Obesity Flashcards
% of men and women overweight in the UK
44% men
34% women
% of men and women obese in the UK
23% men
23% women
what are the components of daily energy expenditure in sendentary person
8% thermic effect of feeding
17% energy expenditure of PA
75% resting energy expenditure
what are the components of daily energy expenditure in a PA person
8% thermic effect of feeding
32% energy expenditure of PA
60% resting energy
relationship between EE and fat free mass
as fat-free mass increases REE increases
e.g obese have greater REE
norml BMI
18.5-24.9
overweight BMI
25-29.9 kg/m2
obesity BMI
obese 1 - 30-34.9
obese 2 - 35-39.9
obese 3 - >40
relationship between BMI and %body fat
as BMI increases, body fat increases in general
realtionship between BMI and CV mortality
as BMI increases risk increases
3 step increases for each chnage in BMI classification
obesity and diabetes
greater prevealance of T2D in obese
excess body fat leads to insulin resistnce
possible genetic predisposition
why does excess body fat lead to insulin restistance
Adipose tissue creates demand for insulin – increase fat deposition
Chronic high blood sugar down regulates insulin receptors
Fats block insulin receptors, leading to insulin resistance
Fat tissue, especially visceral fat, has a role in promoting diabetes
obesity and hypertension
often associated
for every 10% increase in body weight, systolic BP increases 6.5mmHg
6x more prevelant in obese
obesity and blood cholestrol
each kg of fat, approximatley 20mg/dl of cholestrol is synethiesised
obesity and respiratory disease
Burden of excess fat on thorax makes breathing more difficult and reduces lung volume
Hypoxia develops initially , hypercapnia can also develop reduced respiratory drive
Sleep apnea and snoring are common
obesity and orthopeadic problems
Strong positive correlation between arthritis and obesity
Every 5kg ↑ in weight, increased knee arthritis by 35%
Energy cost of movement is much greater in the overfat
Sedentariness becomes habitual leading to atrophy of muscles
fat but fit
If you are over fat then being aerobically fit helps reduce risk
Mortality rates are low in obese / overweight if fit
Metabolically healthy but obese (MHO) phenotype
Should not assume just because obese they are unhealthy 15-30% obese are MHO
CVD risk appears to be no higher in MHO compared to normal healthy normal weight adults
Causes of obesity
Genetic
Metabolic
Over eating
↓ Physical activity
Cause of obesity: Genetic
Faulty Leptin production or resistance
Leptin a hormone, which ↓ appetite, secreted from body fat in proportion to the number of body fat stores.
An increase in body fat causes an increase in leptin production, which suppresses intake, which should lead to a decrease in fat and therefore leptin production.
Cause of obesity: Meatabolic Factors
Some obese persons have a lower metabolic rate
Can be caused through defects; hypothyroidism, Cushing’s syndrome (overproduction of cortisol).
Metabolic control of appetite may go wrong
Food intake is controlled by orosensory, gastrointestinal & neuroendocrine factors.
Defects in these pathways may lead to dysregulation of appetit
effects of parents on child weight
If both parents obese, 70-80% chance of child being obese.
Mother more critical.
If neither parent obese, 14% chance of being obese
what is the set point theory
Body defends a certain weight like a thermostat regulates temperature
Normally returns back to that weight
Passive consumption
Individuals allowed to eat ad-lib diets that contain different fat levels will consume more energy on the high fat diet than on high CHO diet
- People tend to consume the same weight/volume of food at each meal and are unable to sub-consciously adapt to varying energy densities
- The same volume of a high fat (energy dense) meal will provide many more calories than the same volume of a high CHO meal
benefit of a 10% weight reduction
↓ > 20% total mortality (diabetes related and cancer deaths) ↓ 10 mmHg systolic BP ↓ 20 mmHg diastolic BP ↓ fasting blood glucose ↓ 10% total cholesterol ↓ 15% LDL cholesterol ↓30% triglycerides ↑8% HDL cholesterol
