Nutrition and Diet Therapy
Module 1
Basic Food Concepts in Nutrition and Diet Therapy
Food
Nourishes the body.
Defined as anything eaten or drunk that meets the body's needs for
energy, growth, regulation, and protection.
In short, food is the raw material from which our bodies are made.
Nutrition
The science of food, including the nutrients and other substances it
contains.
It involves the study of:
o Ingestion
o Digestion
o Absorption
o Transport
o Metabolism
o Interaction
o Storage
o Excretion of food substances.
Nutrition also includes the study of the environment and human
behavior as they relate to these processes.
Nutrients
Nutrients are components of food that the body needs in adequate amounts to:
Grow
Reproduce
Maintain a normal, healthy life
The six essential nutrients are:
Water
Proteins
Fats
Carbohydrates
Minerals
Vitamins
Food Choices
Food choices are an integral part of a person’s lifestyle, and many
people find it difficult to change their eating habits.
Health care professionals must understand the dynamics of food
choices when helping clients change their diets.
People are more likely to make lasting dietary changes when their food
preferences are respected.
Cultural Competence in Nutrition
Cultural competence is essential for health professionals to respect
individual
preferences and help clients achieve a nutritious, acceptable diet.
This includes being aware of and sensitive to cultural food traditions and
beliefs.
Impact of Food Choices on Health
Food choices can influence health both positively and negatively.
A single food choice doesn’t make or break a healthy diet.
However, the overall balance of foods chosen over time can make a
significant difference to a person’s health.
Factors that influence personal food choices:
⎯ Preference
⎯ Habits
⎯ Associations
⎯ Ethnic Heritage and Regional Cuisines
⎯ Values
⎯ Social Interaction
⎯ Availability, Convenience, and Economy
⎯ Age, Body Weight and Image
⎯ Medical Conditions, Health and Nutrition
The Nutrients
There are six classes of nutrients: water, carbohydrates, fats, proteins, vitamins,
and minerals.
In addition, foods contain other substances like pigments and phytochemicals
which are not nutrients, but may still contribute to good health.
The body can produce some nutrients in small amounts, but not enough to meet
its needs. Therefore, it must get many nutrients from food. These are called
essential nutrients.
Organic Nutrients
(Carbohydrates, Fats, Proteins, and Vitamins)
Carbohydrates, fats, and proteins provide energy during metabolism
(except vitamins, which do not).
These are known as energy-yielding nutrients because they replenish
the energy the body uses daily.
Vitamins help release energy from these nutrients.
The energy they release is measured in kilocalories (kcal) — small units
of energy (e.g., one apple provides tens of thousands of calories).
Inorganic Nutrients
(Minerals and Water)
Minerals do not provide energy, but they help regulate energy release
and perform many other body functions.
Water is essential as it serves as the medium for all bodily processes.
Dietary Reference Intakes (DRI)
A set of standards that define recommended amounts of energy, nutrients,
other dietary components, and physical activity to promote optimal health.
4 Categories of DRI:
1. Recommended Dietary Allowance (RDA)
o Average daily nutrient intake sufficient to meet the needs of
nearly all (97–98%) healthy individuals.
o Used as a goal for individual intake.
2. Adequate Intake (AI)
o Set when there isn’t enough evidence to establish an RDA.
o Used as a guide for nutrient intake when scientific data is
limited.
3. Estimated Average Requirement (EAR)
o Nutrient intake value estimated to meet the needs of 50% of
healthy individuals in a specific group.
o Used in research and policymaking, and to help determine the
RDA.
4. Tolerable Upper Intake Level (UL)
o Maximum daily intake unlikely to cause harm in most healthy
people.
o Helps prevent toxicity from excessive nutrient intake.
Key Purposes:
EAR: For group nutrition planning (e.g., schools, military).
RDA or AI: For individual nutrient goals.
UL: To help avoid nutrient overconsumption and health risks.
Estimated Energy Requirement (EER)
The EER is the amount of daily energy (calories) needed to maintain energy
balance in a healthy adult, based on their age, gender, weight, height, and
physical activity level.
Enough energy is essential to support a healthy, active life.
Too much energy can lead to obesity.
Unlike nutrients, energy needs have a clear indicator: body weight.
o Weight loss suggests inadequate energy intake.
o Weight gain indicates excessive energy intake.
Because excess energy leads to weight gain, the DRI committee did not
set a Tolerable Upper Intake Level (UL) for energy.
Acceptable Macronutrient Distribution Ranges (AMDR)
The DRI committee considers both nutrient adequacy and the prevention of
chronic diseases when making dietary recommendations.
To support this, they established the Acceptable Macronutrient Distribution
Ranges (AMDR)—which are healthy intake ranges for the three energy-yielding
nutrients:
Carbohydrates
Fats
Proteins
These nutrients all contribute to a person’s total calorie intake, and their
proportions should vary in a balanced way to promote health and prevent
disease.
The DRI committee recommends the following proportions of daily calorie
intake from energy-yielding nutrients to ensure adequate nutrition and reduce
the risk of chronic diseases:
Carbohydrates: 45–65% of total calories
Fats: 20–35% of total calories
Proteins: 10–35% of total calories
Dietary Guidelines and Food Guides
Overnutrition:
Excess intake of food energy or nutrients that may lead to disease or
increased risk of disease.
Undernutrition:
Inadequate intake of food energy or nutrients that can cause disease or
increased susceptibility to illness.
Dietary Ideals: 6 Characteristics of a Nutritious Diet
1. Adequacy
o Provides all essential nutrients, energy, and fiber needed to
maintain health and body weight.
2. Balance
o Includes foods in the right proportions to meet the body’s needs.
3. kCalorie (Energy) Control
o Maintains healthy body weight by consuming just the right
amount of energy.
o Focus on high nutrient, low-calorie foods.
4. Nutrient Density
o The amount of nutrients a food provides relative to its calorie
content.
o Higher nutrient density = healthier choice.
5. Moderation
o Eating enough, but not too much of any food or nutrient.
6. Variety
o Choosing different foods from all food groups to ensure a broad
intake of nutrients.
To maintain a healthy and balanced diet, individuals should eat foods from all
food groups daily. For a person requiring 2000 kilocalories per day
Activity Level Definitions
Sedentary
A lifestyle that includes only routine daily activities, such as eating,
cooking, or office work, with little or no physical exercise.
Active
A lifestyle that includes regular physical activity, such as walking more
than 3 miles per day at a pace of 3 to 4 miles per hour, in addition to
daily routine tasks.
Food Labels Overview
Food labels help consumers make informed choices. Key components include the
Ingredient List, Nutrition Facts Panel, Daily Values, and Label Claims.
1. Ingredient List
Found on all packaged foods.
Lists ingredients in descending order by weight (heaviest first).
Helps identify the main components of the food.
2. Nutrition Facts Panel
Required by the FDA.
Shows:
o Serving size
o Calories per serving
o Nutrient quantities
o % Daily Values (%DV)
Recent updates aim to reflect current nutrition science for easier
interpretation.
3. Daily Values (DV)
Based on a 2000 kcal/day diet.
The %DV column shows how much a nutrient in one serving contributes
to daily intake goals.
Actual needs may vary depending on individual energy requirements.
4. Claims on Food Labels
Type of Claim Definition
Describe the amount of a nutrient (e.g., “low fat,” “high
Nutrient Claims
in fiber”).
Link a nutrient/substance to a health condition (e.g.,
Health Claims
calcium and osteoporosis).
Structure-Function Describe how a substance affects the body (e.g., “calcium
Claims builds strong bones”)
