Health Sciences 1001A/B Chapter Notes - Chapter 5: Trans Fat, Essential Amino Acid, Dietary Fiber

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Published on 19 Apr 2013
School
Western University
Department
Health Sciences
Course
Health Sciences 1001A/B
Professor
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Chapter Five: Nutrition Basics
Diet and Nutrition:
- An area in which you have high control
- Provides body with nutrients required to produce energy, repair damaged tissue, promote
tissue growth, regulate physiological processes
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
Nutritional Requirements:
- Body requires proteins, fats, carbohydrates, minerals and water (essential nutrients)
- Essential = must get substances from food because body is unable to manufacture them
(or not enough to meet physiological needs)
- Body obtains nutrients through digestion
- Energy in food expressed in kilocalories = scientific expression of energy value in a food
Three classes of essential nutrients supply energy:
1. Fat = 9 calories per gram
2. Protein = 4 calories per gram
3. Carbohydrates = 4 calories per gram
- If all types of calories > energy expenditure = converted to fat and stored in the body
Protein:
- Found in every living cell
- Promotes growth and maintenance of body tissue
- Primary component of muscles and connective tissue
- Form important parts of blood, enzymes, some hormones, and cell membranes
- Composed of chains on amino acids
- When an essential amino acid is missing from diet, it will result in deficiencies
- Foods that contain 9 essential amino acids are complete proteins (milk, meat, fish,
poultry, cheese, eggs, soy beans and tofu)
- Foods that contain less than 9 essential amino acids are known as incomplete proteins
(veggies, grains, legumes, nuts)
- Essential amino acids can be obtained from combinations of incomplete protein sources
(red beans and rice)
Proteins in Weight Management:
- Consumption of protein with carbohydrates delays carbohydrate absorption and
attenuates the body’s insulin response
- Dietary intakes with less than 15% of energy from proteins can result in muscle loss
- Appears to be no difference in lean body mass gains between 15% and 25% protein diets
- High protein diets do not lead to weight loss unless calories are also reduced
Fats (lipids):
- Provide a concentrated form of energy
- Give some foods a pleasing taste, texture
- Help absorption of fat-soluble vitamins (A, D, E, K)
- Insulates our bodies to help retain heat
- Provides a protective cushion for internal organs and bones
- Viable fats represent only roughly 40% of the fat we consume
Dietary fats consist of a combination of 3 forms of fat based on chemical composition:
1. Saturated
- Typically solid at room temperature
- Found naturally in animal products
2. Monosaturated
- Typically liquid at room temperature
- Usually from plant sources (olive and canola oil)
3. Polyunsaturated
- Typically liquid at room temperature
- Usually from plant sources (soybean and corn oil)
- Includes two essential fatty acids
Trans fatty acids = unsaturated fatty acids
- Used to increase stability of oil so it can be reused for deep frying, to increase texture of
foods and to increase shelf life of foods
- Also found in small amounts in meat and mild
- Leading sources of trans fats are deep-fried foods, baked and snack foods, and stick
margarine
** The softer (or more liquid) a fat is, the less saturated and trans fat it is likely to contain
Fats (lipids) and Cholesterol
- Low density lipoprotein (LDL) cholesterol = “bad cholesterol”
- Saturated and trans fatty acids increase blood levels
- High density lipoproteins (HDL) cholesterol = “good cholesterol”
- Monosaturated fatty acids may increase blood levels
- Trans fatty acids may decrease blood levels in large amounts
Fats in Weight Management
- Type of fat (vs. presence of fat) seems to contribute most to CV disease
- Trans fat consistently associated with higher risk coronary heart disease
- Unsaturated fats appear to be most beneficial in terms of cardioprotection
** Choose unsaturated fats instead of saturated and trans fats to decrease risks of heart
disease
Carbohydrates:
- Various combinations of sugar units (saccharides)
- Used primarily for energy
Occur in three forms:
1. Monosaccharides (one unit)
- Glucose (blood sugar)
2. Disaccharides (two units)
- Sucrose (table sugar)
3. Polysccharides (more than two units)
- Starches
Starches are among the most important sources of dietary carbohydrates
- Found primarily in grains, legumes, potatoes and yams
- Unrefined (whole grain) complex carbohydrates are high in fibre, vitamins, minerals, and
other compounds
- Also take longer to chew and digest, enter bloodstream slower

Document Summary

An area in which you have high control. Provides body with nutrients required to produce energy, repair damaged tissue, promote tissue growth, regulate physiological processes. Choosing a healthy diet involves: knowing which nutrients are necessary and in which amounts, translating those requirements into a diet consisting of foods you like and that are available / affordable. Body requires proteins, fats, carbohydrates, minerals and water (essential nutrients) Essential = must get substances from food because body is unable to manufacture them (or not enough to meet physiological needs) Energy in food expressed in kilocalories = scientific expression of energy value in 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 > energy expenditure = converted to fat and stored in the body. Promotes growth and maintenance of body tissue. Primary component of muscles and connective tissue.