positive energy balance and disease

Question 1

how many kcal is 1g of fat?

Answer 1

9 kcal

Question 2

does exercise promote weight loss in obese individuals?

Answer 2

on the whole, no

Question 3

reasons why exercise doesn’t promote weight loss in obese people?

Answer 3

high-intensity tasks not feasible for those with high BMI and body fat %

gentle physical actvity will expend 500 kcal but will overreat after so wipe out negative caloric deficit

Question 4

how may the positive effects of exercise be maximised for obese people?

Answer 4

increase in energy expenditure through exercise must be used in conjunction with reduced daily calorie intake

so don’t reverse effects through overreating

Question 5

what is the main principle of dietary advice given to obese people?

Answer 5

remain in negative energy balance

using more than taking in

Question 6

how many calories under someone’s energy requirements is suitable for a diet?

Answer 6

600-700kcal

Question 7

how to determine how much is 600-700 kcal under what someone normally eats?

Answer 7

indirect calorimetry or henry oxford equation -measure basal metabolic rate

calculate energy expenditure

works out energy requirements

Question 8

what are the components of weight loss?

Answer 8

75-90% adipose tissue

10-25% fat free mass (decreases metabolic rate so have to readjust calculations)

Question 9

most typical diet?

Answer 9

low energy content diet e.g mediteranean diet

low fat and more mono than saturated

high fibre (low caloric value as don’t digest)

high protein - requires energy to digest

low glycemic foods to reduce insulin levels promoting storage of energy

Question 10

describe drug treatment for obesity?

Answer 10

orlistat (lipase inhibitor)

• inhibits fat digestion and absorption so calories not stored in body
• side effects of fatty faeces which may stop one eating fat
• 5% weight loss at 3 months
• maintenance rarely achieved

Question 11

describe bariatric surgery as a treatment for obesity?

Answer 11

restrict amount of energy taken into and aborbed into body

e.g gastric bypass surgery which reduces size of stomach so feel full quickly and moves parts of intestine

reduces energy intake by over 1000kcal a day leading to 30% weight loss in first year

stimulates increased release of ‘full’ hormones so stop feeling hungry

problems with protein malnutrition

Question 12

describe type 2 diabetes as an energy overnutrition disease?

cause?
damage as a result?

Answer 12

1 in 10

high blood glucose levels (hyperglycaemia) due to insulin resistance so muscles don’t take up glucose properly or instruct liver to stop producing glucose

damages small blood vessels leading to microvascular diseases and large blood vessels leading to macrovascular disease and nerves

caused by positive energy balance NOT obesity

Question 13

why is type 2 diabetes known as non-insulin dependent?

Answer 13

non-insulin dependent as don’t require more until a few years later when release declines due to excessive release for many years

Question 14

why don’t all obese people have type 2 diabetes?

Answer 14

morbidly obese store fats within adipose tissue (good)

for others, may store fat in abdominal cavity and liver, whether obese or not

depends on distribution of body fat in wrong places not necessarily how much body fat

Question 15

why may fat be stored in the liver?

Answer 15

excess chylomicrons from adipose tissue go to liver
released as VLDL

process impaired and more cholsterol synthesis so more LDL

Question 16

what is the lipid overspill hypothesis?

Answer 16

increase in fat storage or adipose tissue dysfunction then ‘spills over’ to other tissues (incl liver)

begins to interfere with insulin action and tissue becomes more resistant

insulin can’t suppress glycogenolysis and gluconeogenesis in liver which increases blood glucose

also can’t stimulate glucose uptake in muscles

Question 17

what does glycaemic index of a food relate to?

how to work it out?

Answer 17

relates on its effect on blood glucose

divide area under glucose x time curve for e.g starch and divide by area under curve for glucose then x100

Question 18

what indicates whether food has low or high glycaemic index?

Answer 18

high >70

low <55

Question 19

what is the blood glucose response to ingestion of glucose in a regular and type 2 diabetes individual?

Answer 19

regular - levels peak after 30 mins of ingesting and slowly decreases

diabetes - peak is higher and slowly decreases but higher than levels for regular people

Question 20

what is the diagnosis for fasting blood glucose in type 2 diabetes?

and for 2 hours after ingestion of 75g of glucose?

Answer 20

fasting - >7mmol/l

ingestion - >11mmol/l

Question 21

what are the nutritional strategies for type 2 diabetes?

Answer 21

reduce energy intake to improve glycaemia, dislipidaemia and blood pressure

knowledge of carbs which are low and high glycaemic index

Question 22

what has been found about ‘reversing diabetes’?

Answer 22

eating only 600kcals a day

Question 23

how can exercise lower muscle glucose levels?

Answer 23

muscle contraction stimulates GLUT4 translocation to plasma membrane aiding uptake of glucose into muscles

pathways independent of insulin stimulated glucose uptake so not impaired in diabetes

so exercise lowers blood glucose levels as well as liver and muscle triaglycerol