Energy Balance & Body Mass Control Intro (1) Flashcards
What is energy balance?
Energy intake
Energy expenditure
What does energy expenditure involve?
Basal activity
Adaptive thermogenesis
Physical activity
When does obesity develop?
When energy intake exceeds expenditure
Do obese people have higher metabolic rates?
Yes
In which groups is obesity prevalence increasing at a higher rate?
Lower socially economic groups
Over 40s
Ethnic minorities
What is meant by the term ‘energy dense’ foods?
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
Why is there a permissive effect towards energy drinks?
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
Over time, energy intake has decreased by obesity levels have continued to increase. What is the cause of this?
Substantial decrease in energy expenditure:
More sedentary behaviour
Less physical activity
What other issues does obesity increase the risk of?
Cancer (~10% increased risk)
Cardiovascular disease
Type 2 diabetes
Gallstones
Arthritis
Sick leave
Psychosocial Problems
What is diabetes?
Abnormalities in insulin release and action
Specifically inadequate release and/or insulin resistance
How is diabetes diagnosed?
Tolerance test: 75mg oral glucose given, baseline and 2hr blood glucose levels measured
What does diabetes lead to?
Too much glucose in the blood
Disturbances of function and metabolism
What glucose levels are considered normal, impaired and diabetic?
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)
What is insulin release stimulated by?
Glucose and amino acids
Parasympathetic nervous system
Gut hormones (e.g., GIP, CCK)
What are the actions of insulin?
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
How is diabetes classified?
Type 1: Insulin dependent
Type 2: Non-insulin dependent
What are other causes of diabetes mellitus?
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)
How does insulin resistance relate to progressive beta-cell failure in type 2 diabetes?
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)
What are some complications of diabetes?
~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%
How does diabetes affect life expectancy?
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
