Lecture 36 - Coordinating Metabolism: Obesity Flashcards
What is obesity?
A chronic complex disease defined by excessive
fat deposits that can impair health.
What does obesity influence?
Quality of living, such as sleeping, moving and
can have a negative impact on mental health.
What does obesity increase the risk of?
Type 2 diabetes, heart disease, stroke, impaired reproduction, liver and gall bladder disease, respiratory disorders and certain cancers.
New Zealand has the …. highest rate of adult obesity
Third
What are some potential ways of achieving weight loss?
- Reducing energy intake
- Increasing activities
- Increasing basal metabolism
What are some ways of reducing energy intake?
Calorie restriction, low fat diet, low carb diet, blocking
fat absorption (Xenical).
Why may diet weight loss be difficult to maintain?
The body resets to a lower basal metabolic rate
What are ketogenic diets?
Diets restricted in carbs
What do ketogenic diets promote?
The use of body fat and ketosis
What do ketogenic diets do to insulin secretion?
Reduce it
What do ketogenic diets do to your appetite?
Reduce appetite because proteins make you feel more full
What do keto diets based on saturated fats do?
Increase LDL levels
What is Xenical?
a pancreatic lipase inhibitor that reduces fat absorption , was heavily marketed for weight loss.
Why was Xenical not a favourable drug?
Due to moderate weight loss in trials and many side-effects
i.e. leakage, gas and fatty stools.
What are ways that basal metabolic rate can be increased?
- Increasing muscle mass because muscle is more metabolically active than fat and burns more ATP at rest.
- Uncouplers i.e. substances that uncouple OxPhos in the mitochondria, causing energy to be released as heat rather than generating ATP
What are examples of things that increase basal metabolism?
- Dinitrophenol (DNP) and FCCP (cause hyperthermia and organ failurei.e. very toxic).
- BAM 15 (safer and showing promising results in preclinical studies).
- Uncoupling protein activators i.e. Mirabegron which targets UCP1 in brown adipose (associated with some heart problems).
- Thyroid hormones (also associated with some heart problems).
What is Leptin and what does it do?
A hormone from adipose that signals to reduce appetite
What does GLP-1 from the gut do?
Signals to reduce appetite
What does Ghrelin from the stomach do?
Signals that the gut is empty and stimulates appetite
What are GLP-1 agonists good for?
Off-label weight loss
What is semaglutide?
A peptide similar to the endogenous hormone GLP-1
What effects does GLP-1 have in terms of weight loss?
Decreases gastric emptying
What does GLP-1 do in terms of diabetes?
- Less glucagon secretion
- more insulin secretion + biosynthesis
- More somatostatin secretion
- Less apoptosis
What may leptin deficiency cause?
Overeating
Does leptin resolve obesity?
Leptin doesn’t resolve obesity as it is leptin resistance that’s the problem
Can leptin deficiency occur in humans?
Yes but it is very rare
What are the competing paradigms of obesity pathogenesis?
Energy Balance model vs Carbohydrate-Insulin Model
What is the primary dietary driver in the energy balance model?
Energy dense, ultra-processed foods high in portion size, fat, sugar but low in protein and fibre
