1.2: What Is Nutrition?
By the end of this section, you should be able to:
- 1.1.1 Define nutrition.
- 1.1.2 Identify key events in the history of nutrition.
A Basic Definition of Nutrition
Nutrition is the intake of food to meet the needs of the body. Accordingly, nutrients are substances found in foods and beverages that are essential for survival. Nurses must understand the components of nutrition and its impact on bodily functions to provide effective nursing care.
Several food-related concepts are fundamental to understanding how nutrition affects the body. The term food refers to edible substances made of protein, carbohydrates , fat, or other nutrients. Food is comprised of macronutrients and/or micronutrients. Macronutrients are water and energy-yielding nutrients (carbohydrates, fats, and proteins) needed in large amounts by the body. Micronutrients include vitamins and minerals. Food is the building block of the diet , which describes the quantity and quality of food and drinks consumed.
Nutrition in Foods
Understanding calories is essential to understanding how the body uses nutrients for fuel. Calories, which measure the amount of heat it takes to raise 1 kg of water by 1ºC, are used to indicate the amount of energy needed or ingested daily. Human bodies need calories to function, digest food, grow, and move. The 2020-2025 Dietary Guidelines issued jointly by the U.S. Department of Agriculture and the U.S. Department of Health and Human Services recommend adult women consume an estimated 1,600 to 2,400 calories daily and adult men 2,000 to 3,000 calories daily based on age and activity level (USDA & USHHS, 2020).
The number of calories found in food varies based on food type. Table 1.1 lists the number of calories found in macronutrients. Food preparation can modify the number of calories present. For example, a raw tomato has fewer calories than a fried tomato. Water is classified as a macronutrient. Although it serves a vital role, it does not provide energy to the body.
| Macronutrient | Calories per Gram | Recommended Daily Intake |
|---|---|---|
| Carbohydrate | 4 | 45–65% |
| Fat | 9 | 20–35% |
| Protein | 4 | 10–35% |
Counting calories is one way to determine if clients are consuming an appropriate amount of food to meet their needs. Calorie needs vary based upon client age, sex, and level of physical activity. Use this calorie calculator when working with clients to determine their individual caloric needs.
The History of Nutrition in the Provision of Client Care
Modern nutrition science advanced significantly during the 20th century (Mozaffarian, Rosenberg & Uauy, 2018). The identification of essential vitamins and minerals in the early 1900s launched the quest to identify and treat vitamin-deficient medical conditions such as beriberi. Subsequent nutritional discoveries led to the practice of fortifying certain foods to prevent deficiencies and setting the first recommended dietary allowances (RDAs).
During this same time frame, the federal government began to oversee and manage the food supply. In 1906, the Pure Food and Drugs Act was passed, which launched the federal regulation of foods by the agency later known as the U.S. Food and Drug Administration (FDA, 2018). The FDA was initially established to oversee how food was prepared for consumers. This became necessary because as more people moved from rural to urban areas, they depended on others to grow and produce the food they needed.
In 1938, the Food, Drug, and Cosmetic Act (FDCA) of 1938 was passed, significantly enhancing labeling requirements. The FDCA required food labels to include the product’s recognizable name and standardized information related to the identity, quality, and amount in the container (Lam & Patel, 2022).
Later, in the second half of the 20th century, the focus of nutrition shifted toward nutrition and its relationship to health (USDA & USHHS, n.d.). In 1977, the first-ever federal guidance related to diet quality was published in Dietary Goals for the United States . These goals were intended to improve the typical American diet to decrease the incidence of heart disease. The development of these goals prompted pushback from some members of the food industry. For example, the goals originally recommended to reduce the intake of red meat in the diet. However, groups such as the National Cattlemen’s Beef Association opposed this recommendation since it would negatively affect the beef industry. Consequently, the language in the federal guidelines was changed from minimizing red meat to selecting foods that will minimize saturated fat intake (Stillerman, 2019).
Continuing this new shift in perspective, in 1982 the Committee on Diet, Nutrition, and Cancer, National Research Council presented their findings on the relationship between diet and cancer. These findings served as a foundation to promote nutritional factors and dietary needs that decrease the incidence of cancer. Not only did the report discuss foods linked to the potential development of cancer, but it also identified foods that supported cancer prevention . This study specifically mentioned macronutrients and micronutrients found in the diet and their impact on cancer development and/or prevention. This introduction of macronutrients and micronutrients to the public facilitated several agencies to take active roles in promoting dietary agendas. For example, the Nutrition Labeling and Education Act of 1990 prompted all food packaging entities to label foods with nutritional information and serving sizes.
