Chapter 2: Guidelines for a Healthy Diet
EXCI 204 — Food for Sport · Chapter Study Notes
Chapter Overview
“What you don’t know could kill you” may have been the first nutrition recommendation — swallowing
the wrong berry or drinking from a suspect water source could have been fatal to early humans. As
societies developed, dietary cautions turned into taboos, sometimes laws, and ultimately nutrition
recommendations.
Governments have provided modern nutrition information for the past 150 years. During the Industrial
Revolution in Great Britain, urban populations (and poverty and hunger) swelled, so the British
government developed minimum dietary guidelines using the cheapest foods. Not until World War I
did the British Royal Society determine that a healthy workforce required a healthy diet — not
necessarily the cheapest — so fruits, vegetables, and milk became part of nutritional guidance. Since
then virtually every nation has sought to set dietary standards. Today’s public health information isn’t
always understood or used properly; as portion sizes grow, so do waistlines.
The chapter covers: (2.1) the purpose and history of U.S. nutrition recommendations and how
nutritional status is assessed; (2.2) the Dietary Reference Intakes — five nutrient-intake values and two
energy values; (2.3) the four Dietary Guidelines for Americans, 2020–2025 and their limits; (2.4) MyPlate
and the Choice (Exchange) Lists; and (2.5) food labels (Nutrition Facts, ingredient list, nutrient content
and health claims) and dietary supplement labels.
2.1 Nutrition Recommendations
Learning objectives: Explain the purpose of government nutrition recommendations · Discuss how the
focus of U.S. nutrition recommendations has changed over the past 100 years · Describe the information
needed to assess an individual’s nutritional status.
Personal preferences and our food environment influence food choices, but these may not be healthy:
our taste buds respond to flavor rather than sensible nutrition, and restaurants and food
manufacturers want to sell products, not necessarily promote a healthy diet. Government
recommendations are designed with individual health as well as public health in mind. They can be
used to plan diets and to evaluate what we are eating, both as individuals and as a nation.
Past and Present U.S. Recommendations ⭐
The U.S. federal government has made nutrition recommendations for over 100 years; they have
changed as food intake patterns changed and our knowledge of a healthy diet evolved.
• 1894 — USDA: the first U.S. dietary recommendations suggested amounts of protein,
carbohydrate, fat, and “mineral matter.” Specific vitamins and minerals had not yet been
identified, but this set the stage for the first food guides.
• Early 1940s (WWII) — Food and Nutrition Board established to advise the Army and other federal
agencies on food and the nutritional health of the armed forces and general population. It
developed the first recommendations for specific nutrient amounts — the Recommended Dietary
Allowances (RDAs).
EXCI 204 · Chapter 2 · Page 1
, • The original RDAs covered energy and the nutrients most likely to be deficient: protein, iron,
calcium, vitamins A and D, thiamin, riboflavin, niacin, and vitamin C. Intakes were based on
amounts that would prevent nutrient deficiencies.
KEY DEFINITION ⭐
food guide — (Described in text) A tool designed to help people choose foods that make up a
healthy diet; food guides translate nutrient intake recommendations into food intake
recommendations.
Shift in focus ⭐. Overt nutrient deficiencies are now rare in the U.S., but nutrition-related chronic
diseases (heart disease, diabetes, osteoporosis, obesity) have increased. Recommendations are now
intended to promote health as well as prevent deficiencies:
• The original RDAs were expanded into the Dietary Reference Intakes, which address problems of
excess as well as deficiency.
• The Dietary Guidelines for Americans — diet and lifestyle recommendations that promote health
and reduce risks of obesity and other chronic diseases — introduced in 1980, revised every five
years.
• Early food guides evolved into MyPlate, built around the Dietary Guidelines’ recommendations for
five food groups.
• Standardized food labels help consumers choose foods that meet these recommendations.
