Introduction to Nutrition

How many kilocalories are in a meal that contains 100 grams of carbohydrate, 20 grams of protein, and 10 grams of fat?

> 570 kilocalories There are 570 kilocalories in a meal that contains 100 grams of carbohydrate, 20 grams of protein, and 10 grams of fat. The number of kilocalories in this meal can be determined based on (1) the amount (weight in grams) of carbohydrates, protein, and fat in the meal and (2) the number of kilocalories per gram of that nutrient. Carbohydrates and protein provide 4 kilocalories per gram, and fats provide 9 kilocalories per gram. To find out the total kilocalories provided by each macronutrient, multiply the total grams of the each nutrient by the number of kilocalories per gram of that nutrient: 100 grams carbohydrates × 4 kilocalories = 400 kilocalories; 20 grams protein × 4 kilocalories = 80 kilocalories; 10 grams fat × 9 kilocalories = 90 kilocalories. Next, add the amount of kilocalories of each macronutrient portion of the meal to calculate the total kilocalories in the meal: 400 kilocalories of carbohydrates + 80 kilocalories of protein + 90 kilocalories of fat = 570 kilocalories.

What is meant by the term scientific method?

> A stepwise process used by scientists to generate sound research findings The scientific method is a stepwise process used by scientists to generate sound research findings. In the first step of the scientific method, scientists observe something in the natural world and ask questions. In the second step of the scientific method, scientists come up with an idea (or hypothesis) based on their observations. To confirm this hypothesis, scientists proceed to the next step in the scientific method, which is to conduct an experiment. The next step in the scientific method involves sharing these findings with the scientific community. As more and more studies are done that confirm these findings, a theory is developed. Once a theory has been developed and supported by subsequent experiments, a consensus is reached in the scientific community. A consensus is the opinion of a group of experts based on a collection of information. The entire process can take years to complete. Calculating the number of calories in a food is a known problem that can be easily solved using nutrient data and arithmetic. The calculation does not involve generating a hypothesis, testing, or doing additional studies to prove a theory.

Which of the following is the most credible person to turn to for accurate nutrition

> Registered Dietitian Nutritionist (RDN) For accurate nutrition advice, turn to a registered dietitian nutritionist (RDN). An RDN is a health professional who has completed at least a bachelor's degree in nutrition from an accredited university or college in the United States; completed a supervised practice; and passed an exam administered by the Commission on Dietetic Registration, the credentialing agency for the Academy of Nutrition and Dietetics. RDNs have an understanding of medical nutrition therapy, which is an integration of nutrition counseling and dietary changes based on an individual's medical history and current health needs to improve that person's health. RDNs work with their patients to make dietary changes that can help prevent diseases such as heart disease, diabetes, stroke, and obesity. RDNs must participate in continuing professional education in order to remain current in the fast-changing world of nutrition, medicine, and health and maintain their registration. An RN is a health professional who has graduated from a state-approved nursing program, has passed a national exam, and is licensed by a state to care for patients. A certified nutritionist is not the same as an RDN. Nutritionist is a generic term with no recognized legal or professional meaning. Some people may call themselves nutritionists without having any credible training in nutrition. Many medical doctors (MDs) refer their patients to RDNs for nutrition advice and guidance based on their diagnoses.

During the past three decades in the United States, the prevalence of obesity has _____ .

> dramatically increased During the past three decades in the United States, the prevalence of obesity has dramatically increased. Thirty years ago, a majority of U.S. states (34 out of 50) had an obesity rate of 10% to 14%, and no state had an obesity rate greater than 19%. In 2010, the last year in which there was a significant increase in rates, 38 states had an obesity rate of 25% or higher. Although the U.S. obesity rate has stabilized in recent years, it still represents a dramatic increase from decades past.

The energy-yielding macronutrient that provides the most kilocalories per gram is:

> fat The energy-yielding macronutrient that provides the most kilocalories per gram is fat. The macronutrients—carbohydrates, fats (lipids), and proteins—are the energy-providing nutrients because they contain calories. Fats provide 9 kilocalories per gram. Carbohydrates and protein provide 4 kilocalories per gram. Alcohol is not an essential nutrient; even though it provides energy in the form of kilocalories, the body does not need it to function.

Plant-derived chemicals that are not nutrients but may have health-promoting properties are _______.

> phytochemicals Phytochemicals are naturally occurring nonnutritive compounds found in plants. They are thought to have health-promoting properties for humans who consume them. Eating an abundance of phytochemical-rich foods has been shown to reduce the risk for a number of diseases as well as age-related functional decline. Vitamins, minerals, and carbohydrates are nutrients. Moreover, certain vitamins, minerals, and carbohydrates are available from animal-based, as well as plant-based, foods. Probiotics are living microorganisms found in fermented dairy and other foods and thought to have health-promoting properties.

