Obestiy Flashcards
What is obestiy?
- Too much body fat
- Too much fat in the wrong place
- Casued by chronic positive energy balance due to:
1. Too much energy intake
2. And/or too little energy expenditure
How do we asess obesity?
- BMI, weight/height
- 25-29.9 pre-obese
- 30-34.9 Grade 1–Moderate (risk of co-morbidity)
- 35-39.9 Grade 2–Severe
- 40+ Grade 3–Very severe
What are the consequences of obesity?
Obesity is a major risk factor for CHD
Also:
* Inc BP
* Inc plasma cholesterol levels
* Inc risk of type II diabetes
- All these are additional factors for CHD
- Inc NHS costs
- Also inc risks of many cancers
How to treat Obesity?
- Weight loss target- 5-10% of original weight with a max weekly loss of 0.5-1Kg
- Dietetic Treatment
- Very low calorie diet
- Drugs
What is Dietetic treatment?
- Based on energy balance equation
- Energy input-energy consumption=Energy balance
- In order to lose weight, energy balance must be negative
What are very low calorie diets(VLCDs)?
- Commercially-prepared diet
- Medical supervision only
- For very obese patients who need to lose weight quickly
- Typically 400-600Kcal/day for several days/weeks(But max 12 weeks)
What are other dietary approaches?
- Individualised modest energy restrictive diet
- Aim to provide 500kcal/day less than calculated amount
- Slower weight loss, based on healthy eating guidelines
What are currently licenced drugs?
- Orlistat
- Liraglutide
- Mysimba
What is Orlistat?
- Tetrahydrolipostatin
1. Synthesised derivative of lipostatin - Inhibits Gastric and Pancreatic lipase
- Irreversible inhibitor
- Forms covalent bonds with serine residues in the active site of lipases
- Minimal absorption
- Needs to be taken before each main meal
- ~30% inhibition of lipases at normal therapeutic doses (lose 200Kcal per day)
- Needs to be combined with low fat diet
What are the side effects of Orlistat?
- Steatorrhea-Fatty, foul smelling faeces
What is OTC Orlistat?
- Reduced dose- 60mg tds
- Max 6 months
- Combined with red fat diet
- BMI>28
What controls appetite?
- The hypothalamus controls appetite.
What are GLP1 agonists? (Saxenda & Wgovy)
Liraglutide and semaglutide are glucagon-like peptide-1 (GLP-1) receptor agonist
S.c. Injection
* Appetite suppression–effects in the hypothalamus
* Inc secretion of neurotransmitters POMC & CART involved in appetite suppression
* GLP-1 can also reduce hugh fat food intake by suppressing dopamine signalling–effect on reward pathways
What is Mysimba?
- Combination of naltrexone & bupropion
- Effects on reward pathway
- Bupropion:
1. Dopamine and noradrenaline reuptake inhibitor.
2. Inc levels of these neurotransmitters in the brain
3. Greater activation of receptors - Naltrexone: Opiod Receptor antagonist
What is the mechanism of Mysimba
- Mechanism not well understood. Possibly:
1. Bupropion activates appetite suppressing neurons
2. Naltrexone: Prevents endogenous negative feedback pathways that would normally counteract this effect