Obesity - Aetiology Flashcards
Energy balance
Key factor
Intake = expenditure
Maintaining not easy
Set-point theory
Energy intake
Energy consumed that body can metabolise CHO = 3.75kcal/g Protein = 4kcal/g Alcohol = 7kcal/g Fat = 9kcal/g
Total energy expenditure
Basal metabolic rate
Physical activity
Thermal effect of food
Appetite regulation
Peripheral + central signals
Ghrelin - hormone, stomach, stimulates appetite
Leptin - satiety hormone, inhibits hunger
Obesity - hormones not signalling correctly
Genetics
Leptin resistance - decreased receptor level, increase neuropeptide Y -> stimulates appetite -> TAG accumulation
Conditions - Prader-Willi, Bardet-Beidl, leptin deficiency, leptin receptor mutations
Influences by weight
Endocrine disorders
Hypothyroidism - little production thyroid hormones -> weight gain
Polycystic ovary syndrome - excess androgen
Crushings syndrome - too much cortisol, steroid medication for long time
Medications
Drug treatments - some antidepressants, steroids, sulphonylureas for diabetes, tamoxifen for breast cancer
Stop smoking - nicotine appetite suppressant, decreases metabolic rate
Cultural
Food outside home High fat intake - palatable, cheap Adverts + marketing Availability 24/7 Portion sizes Energy dense snacks/meals Lack healthy options Alcohol consumption
Behavioural
Meal patterns High fat diets Alcohol Physical activity - unsafe, weather, time Energy saving equipment TV viewing
Psychiatric disorders
Binge eating disorders Stress Emotions Rewarding with high fat + kcal treats Increased odds of mood disorder symptoms in obese
Psychology
Reasons for eating survey…
Hunger - least mentioned
Boredom Availability Tiredness Stress Habit Comfort Sociability
Environment
Obesity runs in family, e.g. dog + owner studies
External cue theory - triggers to eat
Learned behaviour - children model parents