Through the years, visual displays of government food guides have been modified to reflect the changing perspectives. The first guide, released in the 1940s, divided foods into seven groups and encouraged people to eat foods from all groups as well as food not included in the seven groups without specifying amounts. The widely recognized Food Guide Pyramid was first introduced in the 1990s and underwent several revisions until it was replaced by MyPlate in 2011 (Davis & Saltos, n.d.; USDA, 2021). The most recent dietary guidelines for Americans, 2020–2025, uses the original MyPlate visual guide to recommend small, simple changes to improve diet quality.
Nutrition for Wellness
The Global Wellness Institute defines wellness as pursuing activities, choices, and lifestyles leading to holistic health. Multiple factors influence a person’s health, including nutrition. Good nutrition is essential for keeping the population healthy (CDC, 2021).
Origin of Nutrition Related to Wellness
The ancient Greek physician who influenced much of modern medicine, Hippocrates, is credited with saying, “Let food be thy medicine and medicine be thy food” (King, 2019). This appears to be one of the earliest statements acknowledging the role of nutrition in maintaining health. In 1948, the World Health Organization (WHO) defined health as “a state of complete physical, mental and social well-being and not merely the absence of disease or infirmity” (WHO, n.d.). This definition reflected a growing emphasis on a holistic perspective of health.
Weight Versus Body Mass Index
Several measurements are recognized and used to assess a person’s nutritional status and identify individuals at risk for illness or disease. These indicators go beyond simply measuring a person’s weight to assess body composition and weight distribution. Body mass index (BMI) is a formula that calculates the ratio of weight and height to classify individuals as underweight, healthy weight, overweight, or obese. The waist-to-hip ratio (WHR) calculates the ratio of the circumferences of the waist to the hip. Evidence has shown that individuals with excess weight around their midsection may be at higher risk for certain health conditions. These assessments can be done at home or with a health care provider to gain important information about an individual’s dietary-related health.
Recently, the routine use of BMI as a lone indicator of obesity has been scrutinized as a result of research that shows BMI may not be a reliable indicator for diverse populations. The American Medical Association (AMA) has adopted a new policy clarifying the use of BMI as one means of identifying obesity. The policy states that BMI should not be used exclusively to identify obesity; instead, it should be used in conjunction with other assessment tools. The policy acknowledges the BMI assessment is based on data from non-Hispanic White populations and does not consider differences in body shape and composition across different race/ethnic groups, sexes, or age groups (AMA, 2023).
BMI is a screening tool used to identify clients who are overweight or obese. Considering the recent policy change by the AMA, nurses should stay abreast of new research to determine how to incorporate BMI measurements when working with diverse client populations. BMI does not measure body fat directly but correlates with other more direct measures of body fat such as skinfold thickness measurements. High BMI can be correlated with obesity-linked adverse health outcomes. To determine BMI, input the client’s height and weight into the Adult BMI Calculator . Use Table 1.2 to interpret the results.
| BMI | Weight Status |
|---|---|
| < 18.5 | Underweight |
| 18.5 to < 25 | Heathy weight |
| 25.0 to < 30 | Overweight |
| 30.0 to < 35.0 | Class 1 obesity |
| 35.0 to < 40.0 | Class 2 obesity |
| > 40.0 | Class 3 obesity |
Clients may be self-conscious about having body measurements taken. Provide privacy for your client when taking these measurements. To determine WHR , with the client standing upright, use a tape measure to measure the distance around the smallest part of the client’s waist (waist circumference) and then the largest part of the client’s hip (hip circumference). Then divide the waist circumference by the hip circumference or use this online calculator to determine the WHR. The result is determined using Table 1.3.
| Health Risk | Women | Men |
|---|---|---|
| Low | ≤ 0.80 | ≤ 0.95 |
| Moderate | 0.81–0.85 | 0.96–1.0 |
| High | ≥ 0.86 | > 1.0 |
Health Promotion
Healthy People 2030 is a framework of U.S. public health objectives designed to improve the health and well-being of the population (USHHS, ODPHP, n.d.). Since its initial release in 1980, it has been updated each decade to shape health promotion and disease prevention strategies in the U.S. (CDC, 2023). In terms of nutrition, Healthy People 2030 aims to help people get the recommended amounts of healthy foods to reduce their risk for long-term diseases and improve their health (USHHS, ODPHP, n.d.)