Food Choices: Nutrients and
Nourishment
BIOL 103
Chapter 1
What is Nutrition?
• The science of foods (e.g. nutrients and other
substances), including the relationships to
health and disease; processes within the body
(ingestion, digestion, absorption, transport,
storage, functions, and disposal of end
products); and the social, economic, cultural
and their components, and psychological
implications of eating.
Factors that Influence Food Choices
1.
2.
3.
4.
5.
Sensory
Cognitive
Genetics
Environmental
Health status
Why do we eat the way we do?
• Sensory
1. Flavor/Taste
2. Texture
1. Appearance
Why do we eat the way we do?
• Cognitive
1. Learned food habits/food
reward
2. Social factors
3. Comfort/discomfort foods
4. Advertising
5. Nutrition and health
beliefs
Why do we eat the way we do?
• Environment
1. Economics
1. Lifestyle
2. Availability
3. Cultural Influences
4. Religion
The American Diet
• “Meats and potatoes”
• Americans age 2 and older
consume, on average,
2157 calories (based on
2000 calories diet)
• How healthful is the
“American” diet?
– Too little: fruits, dairy,
vegetables, whole grain
foods
– Too much: saturated fat,
sodium, sugar
Nutrients
• Definition: Any substance that provides
nourishment _______________________ and
the _____________________.
• Essential vs. Non-essential nutrient
– Essential nutrient:
– Non-essential:
• How to determine if it is an nutrient?
– Omit nutrient  decline of health function
– Put nutrient back it (before it’s too late)  regain
health function
The six classes of nutrients
1. Carbohydrates
2. Proteins
3. Lipids (fat)
4. Vitamins
5. Minerals
6. Water
• Macronutrients vs. Micronutrients
General Functions of Nutrients (what
do they do in our body)
1. Provide energy
2. Regulate body processes (ingestion,
digestion, absorption, transport, storage,
functions, and disposal of end products)
3. Build and repair body structures
How nutrients can be categorized…
• Organic or Inorganic?
• What does it mean in science if food is organic?
• _______________________________________
• What is their function?
Carbohydrates
• Carbohydrates: “hydrate
of carbon”
– Made of: sugar molecules
• Function:
– Energy source for cell and
tissues
• Dietary sources: starches
and sugars found in
grains, vegetables,
legumes (dry beans and
peas), fruits, dairy
products
Lipids
• Made of: fatty acids/glycerol
• Functions:
1. Energy storage as
triglycerides
2. Carries fat-soluble vitamins
3. Provides structure for body
cells
• Dietary sources: fats, oils, meat,
dairy, some plants (avocado,
coconut)
Proteins
• Made of: amino acids
• Functions:
1. Energy source
2. Structure for
cells/tissues/body
structures
3. Regulation of body
processes
• Food sources: meats,
dairy products, grains,
legumes, vegetables.
Vitamins
•
Made of: carbon, hydrogen, and
any one or combo of the following
(N, O, P, S, or other elements)
• Function:
1. helps regulate body
processes
2. help extract energy
from carbs, fat, and
proteins
• Dietary sources: meats,
vegetables, grains, dairy,
fats
• Fat Soluble Vitamins
– _________________
– Stored in larger
quantities
• Water Soluble Vitamins
– _________________
– _________________
Minerals
• Inorganic substances
• Macrominerals vs. Microminerals
– Macrominerals:
• Examples: Na, Cl, K, Ca, P, Mg
– Microminerals or “trace minerals”:
• Examples: Fe, Zn, Cu, Mn, Mo, Se, I, Fl
• Functions:
– Structure
– Regulation
• Food sources: all food groups
Water
• Most important
nutrient 
• Functions:
1. Temperature control
2. Lubrication of joints
3. Transportation of
nutrients/wastes
• Dietary sources:
beverages, foods like
fruits and vegetables.
Energy in Food
• We eat nutrients so that we can gain energy
– Energy: capacity to do work
– Q: Which nutrients contain sources of potential
energy?
• Kcal vs. Calories?
• How do we measure energy in Nutrition?
– Kilocalories (kcal)
• 1000 calories = 1 kilocalorie
• 1 kcal: the amount of energy needed to raise the
temperature of 1 kilogram (kg) of water by 1 degree Celsius.
Energy in Food
Use calorie as a general term for energy and kilocalorie as a specific
measurement or unit of that energy.
Problem Set #1
• A) Jeff is eating a snack with 20g of
carbohydrates, 5 grams of proteins, and 3
grams of fat. What is the total amount of
available energy (in kcal) in his snack? (Note:
you will need to show your work for full credit
in an exam).
Problem Set #1
B) Determine the percentages of kilocalories of
carbohydrate, protein, and fat in Jeff’s snack.
Many of the leading causes of death can be avoided by
good diet and exercise
More than 2/3 of U.S. Adults are
overweight/obese
Diet and Health
• Healthy: “a state of complete physical,
mental, and social well-being AND not
merely the absence of disease or
infirmity.” (WHO)
• Disease
– Acute: short-term illness/disease
– Examples:
– Chronic: disease that develop over time
– Examples:
Diet and Health
– Factors that influence Obesity:
1. Behavior
• Calorie imbalance
• Sedentary lifestyle
2. Environment
3. Genetics
Diet and Health
• Physical Activity
– Role in long-term weight
management
• At least ___ mins/day of
moderate activity
– Weight-management
• At least ___ mins/day of
moderate activity
– What is moderate
activity?
Common Study Designs used in
Nutrition Research
1.
Cell culture studies: effect of nutrients on cells
1.
Animal Studies: effect of nutrients on animals
1.
Epidemiological studies: study of disease/death rates in
population groups
– Correlation is not always causation
2.
Case Control Studies: disease vs. those without disease
1.
Clinical/Intervention Trials: experimental vs. control group
– Placebo-controlled
Evaluating Information on the Internet
•
•
•
•
There are no rules for posting on the internet
Consider the source
Keep in mind the scientific method
Be on the lookout for “junk science”
– May distort facts through omission of details