Timeline of U.S. Food Guides ⭐
Year Food guide Key features (Figure 2.1)
1917 How to Select Foods Met nutritional needs economically; five groups: meat and
milk, cereals, vegetables and fruit, fats and fatty foods, sugars
and sugary foods
1943 Basic Seven (USDA, WWII) Seven food groups; to help maintain nutritional health under
wartime rationing
1956 Basic Four Simplified from seven to four; focused on getting adequate
nutrients by specifying amounts from each group
1979 Hassle-Free Food Guide Basic Four plus a fifth group highlighting the need to limit
sweets, fats, and alcohol
1984 Food Wheel Divided fruits and vegetables into two groups; added
recommendations for varying calorie needs
1992 Food Guide Pyramid Goals for both adequate nutrients and avoiding excesses;
pyramid shape emphasized the relative contribution of each
group (bread/cereal/rice/pasta 6–11 servings; vegetables 3–5;
fruit 2–4; milk/yogurt/cheese 2–3; meat/poultry/fish/dry
beans/eggs/nuts 2–3; fats, oils, sweets use sparingly)
2005 MyPyramid: Steps to a Changed shapes/arrangement to stress portion size; added a
Healthier You band for oils and the concept of physical activity
EXCI 204 · Chapter 2 · Page 2
, Year Food guide Key features (Figure 2.1)
2011 MyPlate Plate visual showing how much of your plate should be filled
with each food group to meet needs and avoid excess
How food guides present recommendations has changed, but the basic message has stayed the same:
choose the right combinations of foods to promote health.
DEBATE — EXAM EXAMPLE
How Involved Should the Government Be in Your Food Choices?
The issue: poor U.S. dietary habits contribute to a high incidence of nutrition-related chronic disease
(obesity, diabetes, high blood pressure, heart disease). Low fruit and vegetable intake is linked to
increased risk of heart disease and obesity. The direct annual health-care cost of obesity alone is
estimated at over $480 billion, and almost one in four military applicants is rejected for being
overweight — which some suggest threatens national security and military readiness.
• Advocates of government involvement: our food environment causes unhealthy habits.
Obesity expert Dr. Kelly Brownell believes environment plays a more powerful role than
personal irresponsibility. Areas with many fast-food restaurants and sources of foods high in
saturated fat, added sugars, and/or sodium have higher obesity rates. The “noxious” food
environment should be managed like any public health threat — just as regulations keep food
free of harmful bacteria, they could keep restaurant meals from providing excessive nutrients.
Problem: unlike bacteria, individual foods are hard to classify as healthy or unhealthy.
• Punitive measures: taxing junk food (e.g., sugary drink taxes in Chicago, Philadelphia, and
Berkeley, California); zoning to keep fast food away from schools and child-care facilities;
limiting foods advertised on children’s television; restricting portion sizes sold.
• Incentives: making fruits and vegetables less expensive; reimbursing food assistance recipients
for fruit and vegetable purchases; doubling food assistance dollars spent on these foods.
• Opponents: not the government’s responsibility and an infringement on personal freedom;
individuals must take responsibility. The food industry should work with the public — e.g.,
General Mills and Kellogg’s whole-grain cereals; Wal-Mart working with suppliers to reduce
sodium and added sugars in packaged foods.
• Conclusion: unhealthy eating is easy (high-calorie, salty, sugary foods available 24/7 in
excessive portions). A synergy of policy intervention, industry cooperation, and personal
efforts is likely needed. All measures support, but do not excuse, individual responsibility.
How We Use Nutrition Recommendations
Nutrition recommendations are developed to address the nutritional concerns of the population and
help individuals meet their nutrient needs. They are also used to evaluate the nutrient intake of
populations and individuals. Comparing what people eat to recommendations is important for assessing
nutritional status.
KEY DEFINITION ⭐
nutritional status — An individual’s health, as it is influenced by the intake and utilization of
nutrients.
EXCI 204 · Chapter 2 · Page 3
, Populations. Food intake can be assessed by having individuals record or recall intake, or by using
information about the amounts and types of food available to the population to identify dietary trends.
