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Chapter 5 : Nutrition Basics 2/26/2012 1:45:00 PM
Diet and Nutrition
- An area in which you have increased control
- Provides body with nutrients requiredto produce energy, repair
damaged tissue, promote tissue growth, regulate physiological
Choosing a healthy diet involves:
1) Knowing which nutrients are necessary and in which amounts
2) Translating those requirements into a diet consisting of foods
you like and that are available/affordable.
-Body requires proteins, fats, carbohydrates, vitamins, minerals and
water = ESSENTIAL NUTRIENT
-Essential = must get substances from because body is
unable to manufacture them (or not enough to meet physiological
- Body obtains nutrients through digestion.
- Energy in food expressed in kilocalories = scientific expression of
the energy values of a food.
Three classes of essential nutrients supply Energy:
Fat= 9 calories per gram
Protein = 4 calories per gram
Carbohydrates = 4 calories per gram
**If all types of calories > energyneeds = converted to fat and
stored in the body
- Found in every living cell
- Promotes growth and maintenance of body tissue
- Primary component of muscle and connective tissues.
- Form important parts of blood, enzymes, some hormones, and cell
- Composed of chains of amino acids
- When an essential amino acids is missing from diet " deficiency
- Foods that contain 9 essential amino acids are complete proteins
(milk, meat, fish, poultry, cheese, eggs, soy beans, tofu)
- Foods that contain essential amino acids are incomplete
proteins (vegetables, grains, legumes, nuts)
- Essential amino acids can beobtained from combinations of
incomplete protein sources (e.g., red beans and rice) – 20% of daily
- Provide a concentrated form of energy.
- Give some foods a pleasing taste, texture
- Help absorption of fat-soluble vitamins store in our fat – toxic
amount if taken in high doses.
- Insulates our bodies to help retain heat.
- Provides a protective cushion for internal organs and bones
- Visible fats represent only 40% of the fat we consume hidden fats.
Dietary fat consists of a combination of 3 forms of fat based on
chemical composition :
- typically _____________ at room temperature
- found naturally in animal products (Eg: meat and cheese)
2) Monounsaturated fats
- typically liquid at room temperature
- usually from plant sources (e.g., olive and canola oil)
- typically liquid at room temperature" usually from plant
sources (e.g., soybean and corn oil) " includes 2 essential fatty
- linoleic acid an alpha linoleic acid – omega 3 and omega 6.
- soybean and corn oil limit omega 6 but increase omega 3.
- Food fats usually composed of saturated and trans fatty acids.
- Dominant type of fatty acid determines the fat’s characteristics
(e.g., solid vs. liquid)
EXCEPTION #1: Hydrogenation – used as a preservative method
- a process by which hydrogens are added to unsaturated fats.
- turns liquid oils into solid fats
- produces a mixture of saturated fatty acids and standard
and trans forms of unsaturated fatty acids.
Trans fatty acids -- unsaturated fatty acids
- Used to increase stability of oil so it can be reused for deep frying,
to ↑ texture of foods, and to increase shelf life of foods
- Also found in small amounts in meat and milk (naturally)
- Leading sources are ______________________
________________________________________ **the softer (or
more liquid) a fat is, the less saturated and trans fat it is likely to
EXCEPTION #2: Tropical oils
- E.g., coconut, palm, palm kernel
- Contain higher percentages of saturated fats (e.g., coconut
oil = 92% saturated fat)
- Can be found in some brands of snack foods, breakfast
Fats and cholesterol
- Low density lipoproteins (LDL) cholesterol – “bad cholesterol”
- Saturated and trans fatty acids ↑ blood levels ! Unsaturated fatty
acids ↓ blood levels
High-density lipoproteins (HDL) cholesterol – “good cholesterol”
- Monounsaturated fatty acids may ↑ blood levels ! Trans fatty acids
may decrease blood levels in large amounts
**Choose unsaturated fats instead of saturated and trans fats to ↓
risk of heart disease.