Which of the following nutrients provides energy?

> protein Protein is the only nutrient on this list that provides energy (kilocalories). Foods are composed of many chemical substances, some of which are critical to our growth and function. These latter chemicals are referred to as macronutrients. Only three nutrients provide energy: carbohydrates, fats, and proteins. Vitamin B6 does not provide energy. Vitamins are organic compounds that help regulate our bodies' functions. Contrary to popular belief, vitamins do not provide energy. However, they are essential to energy metabolism. Calcium is a mineral, and minerals do not provide energy. However, calcium, like all minerals, is essential to many important functions. Moreover, calcium is the major mineral component of our bones. Water is a nutrient critical to the body's most essential functions. However, it does not provide energy.

Which of the following must be considered when assessing whether or not the nutrition and health information on a website is accurate and current?

> who wrote it, when it was written, and when it was last updated To assess whether or not the nutrition and health information on a website is accurate and current, it's important to know who wrote it, when it was written, and when it was last updated. The National Institutes of Health has developed 10 questions to consider when viewing a nutrition- or health-related website, including (1) Who runs and pays for the site?; (2) What is the source of information?; and (3) How current is the information? Is the author a qualified nutrition expert, or did she or he interview qualified individuals? If the author obtained information from another source, was that source cited? Credible websites are willing to show their credentials. Finding out who's paying for a particular site will also reveal something about the reliability of its content. Websites sponsored by the government (with URLs ending in .gov) or an academic institution (.edu) are more reliable than many commercial websites (.com or .net). Some commercial websites, such as WebMD, carry articles that may be reliable if they are written by credible health professionals, but other websites may be promoting information to suit a company's own purposes. The website content may be biased based on the funding source. Once a website is on the Internet, it will stay there until someone removes it. Consequently, the information it contains may not be the most up to date. A good rule of thumb is to make sure the website has been published or updated within the year.

How many kilocalories are provided by 10 grams of carbohydrate?

> 40 kilocalories Ten grams of carbohydrate provide 40 kilocalories. To calculate the total kilocalories in an amount of a macronutrient, multiply the total grams of the energy-yielding nutrient by the number of kilocalories per gram of that nutrient. Carbohydrates and protein provide 4 kilocalories per gram, and fats provide 9 calories per gram. Therefore, the equation to find the total calories in 10 grams of carbohydrates is: 10 grams carbohydrates × 4 calories = 40 calories.

Which of the following best defines metabolism?

> The chemical reactions that occur within body cells. The term metabolism refers to all of the chemical reactions that occur within body cells, including reactions that result in the breakdown of larger molecules into smaller units, and those that join smaller units together to form larger molecules. Energy metabolism refers specifically to the chemical reactions by which cells convert carbohydrates, fats, and proteins into energy. The conversion of body fat stores to energy, the digestion of food and absorption of nutrients, and the assembly of functional chemicals and structural compounds are all examples of metabolism.

Which of the following is an objective of Healthy People 2020?

> To increase the proportion of U.S. adults who are at a healthy weight An objective of Healthy People 2020 is to increase the proportion of U.S. adults who are at a healthy weight. Another Healthy People objective is to increase—not reduce—the proportion of U.S. adults who engage in leisure-time physical activity. The Healthy People objectives apply to the U.S. population as a whole, not to a specific state, such as New Jersey, nor are the obejctives international in scope.

Which of the following is an example of an organic compound?

> carbohydrates An organic compound is a substance made up of carbon and hydrogen along with one or more other elements. Carbohydrates are organic compounds because they contain carbon, hydrogen, and oxygen. Fats, proteins, and all vitamins are also organic compounds. Water does not contain carbon and is not organic. Minerals are discrete elements, not compounds. The mineral iron, for example, contains only iron. Oxygen is also an element, not a compound.

Nutrients are divided into _____ classes.

> six Nutrients are divided into six classes: carbohydrates, fats (lipids), proteins, vitamins, minerals, and water. These nutrients work together to provide energy, growth, and maintenance, and to regulate numerous body processes. Three of the six classes of nutrients—carbohydrates, fats (part of the larger class of lipids), and protein—provide energy in the form of kilocalories. Vitamins, minerals, and water help regulate many body processes, including metabolism. In fact, water is found in all foods and beverages and is so vital to life that people can't live without it for more than a few days.

Which of the following is NOT an overarching goal of Healthy People 2020?

> Increase the use of sustainable resources to reduce global warming Increasing the use of sustainable resources to reduce global warming is NOT an overarching goal of Healthy People 2020. Healthy People 2020 is a set of disease prevention and health promotion objectives for Americans to meet during the second decade of the new millennium. The U.S. surgeon general has issued these nationwide health improvement objectives since 1979. Healthy People 2020 focuses on several overarching goals: Attain high-quality, longer lives free of preventable disease, disability, injury, and premature death. Achieve health equity, eliminate disparities, and improve the health of all groups. Create social and physical environments that promote good health for all. Promote quality of life, healthy development, and healthy behaviors across every stage of life.

