Energy Balance & Body Mass Control Intro (1)

Question 1

What is energy balance?

Answer 1

Energy intake
Energy expenditure

Question 2

What does energy expenditure involve?

Answer 2

Basal activity
Adaptive thermogenesis
Physical activity

Question 3

When does obesity develop?

Answer 3

When energy intake exceeds expenditure

Question 4

Do obese people have higher metabolic rates?

Answer 4

Yes

Question 5

In which groups is obesity prevalence increasing at a higher rate?

Answer 5

Lower socially economic groups
Over 40s
Ethnic minorities

Question 6

What is meant by the term ‘energy dense’ foods?

Answer 6

Foods that are high in fats and sugars but low in water content.
Portion size is not be extremely large, but the energy (fat/sugar content) of the food is extremely large

Question 7

Why is there a permissive effect towards energy drinks?

Answer 7

The body doesn’t detect liquid calories as effectively.
Overconsumption of fatty drinks does not ‘fill you up’ - can lead to overeating - even higher calorie intake

Question 8

Over time, energy intake has decreased by obesity levels have continued to increase. What is the cause of this?

Answer 8

Substantial decrease in energy expenditure:
More sedentary behaviour
Less physical activity

Question 9

What other issues does obesity increase the risk of?

Answer 9

Cancer (~10% increased risk)
Cardiovascular disease
Type 2 diabetes
Gallstones
Arthritis
Sick leave
Psychosocial Problems

Question 10

What is diabetes?

Answer 10

Abnormalities in insulin release and action
Specifically inadequate release and/or insulin resistance

Question 11

How is diabetes diagnosed?

Answer 11

Tolerance test: 75mg oral glucose given, baseline and 2hr blood glucose levels measured

Question 12

What does diabetes lead to?

Answer 12

Too much glucose in the blood
Disturbances of function and metabolism

Question 13

What glucose levels are considered normal, impaired and diabetic?

Answer 13

Fasting/baseline 2 hour

Normal <5.5 <7.8
IGT <7.0 7.8-11.0
Diabetes >7.0 >11.1

(IGT= Impaired Glucose Tolerance)

Question 14

What is insulin release stimulated by?

Answer 14

Glucose and amino acids
Parasympathetic nervous system
Gut hormones (e.g., GIP, CCK)

Question 15

What are the actions of insulin?

Answer 15

Stimulates glucose uptake in skeletal muscle and adipose tissue
Stimulates glycogen storage in liver and muscle
Stimulates lipid synthesis and storage from triglycerides
Inhibits proteolysis and facilitates protein synthesis
Inhibits lipolysis and ketogenesis

Question 16

How is diabetes classified?

Answer 16

Type 1: Insulin dependent
Type 2: Non-insulin dependent

Question 17

What are other causes of diabetes mellitus?

Answer 17

Pancreatic disease (e.g., pancreatitis/pancreatectomy/haemochromatosis)
Endocrine disease (e.g., acromegaly/Cushing’s syndrome)
Drugs and chemicals (e.g., steroids/betablockers/diuretics)
Inherited disease (e.g., MODY/DIDMOAD/Cystic fibrosis)

Question 18

How does insulin resistance relate to progressive beta-cell failure in type 2 diabetes?

Answer 18

Insulin resistance -> Hyperinsulinaemia -> Increased insulin resistance -> beta-cell failure -> hypoinsulinaemia

Impaired glucose tolerance (caused by insulin resistance) -> hyperglycaemia (Type 2 diabetes)
Accelerated by beta-cell failure

(Genetic and environmental effects also contribute)

Question 19

What are some complications of diabetes?

Answer 19

~50% of patients already have at least one complication at time of diagnosis

Ischaemic skin changes to feet: 6%
Intermittent claudication: 3%
Plasma creatinine >120µmol/l: 3%
Stroke or TIA: 1%
Hypertension: 35%
Retinopathy: 21%
Erectile dysfunction: 20%
Abnormal ECG: 18%
Absent foot pulses: 13%
Myocardial infarction: 1%

Question 20

How does diabetes affect life expectancy?

Answer 20

Decreased life expectancy
Adults with diabetes have an annual mortality of about 5.4% (double the rate for non-diabetic adults)
Life expectancy is decreased by 5–10 years

Increased risk of:
Macrovascular disease: increased risk of coronary heart disease and stroke
Peripheral vascular disease: greater non-traumatic amputation risk