacy and balance because they recommend specific amounts of foods from each group. Balance among the food groups then becomes the goal.
Energy intakes should not exceed energy needs. Nicknamed calorie control, this diet characteristic ensures that energy intakes from food balance energy expenditures required for body functions and physical activity. Eating such a diet helps to
control body fat content and weight.
Intakes of certain food constituents such as fat, cholesterol, sugar, and salt should be limited for health’s sake. A major guideline for healthy people is to keep fat intake below 35 percent of total calories. Some people take this to mean that they must never indulge in a delicious beefsteak or hot-fudge sundae, but they are misinformed: moderation, not total abstinence, is the key. A steady diet of steak and ice cream might be harmful, but once a week as part of an other wise moderate diet plan, these foods may have little impact; as once-a-month treats, these foods would have practically no effect at all. Moderation also means that limits are necessary, even for desirable food constituents. For example, a certain amount of fiber in foods contributes to the health of the digestive system, but too much fiber leads to nutrient losses.
As for variety, nutrition scientists agree that people should not eat the same foods, even highly nutritious ones, day after day. One reason is that a varied diet is more likely to be adequate in nutrients. In addition, some less-well-known nutrients and phytochemicals could be important to health and some foods may be better sources of these than others. Another reason is that a monotonous diet may deliver large amounts of toxins or contaminants. Such undesirable compounds in one food are
diluted by all the other foods eaten with it and are diluted still further if the food is not eaten again for several days. Last, variety adds interest—trying new foods can be a source of pleasure.
A caution is in order. Any one of these dietary principles alone cannot ensure a healthful diet. For example, the most likely outcome of relying solely on variety could easily be a low-nutrient, high-calorie diet consisting of a variety of snack foods and nutrient-poor sweets. If you establish the habit of using all of the principles just described, you will find that choosing a healthful diet becomes as automatic as brushing your teeth or falling asleep. Establishing the A, B, C, M, V habit may take some effort, but the payoff in terms of improved health is overwhelming.