EXAM EXAMPLE — WHAT A SCIENTIST SEES
Trends in Milk Consumption
U.S. milk consumption estimates (based on milk available for human consumption) show total milk
and whole milk declined while lower-fat milks increased. A nutrition scientist sees the health
implications:
• Benefit: whole milk is high in saturated fat, so replacing it with lower-fat milk decreases
saturated fat intake, potentially reducing heart disease risk.
• Concern: milk is the most important source of calcium in the North American diet; calcium is
needed for bone health, so reduced total milk intake could increase fractures from low bone
density (osteoporosis).
Interpret the Data (graph reading): total milk falls from roughly 31 gallons/person/year (1970) to
roughly 18 (2016) — about 13 gallons less × 4.8 g calcium per gallon ≈ 62 g less calcium per person
per year.
Individuals. Food intake is evaluated along with health and medical history to assess nutritional status.
Accurate records are difficult:
• Food records and recalls rely on the consumer’s memory and reliability, so may be inaccurate.
• Food frequency questionnaires ask about intake patterns but also rely on subjective responses, so
are prone to similar errors.
• Combining one or more methods often gives a more accurate picture of typical intake.
KEY DEFINITION
food frequency questionnaire — (Described in text) A questionnaire that asks consumers about
their food intake patterns; relies on subjective responses.
Assessing Nutritional Status — 5 Steps ⭐
Step What it involves (Figure 2.2 — Process Diagram)
1. Determine typical food Recall with the help of a trained interviewer, or record all food and
intake beverages as consumed. A cell phone app is convenient and has been
shown to be more accurate than recalling later. Because intake varies
day to day, track for more than one day.
2. Compare intake to Quick: compare food intake to MyPlate food group recommendations.
recommendations Thorough: compare intake of individual nutrients to
recommendations.
3. Evaluate physical health A physical exam can detect signs of deficiency or excess. Height and
weight can be monitored over time or compared with population
standards; drastic changes or values significantly above/below
standards could indicate deficiency or excess.
EXCI 204 · Chapter 2 · Page 4
EXCI 204 — Food for Sport · Chapter Study Notes
Chapter Overview
“What you don’t know could kill you” may have been the first nutrition recommendation — swallowing
the wrong berry or drinking from a suspect water source could have been fatal to early humans. As
societies developed, dietary cautions turned into taboos, sometimes laws, and ultimately nutrition
recommendations.
Governments have provided modern nutrition information for the past 150 years. During the Industrial
Revolution in Great Britain, urban populations (and poverty and hunger) swelled, so the British
government developed minimum dietary guidelines using the cheapest foods. Not until World War I
did the British Royal Society determine that a healthy workforce required a healthy diet — not
necessarily the cheapest — so fruits, vegetables, and milk became part of nutritional guidance. Since
then virtually every nation has sought to set dietary standards. Today’s public health information isn’t
always understood or used properly; as portion sizes grow, so do waistlines.
The chapter covers: (2.1) the purpose and history of U.S. nutrition recommendations and how
nutritional status is assessed; (2.2) the Dietary Reference Intakes — five nutrient-intake values and two
energy values; (2.3) the four Dietary Guidelines for Americans, 2020–2025 and their limits; (2.4) MyPlate
and the Choice (Exchange) Lists; and (2.5) food labels (Nutrition Facts, ingredient list, nutrient content
and health claims) and dietary supplement labels.
2.1 Nutrition Recommendations
Learning objectives: Explain the purpose of government nutrition recommendations · Discuss how the
focus of U.S. nutrition recommendations has changed over the past 100 years · Describe the information
needed to assess an individual’s nutritional status.
Personal preferences and our food environment influence food choices, but these may not be healthy:
our taste buds respond to flavor rather than sensible nutrition, and restaurants and food
manufacturers want to sell products, not necessarily promote a healthy diet. Government
recommendations are designed with individual health as well as public health in mind. They can be
used to plan diets and to evaluate what we are eating, both as individuals and as a nation.
