Lec 1 - Intro Flashcards
What are the 4 macronutrients and there kcal per g (energy value/density)
and what is a 65kg persons glycogen, fat and protein?
Carbohydrates (4 kcal/g)
starches, sugars and glycogen (in liver), eg pasta, bread
Fats (9 kcal/g)
triglycerides and others (including cholesterol), eg Dairy fats and oils and nuts
Proteins (4 kcal/g) is a polypeptide
consisting of amino acids (peptides) eg Fish, meat
65 kg person is about
0.5 kg glycogen, 15 kg fat and 12.5 kg protein
difference between glucose and sucrose
Glucose is our simple sugar, mainly stored in the liver, sucrose is a common table sugar, comprised of glucose and fructose
What are polysaccharides?
What are non-starch polysaccharides?
what are monosaccharides?
what is a disaccharide?
Strings of glucose units, three important polysaccharides arestarch, glycogen, and cellulose, all are composed of glucose.
non-starch are fibre
glucose! simple sugar.
Sucrose, comprised of glucose and fructose
what are the energy values for ethanol, fiber and water?
Ethanol (7 kcal/g)
Fibre (< 2 kcal/g) Also known as non-starch polysaccharides
Water (0 kcal/g)
In UK diet, what percentage of energy intake comes from carbs, fat and protein?
45% -carb 40%- fat and 15% protein,
What is energy balance? Do we always have energy balance?
Body expenditure matches Intake
The energy balance will vary during different days, but over time this will level out to a good energy balance
what are the components involved in energy expenditure?
Physical activity Thermogenesis, Diet-Induced Thermogenesis and Resting Metabolic Rate – in healthy person, most is expended through resting-metabolic rate - keeping body ticking over and themo regulation (keeping warm, measured by someone lying still and doing nothing) then physical activity, then diet only uses a small amount
what is 1 kcal in kj
and what are 1000 kcal in Mj?
1 kcal = 4.184 kj
1000 kcal = 4.184 Mj)
Total energy stored in the body is about …… x daily energy intake
they must consume … calories
resting metaolic rate is …
what proportion of this is fat, protein and carb? (and glycogen and free glucose)
60
2300 kcal
1550 kcal resting metabolic rate
Fat stores, 55 x daily energy intake
Protein stores, 20 x daily energy intake*
Carbohydrate stores, <1 x daily energy intake
glycogen 18 h, free glucose 30 min
what percentage of protein can be utilized without serious consequences?
Cannot utilise more than 20% body protein without
serious adverse consequences
What is the stimulus for ‘hunger’ as described by bath analogy?
Not short-term ‘depletion’ of energy stores -
60 days is 180 meals, so missing a meal makes a small small impact on body stores(Like taking a half a saucepan of water from a bath)
More likely it is the absence of fullness
A single meal is like half filling a saucepan with water
When that meal is mostly digested and absorbed, we are ready to eat again
We eat because eating is rewarding and is more rewarding when we like the food and our gut is empty.
obesity is the result of ..
positive energy balance - higher intake relative to expenditure.
what do Prentice and Jebb (1995) suggest causes obestiy? and what period was this measured?
In Britain 1950-1990, paper suggests that it isn’t due to higher intake of energy or fat (these remain constant over time) but due to lower expenditure and inactivity – as measured by increase in both cars per household and television viewing
Kant and Graubard (2006) report trend in..
increase in energy density foods over time.
therefore with an increase in high density foods, and not feeling full, people may eat more and this may explain obesity.
Ledikwe et al. (2006) obese people eat more..
cross sectional study showing obese people eat more energy dense foods