Which of the following is a primary way in which proteins are used in the body?

> To build and maintain tissues and organs A primary way proteins are used in the body is to build and maintain tissues and organs. Fats help cushion organs and act as insulation under the skin. Carbohydrates provide an immediate source of energy during intense physical activity. The body can use proteins for energy, but this is not their primary role. Finally, minerals such as calcium, magnesium, and phosphorus contribute to the mineralization of bone.

The majority of an individual's daily kilocalories should come from __________.

> carbohydrates The majority of an individual's daily kilocalories should come from carbohydrates. Carbohydrates supply the simple sugar, called glucose, that cells use as the major energy source to fuel the body. Fats contain kilocalories and are another fuel source for the body, but they shouldn't be the main source of energy in a person's diet. Minerals and vitamins do not provide kilocalories. Water does not provide energy or kilocalories.

The research design in which neither the scientists nor the subjects can distinguish between the experimental group and the control group is called:

> double-blind, placebo controlled The research design in which neither the scientists nor the subjects can distinguish between the experimental group and the control group is called double-blind, placebo controlled. A double-blind, placebo-controlled study is considered the gold standard of research because all of the factors that might influence the study results are kept the same for each group of subjects, and neither the subjects nor the researchers are biased as they don't know which group has received which treatment. Peer-reviewed research involves fellow scientists (peers) reviewing studies to assess if they are accurate and sound before they are published. Epidemiological research is a type of research that looks at populations of people; it is often observational. Placebo research involves giving a placebo, or "sugar pill," that has no impact on the individual's health when ingested.

Which of these nutrition-related diseases is the leading cause of death in the United States?

> heart disease Heart disease is a nutrition-related disease that is the leading cause of death in the United States. Good nutrition plays a role in reducing the risk of four of the top ten leading causes of death in the United States: heart disease, cancer, stroke, and diabetes.

All of the following are energy-yielding macronutrients EXCEPT:

> minerals Minerals are not macronutrients; that is, they do not provide energy in the form of calories. A macronutrient is a type of nutrient that contains calories that provide energy. Carbohydrates, fats (lipids), and proteins are macronutrients. They are called this because the body requires more of them than it does other nutrients. Minerals, though equally important as macronutrients to good health, are considered micronutrients because they are required in smaller amounts. Minerals do not provide calories, but the body needs them in order to convert the carbohydrates, fats, and proteins to energy and to sustain numerous chemical reactions.

Ian is writing a research paper about the effect of caffeine on blood pressure. Where is the best place for him to look for reliable resources?

> peer-reviewed journal articles The best place to look for reliable resources for a research paper about the role of caffeine on blood pressure is in peer-reviewed journal articles. A peer-reviewed journal is a research journal in which fellow scientists (peers) review studies to assess if they are accurate and sound before they are published. Articles published in a peer-reviewed journal have been thoroughly reviewed by experts in that area of research. Headlines in newspapers, lead articles on websites, articles in popular magazines, and the sound bites on television often report the results of a single, recent research study. While the media publicizes results from studies deemed newsworthy, in reality, it takes many, many affirming research studies before a consensus is reached about nutrition advice. If the research presented in books in the library hasn't been previously published in a peer-reviewed journal, there is no way of knowing if the study was conducted in an appropriate manner and whether the findings are accurate.

What is the definition of nutrition?

> the scientific study of how the nutrients and compounds in the foods people eat nourish and affect their body functions and health Nutrition is the scientific study of how the nutrients and compounds in the foods people eat nourish and affect their body functions and health. Nutrition plays an invaluable role in health. As with any science, nutrition is not stagnant. Researchers will continue to make exciting discoveries about the roles that diet and foods play in keeping people healthy. The study of genes is known as genetics. The study of how the body functions is known as physiology. The study of hormones and how they function in the body is known as endocrinology.

Today, Jill consumes 1,600 total kilocalories. She eats 50 grams of protein. The percentage of Jill's total energy intake that comes from protein is __________.

> 12.5% If Jill eats 1,600 kilocalories and 50 grams of protein today. The percentage of total energy that comes from protein is 12.5%. To perform this calculation, you need to remember that protein provides 4 kcal per gram. Next: a. Multiply the total grams of protein Jill eats (50 grams) by the energy value for protein: 50 g protein X 4 kcal/g = 200 kcal protein consumed b. Divide 200 kcal protein by the total kcal Jill consumes (1,600 kcal), and multiply by 100. This will give you the percentage of Jill's total energy that comes from protein: 200 kcal protein consumed / 1,600 kcal total consumed = 0.125; 0.125 X 100 = 12.5% of total energy comes from protein.