Past and Present U.S. Recommendations ⭐
The U.S. federal government has made nutrition recommendations for over 100 years; they have
changed as food intake patterns changed and our knowledge of a healthy diet evolved.
• 1894 — USDA: the first U.S. dietary recommendations suggested amounts of protein,
carbohydrate, fat, and “mineral matter.” Specific vitamins and minerals had not yet been
identified, but this set the stage for the first food guides.
• Early 1940s (WWII) — Food and Nutrition Board established to advise the Army and other federal
agencies on food and the nutritional health of the armed forces and general population. It
developed the first recommendations for specific nutrient amounts — the Recommended Dietary
Allowances (RDAs).
EXCI 204 · Chapter 2 · Page 1
, • The original RDAs covered energy and the nutrients most likely to be deficient: protein, iron,
calcium, vitamins A and D, thiamin, riboflavin, niacin, and vitamin C. Intakes were based on
amounts that would prevent nutrient deficiencies.
KEY DEFINITION ⭐
food guide — (Described in text) A tool designed to help people choose foods that make up a
healthy diet; food guides translate nutrient intake recommendations into food intake
recommendations.
Shift in focus ⭐. Overt nutrient deficiencies are now rare in the U.S., but nutrition-related chronic
diseases (heart disease, diabetes, osteoporosis, obesity) have increased. Recommendations are now
intended to promote health as well as prevent deficiencies:
• The original RDAs were expanded into the Dietary Reference Intakes, which address problems of
excess as well as deficiency.
• The Dietary Guidelines for Americans — diet and lifestyle recommendations that promote health
and reduce risks of obesity and other chronic diseases — introduced in 1980, revised every five
years.
• Early food guides evolved into MyPlate, built around the Dietary Guidelines’ recommendations for
five food groups.
• Standardized food labels help consumers choose foods that meet these recommendations.
Timeline of U.S. Food Guides ⭐
Year Food guide Key features (Figure 2.1)
1917 How to Select Foods Met nutritional needs economically; five groups: meat and
milk, cereals, vegetables and fruit, fats and fatty foods, sugars
and sugary foods
1943 Basic Seven (USDA, WWII) Seven food groups; to help maintain nutritional health under
wartime rationing
1956 Basic Four Simplified from seven to four; focused on getting adequate
nutrients by specifying amounts from each group
1979 Hassle-Free Food Guide Basic Four plus a fifth group highlighting the need to limit
sweets, fats, and alcohol
1984 Food Wheel Divided fruits and vegetables into two groups; added
recommendations for varying calorie needs
1992 Food Guide Pyramid Goals for both adequate nutrients and avoiding excesses;
pyramid shape emphasized the relative contribution of each
group (bread/cereal/rice/pasta 6–11 servings; vegetables 3–5;
fruit 2–4; milk/yogurt/cheese 2–3; meat/poultry/fish/dry
beans/eggs/nuts 2–3; fats, oils, sweets use sparingly)
2005 MyPyramid: Steps to a Changed shapes/arrangement to stress portion size; added a
Healthier You band for oils and the concept of physical activity
EXCI 204 · Chapter 2 · Page 2
, Year Food guide Key features (Figure 2.1)
2011 MyPlate Plate visual showing how much of your plate should be filled
with each food group to meet needs and avoid excess
How food guides present recommendations has changed, but the basic message has stayed the same:
choose the right combinations of foods to promote health.
DEBATE — EXAM EXAMPLE
How Involved Should the Government Be in Your Food Choices?
The issue: poor U.S. dietary habits contribute to a high incidence of nutrition-related chronic disease
(obesity, diabetes, high blood pressure, heart disease). Low fruit and vegetable intake is linked to
increased risk of heart disease and obesity. The direct annual health-care cost of obesity alone is
estimated at over $480 billion, and almost one in four military applicants is rejected for being
overweight — which some suggest threatens national security and military readiness.
• Advocates of government involvement: our food environment causes unhealthy habits.
