"Nutrition is the science of food and its relation to health." We all are, or should be, vitally interested in promoting or protecting our own health, since upon it depends our happiness, capacity for rewarding work, and even our length of life. The rapidly developing science of nutrition has accumulated a mass of facts about what constitutes the best type of diet and proofs that food may be used as a tool for building strong bodies. Some knowledge of the basic facts of nutrition are helpful to anyone, while a more detailed and scientific background of knowledge is essential for those who have the responsibility of feeding others and participating in health education - that is, home-makers, nurses, doctors, hospital dietitians, teachers and extension workers in the field of nutrition, public health workers, and managers of public eating places and school lunch-rooms.
The people of the United States have the most plentiful supply and widest variety of foods available to any nation. Food selection is often not wise, and the difficulty in obtaining proper choices of foods for adequate diets is increased by low incomes in about one-fifth of our population. While it is true that children of the present generation grow faster and taller and weigh more than did those of comparable ages 50 years ago, middle-aged and older people often suffer from chronic disease conditions which may well be related to long-time consumption of less than optimal diets. Many of our health problems stem from overeating or from eating too freely of certain types of food (sugar, starchy foods, and fats); overweight and the diseases that are often associate with it (diabetes, high blood pressure, heart disease, etc.) are increasingly common among young adults, as well as older people.
Moreover, although proper nutrition provides an essential basis for health, good health also depends on many other factors. Factors of heredity, disease, environment, stress, and emotional instability may counter-balance the effects of a good diet.
Instinctive Selection of Foods Does Not Always Lead to Good Nutrition
It is true that in many parts of the world people who know little or nothing of the science of nutrition have subsisted for generations on diets that maintained strong bodies. Sometimes, with even a limited variety of foods, those available were such that all the requirements for good nutrition were provided. Other primitive peoples were not so fortunate; either the food supply was inadequate or the cultural habits prompted selection of food that made an improperly balanced diet which lacked some factors necessary for growth and health. The peoples of tribes farther north, who used unmilled millet or wheat along with goats milk and butter, had splendid physiques and enough stamina to make good soldiers. In remote sections of the Himalaya Mountains races were found whose frugal diet was made up mostly of apricots, vegetables, and goats milk, with meat eaten only on feast days; these peoples were unusually strong, healthy, and long-lived.
More recently, there have been many suggestions that diet may be correlated, not only with physical stamina, but also with mental alertness and emotional stability. In extensive studies on undernutrition, Keys showed that changes in behavior and work capacity result from prolonged underfeeding.
Things That Stand in the Way of Improving Dietary Habits
Factors that militate against improvement of nutritional status through changing food habits may be briefly summarized as
- Ignorance and prejudice
- Cultural habits
- Fads and false advertising
The food habits of later life often stem from prejudices acquired in childhood, either from parental examples or from childish whims that are indulged. Only education that explains why foods selected should include those needed to supply all the essentials for an adequate diet and a belief that better choice of foods will lead to more buoyant health will provide motivation to change old food habits for new ones. This is especially true when food habits in the home are based on cultural or religious practice. However, such deep-rooted objections can often be overcome by suggestions that larger amounts of certain liked or permitted foods should be taken or that new foods may be cooked in well liked or familiar ways. Reducing fads and advertising literature that sponsors them may also induce a person to take unbalanced diets which furnish too little of certain nutritive essentials, and the advertising "boosting" of some types of food may persuade one to use such foods too largely and depend too little on other needed foods.
Complacency is also a strong factor working against change of food habits. Unless a person has a vision of the greater vitality to be attained by improving his food habits, he is apt to believe that he is well enough off as he is. The average consumption of various foods in the protective foods class has been decidedly increased, but of course many individuals still eat far less than optimum amount of these foods. Babies and young children grow faster and have sturdier bodies than before the knowledge of nutritional needs was as well understood as it is now.