Lecture 4 - Energy and Carbohydrates Flashcards
What 4 macronutrients is dietary energy derived from and what are their energy values?
- Carbohydrates; 16.7kJ
- Fat; 37.7kJ
- Protein; 16.7kJ
- Alcohol; 29.3kJ
What 4 things result in energy expenditure?
- Diet induced thermogenesis (digest, absorb, transport, store food = 10%)
- Basal metabolism (life processes = 70%)
- Exercise
4 . Growth, pregnancy & lactation
What are some dietary sources of carbohydrates?
- Cereals
- Root crops
- Sugar cane and beet
- Pulses/legumes
- Vegetables
- Fruit
- Milk products
What are 4 common classifications for carbohydrates
- Monosaccharide (Glucose, fructose, galactose)
- Disaccharides (Sucrose, lactose, maltose)
- Oligosaccharides (3-11 mono; Fructo-oligosaccharide and inulin)
- Polysaccharides (12+ mono; Starch, cellulose)
Explain the difference between total sugar, free sugars and added sugars
Total sugar = Includes all sugars from whatever source in a food, and is defined as all monosaccharides and disaccharides other than polyols (sugar alcohols)
Free sugars = Monosaccharides and disaccharides added to foods by the manufacturer, cook and consumer, plus sugars naturally present in honey, syrups and fruit juices
Added sugars = as above but excludes natural sugars
Explain the term complex carbohydrates
- Originally coined to promote consumption of ‘healthy foods’
like wholegrain cereals, fruits and vegetables - Usage changed over the years, now has little useful meaning
- Newer terms; refined and whole grain
Explain the difference between refined and whole grain wheat
Processing wheat separates endosperm, bran and wheat germ from the wheat grain:
- Bran = Protective outer shell; high in fiber and B vitamins
- Endosperm = Contains starch, protein and some vitamins and minerals
- Germ = The seed for a new plant; contains B vitamins, some protein, minerals and healthy oils
What were the findings on wholegrain
- Prospective studies showed a reduction in all-cause mortality, coronary heart disease, cancer deaths, incidence type 2 diabetes, stroke mortality with higher intakes and wholegrains.
- Dose-response relationships (the more whole-grains the better)
- RCTs showed a reduction in bodyweight and cholesterol with more wholegrains
Explain what dietary fiber and its function is
- Derived from plant polysaccharides (multiple sugars) that are resistant to hydrolysis (break down) by human digestive enzymes
- Moves through digestive system absorbing water; reduces risk of constipation
What were the findings on fiber
- Prospective studies showed a reduction in all-cause mortality, cardiovascular disease deaths, cancer deaths, mortality and incidence of type 2 diabetes, stroke incidence with more fibre.
- Dose-response relationships (the more fibre the better)
- RCTs showed a reduction in bodyweight and cholesterol and blood pressure with more fibre
