Obesity Flashcards
What is the definition of obesity?
Excessively high accumulation of body fat or adipose tissue in relation to lean body mass; amount of body fat includes concern for both the distribution of fat throughout the body and the size of the adipose tissue deposits; individuals usually at high clinical risk because of excess amount of body fat- BMI over 30
What are the parameters for BMI?
18.5 underweight
18.5-24.9 Healthy
25-29.9 Overwieght
30-34.9 Obese
35-39.9 Severe obesity
40-50 Morbid obesity
Which ethnic background have high BMI?
Asian
How does BMI relate to heart failure?
For every 1 increase in BMI, risk of heart failure goes up by 5% for men and 7% for women
What is causing obesity to increase?
Environmental not genetic changes- important because of complications e.g. diabetes
In what age group is BMI highest?
55-64
Which ethnic groups is BMI highest in?
Caucasian and Bangladeshi
In England, which part of the country has highest BMI?
Scotland and North England
What else affects BMI?
Smokers have lower BMI but greater central obesity Higher in social class 5
Why is being obese and overweight so common?
Food is cheap
Genetics turned on to eat to protect
Very few systems say stop
What are the costs of treating obesity?
49m
Other direct costs of upto 1.2bn
Other indirect costs of upto 1.07bn
Total cost= 3.7bn
What are the effects of obesity?
Known to lead to both chronic and severe medical problems Biggest killer- coronary heart disease Biggest impact on morbidity and quality of life- diabetes Osteoarthritis- weight bearing joints Infertility: in women as PCOS and men are most likely to be impotent Cancers: breast, endometrial Depression Stroke Sleep apnoea Gallstones Hypertension Gout
What are the two different types of obesity in terms of waist circumference?
Android (apple) vs gynoid (pear)
Android is centripetal obesity
Gynoid is where fat is deposited in bottom and legs
How is waist circumference measured?
Midpoint between lowest rib and iliac crest; ~1cm above navel and accuracy is difficult if BMI>35
What is higher levels of visceral adipose tissue associated with and how?
Increased insulin resistance
There is an impact on liver/glucose metabolism- lipid and insulin homeostasis is impacted. High excess visceral fat results in highest post-prandial insulin release as well as the highest 2 hour blood glucose reading
What is abdominal obesity associated with?
Increase in: insulin insensitivity Abnormal lipid profile Susceptibility to thrombosis Inflammation markers Endothelial function
Greater risk of CHD
What is the normal relationship between energy in, out and stored?
When weight stable, energy in= energy out + energy stored
When does weight gain occur?
Energy in exceeds energy out due to increased intake or decreased expenditure
What is adaptive thermogenesis?
Amount expended by digesting food.
What are the three components of daily EE?
Resting metabolic rate (RMR)- 50-70%
Thermic effect of food 5-15%
Energy cost of physical activity- 20-40%
What orexigenic/anabolic molecules are there?
Neuropeptide Y (NPY) Agouti gene related peptide (Agrp) Agouti-related transport (ART) Melanin-concentrating hormone (MCH) Dopamine
What anoretic/catabolic molecules are there?
Leptin receptor (LEPR) Pro-opiomelanocortin (POMC) Melanocortin receptor 4 (MCR4) Corticotrophin release hormone (CRH) Serotonin receptor subtype 2C (5-HT2C) Glucagon-like peptide 1 receptor (GLP-1R)
What genes are expressed in skeletal muscle regarding body weight?
Myostatin
Myogenin
Myogenic factors 4 and 5
What genes are expressed in brown adipose tissues regarding body weight?
Uncoupling protein 1 (UCP1)
What genes are expressed in white adipose tissue regarding body weight?
Leptin
Lipoprotein lipase
Fatty acid binding protein 4
Peroxisome proliferator-activated receptor gamma
What genes are expressed in gut regarding body weight?
Cholecystokinin receptor A
Glucagon-like peptide 1 (GLP-1)
What has been linked to increasing rates of obesity?
Energy intake has remained similar even decreased but there is increased inactivity (TV viewing and increased number of cars per household
Especially in lower social classes (don’t have higher energy/fat intake)
What has changed in diet over last 50 years?
Food is cheap
Energy between meals has increased
Energy density of food increased
Increased processing of food
What factors influence obesity risk?
Convincing evidence:
Regular exercise and high dietary fibre decrease risk; sedentary lifestyles and high intake of energy dense foods increase risk
Probable evidence:
Home and school environments supporting healthy food choices and breastfeeding may decrease risk; marketing of fast food and adverse socio-economic situation
Low GI foods decrease risk, protein has no effect
What are the effects of 10% weight loss?
Improves all aspects of metabolic syndrome, including: 50% fall in FBS (fasting blood sugar) 10% decrease in total cholesterol 15% reduction in LDL 30% fall in triglycerides 8% rise in HDL Improvement of BP by 10/20mmHg 20-25% reduction in mortality 30-40% reduction in diabetes related mortality 40-50% reduction in certain cancers
