Aspects of Obesity Flashcards
What is obesity due to?
Energy imbalance = people take in too much energy and/or do too little exercise
What is the thrifty genotype?
Genotype evolved by humans that optimised response to feeding opportunities = maladaptive in an environment where access to food is constant
What is the variant of the FTO gene implicated in?
BMI and also predisposes to childhood obesity = affects food intake by making people eat more
What are the health consequences of obesity?
Hypertension, cancer, gallbladder disease, renal failure, stroke, heart failure, atherosclerosis, type 2 diabetes
What may the link between obesity and cancer be due to?
May be mediated by high levels of insulin and/or oestrogen in obesity
What are the co-morbidities of obesity?
Osteoarthritis, back pain, asthma, sleep apnoea
What does adipose tissue secrete?
Adipocytes secrete adipokines = leptin, CRP, TNF alpha, adiponectin, IL-6, cortisol, oestrogen
What does leptin do?
Tells body how thin you are = if you don’t have leptin/leptin receptors then the body thinks you’re starving and acts accordingly
How is obesity linked to atherosclerosis?
Adipocytes and macrophages share functions = in obesity adipocytes secrete cytokines and macrophages accumulate fat, becoming foam cells which are found in atherosclerotic plaques
What are some dietary interventions for obesity?
Hypocaloric diets = take in less calories than being used
Options = portion control/calorie counting, low carb/fat, very low calorie diet, meal replacement
What is a drug commonly used to treat obesity?
Orlistat
How does orlistat work?
Block absorption of dietary fat by inhibiting lipase, up to 1/3 of ingested fat excreted into faeces
What are the types of bariatric surgery?
Restrictive or malabsorptive = banding and sleeves are restrictive, bypass is both restrictive and malabsorptive
What are the most common bariatric surgeries done in the UK?
Adjustable gastric band = simplest, prone to slipping
Roux-en-Y gastric bypass
Vertical sleeve gastrectomy
How is the resting metabolic rate (RMR) calculated?
Amount of energy expended at rest - minimum energy consumption
What contribute to the resting metabolic rate?
Fat mass and fat free mass
How is the RMR affected in obesity?
Higher in obesity and falls with weight loss = observed fall in RMR often exceeds predicted due to adaptive thermogenesis
What does adaptive thermogenesis do?
Acts as a brake to prevent further weight loss
What is the link between the RMR and weight loss?
The lower the RMR, the harder it is to lose weight