Obesity expert Dr. Kelly Brownell believes environment plays a more powerful role than
personal irresponsibility. Areas with many fast-food restaurants and sources of foods high in
saturated fat, added sugars, and/or sodium have higher obesity rates. The “noxious” food
environment should be managed like any public health threat — just as regulations keep food
free of harmful bacteria, they could keep restaurant meals from providing excessive nutrients.
Problem: unlike bacteria, individual foods are hard to classify as healthy or unhealthy.
• Punitive measures: taxing junk food (e.g., sugary drink taxes in Chicago, Philadelphia, and
Berkeley, California); zoning to keep fast food away from schools and child-care facilities;
limiting foods advertised on children’s television; restricting portion sizes sold.
• Incentives: making fruits and vegetables less expensive; reimbursing food assistance recipients
for fruit and vegetable purchases; doubling food assistance dollars spent on these foods.
• Opponents: not the government’s responsibility and an infringement on personal freedom;
individuals must take responsibility. The food industry should work with the public — e.g.,
General Mills and Kellogg’s whole-grain cereals; Wal-Mart working with suppliers to reduce
sodium and added sugars in packaged foods.
• Conclusion: unhealthy eating is easy (high-calorie, salty, sugary foods available 24/7 in
excessive portions). A synergy of policy intervention, industry cooperation, and personal
efforts is likely needed. All measures support, but do not excuse, individual responsibility.
How We Use Nutrition Recommendations
Nutrition recommendations are developed to address the nutritional concerns of the population and
help individuals meet their nutrient needs. They are also used to evaluate the nutrient intake of
populations and individuals. Comparing what people eat to recommendations is important for assessing
nutritional status.
KEY DEFINITION ⭐
nutritional status — An individual’s health, as it is influenced by the intake and utilization of
nutrients.
EXCI 204 · Chapter 2 · Page 3
, Populations. Food intake can be assessed by having individuals record or recall intake, or by using
information about the amounts and types of food available to the population to identify dietary trends.
EXAM EXAMPLE — WHAT A SCIENTIST SEES
Trends in Milk Consumption
U.S. milk consumption estimates (based on milk available for human consumption) show total milk
and whole milk declined while lower-fat milks increased. A nutrition scientist sees the health
implications:
• Benefit: whole milk is high in saturated fat, so replacing it with lower-fat milk decreases
saturated fat intake, potentially reducing heart disease risk.
• Concern: milk is the most important source of calcium in the North American diet; calcium is
needed for bone health, so reduced total milk intake could increase fractures from low bone
density (osteoporosis).
Interpret the Data (graph reading): total milk falls from roughly 31 gallons/person/year (1970) to
roughly 18 (2016) — about 13 gallons less × 4.8 g calcium per gallon ≈ 62 g less calcium per person
per year.
Individuals. Food intake is evaluated along with health and medical history to assess nutritional status.
Accurate records are difficult:
• Food records and recalls rely on the consumer’s memory and reliability, so may be inaccurate.
• Food frequency questionnaires ask about intake patterns but also rely on subjective responses, so
are prone to similar errors.
• Combining one or more methods often gives a more accurate picture of typical intake.
KEY DEFINITION
food frequency questionnaire — (Described in text) A questionnaire that asks consumers about
their food intake patterns; relies on subjective responses.
Assessing Nutritional Status — 5 Steps ⭐
Step What it involves (Figure 2.2 — Process Diagram)
1. Determine typical food Recall with the help of a trained interviewer, or record all food and
intake beverages as consumed. A cell phone app is convenient and has been
shown to be more accurate than recalling later. Because intake varies
day to day, track for more than one day.
2. Compare intake to Quick: compare food intake to MyPlate food group recommendations.
recommendations Thorough: compare intake of individual nutrients to
recommendations.
3. Evaluate physical health A physical exam can detect signs of deficiency or excess. Height and
weight can be monitored over time or compared with population
standards; drastic changes or values significantly above/below
standards could indicate deficiency or excess.
EXCI 204 · Chapter 2 · Page 4
