Energy balance and obesity W1 Flashcards
Energy balance for weight loss
Less food intake and more energy expenditure (exercise)
Energy balance for weight gain
More energy intake and less energy expenditure
What percentage of energy intake is used for heat loss?
50%
What percentage of energy intake is for digestion/absorption?
5 to 10%
What is the rest of the energy intake used for?
ATP
Regulation of food intake – physiological factors
Hormones, peptides, energy stores, hypothalamus
Regulation of food intake – genetic factors
Leptin, MC4R
Regulation of food intake – psychological factors
Mood
Regulation of food intake – social/environmental factors
Lifestyle, work
How many calories per day could produce 2 kg of weight gain per year?
50 kcal per day
What is leptin?
- Sensor of body fat
- reduces food intake
- expressed in fat cells
- Synthesis is increased by a glucocorticoids, insulin, and oestrogen
- Synthesis is reduced by B – adrenal receptor agonist
- Target the hypothalamus
- Produced by adipose issues
What are the two groups of neurons that have opposing actions in Lepton’s targets in the hypothalamus
Neuropeptide (NPY)and agouti related peptide (AGRP)
Pro-opiomelanocortin (POMC) and a-melanocyte-stimulating hormone (a-MSH)
Neuropeptide (NPY)and agouti related peptide (AGRP)
Work together to increase food intake and decrease energy expenditure
Energy in is increased energy out is decreased
You are more hungry
Activated by reduced leptin
Pro-opiomelanocortin (POMC) and a-melanocyte-stimulating hormone (a-MSH)
Work together to decrease food intake and increase energy expenditure
Energy out is increased and energy and is decreased
Less hungry
Activated by increased Lepine
Leptin deficiency
Very rare only in two families
Severe childhood obesity
Given recombinant leptin resolved obesity
Leptin mutation
Mutations in the leptin receptor are very rare (have Lepine but cannot bind)
Severe childhood obesity
Mutations prevent leptin entering the cell
Recombinant leptin doesn’t help as it still won’t bind or respond
Lipton levels linked with obesity
Leptin levels are not lower in obese individuals
Different behaviours
Ordering takeout
Watching telly
Eating out
What is BMR?
Basil, metabolic rate
The amount of energy suspended by the body to maintain physiological functions over a period of 24 hours
Subject line at physical and mental rest in a comfortably warm environment at least 12 hours after the last meal
Is determined by body mass and so varies with weight, composition, age, gender, genetic factors
Are the main components of energy expenditure?
Meal induced thermogenesis
Increase the metabolic rate following food consumption
Thermic effect for fat is lower than protein or carbohydrate
Physical activity of 20 to 40% of daily expenditure
Inheritability of obesity
Can be as high as 30 to 40%
Gene disorders of obesity
Single gene disorders approximately 200 associated with obesity
Body mass index
Weight in kilograms/height in metres squared
Underweight BMI
< 18.5
Desirable BMI
18.5 to 24.9
Overweight BMI
25 to 29.9
Grade one moderately obese BMI
30 to 34.9
Grade 2 severely obese BMI
35 to 39.9
Grade 3 morbidly obese BMI
> 40
How many people in England are overweight or obese?
Over 68% adult men
Over 59% adult women
Overweight children in the UK
One and five children in reception are overweight or obese
One and three children in year six is overweight or obese
Complications associated with obesity
Sex hormone imbalance
- Hormone dependent tumours
Increased free fatty acids
- Insulin resistance
- Hypertension
- Dyslipaemia
- Type two diabetes
- CVD
Mechanical stress
- Sleep apnoea
- Osteoarthritis
- Low back pain
- Shortness of breath
Weight management UK recommendations
Reduce energy intake by 600 kcal a day
Healthy balanced diet
150 minutes of more activity per week
