obesity Flashcards
what is obesity?
Obesity is a chronic, life-threatening disease
An excessive accumulation of body fat sufficient to impair health
Independent risk factor or aggravating agent for at least 30 common health conditions
classification of obesity
normal - BMI - 18.5-24.9
overweight -BMI - 25-29.9
obese - 30-34.9
severe obese- 25-39.9
morbidly obese - equal or over 40
what other conditions can obesity effect
- heart disease
cancer
stroke
liver disease
reproductive complications
depression/anxiety
sleep problems
asthma
type 2 diabetes
what causes obesity
inidivual life chouce
society - cheap food, adverts, availaibity, work from home
determined by genetics
how can you regulate weight
energy intake = energy outake
what does energy balance mean
negative
positive
“State in which energy intake, in the form of food and /or drinks, matches the energy expended”
Positive energy balance
Energy in > energy out
Results in weight gain
Negative energy balance
Energy in < energy out
Results in weight loss
what is yo-yo eating and BMR
Weight loss
Loss of muscle mass
Reduced BMR
Reduced requirements
what is the barkers hypothesis
“Adverse environments in foetal life and early childhood establish increased risk of disease in adult life”
Under-nutrition in gestation induces programming of the pancreatic beta cells, muscle, liver, adipose tissues and neuroendocrine axis
Mismatch of poor prenatal environment and rich postnatal environment leads to maladaptation
Increases risk of obesity, glucose intolerance and coronary heart disease in adult life
evidence for genetic influence
familial aggregation
twin studies
Familial aggregation
Familial clustering of obesity in families
Twin studies
Greater concordance among monozygote compared with dizygote twins
what does genetic factors influence
body size and shape
body fat distribution
metabolic rate
brain chemistry
what does thritfy metabolism gene allow
what is it
Thrifty metabolism gene allows for fat storage to protect against famine
Cycle of feast and famine
Those that were better at fuel storage or utilization more likely to survive during famine
Over generations, we developed genetically to be exceptionally efficient at the intake and utilization of fuel
probability of getting obesities
no parets obese
1 parent
both parent
no parent - 10 %
1 parent - 40%
2 parents - 80%
what is the energy homeostatis system
The energy homeostasis system:
is precisely regulated across the lifetime of an individual
promotes stability in the amount of body energy stored in the form of fat
2 types of feedback signals
There are two types of feedback signals:
Short-term
Meal-to-meal basis - determines amount of food ingested in a single meal
Satiety factors include nervous signals initiated in the GI tract
Long-term
Work over periods of weeks to years to regulate our energy intake & expenditure
Modulated by adipose tissue mass; major mediators are leptin and insulin
what is leptin
Secreted by adipocytes in proportion to the amount of stored fat
Primary way brain knows how much body fat is stored
Regulates long term body weight rather than short term appetite
Diurnal variation: peak at night
Acts in the CNS to suppress food intake