Obesity Management Flashcards
What is the definition of obesity?
chronic, life-threatening disease
An excessive accumulation of body fat sufficient to im0pair health
What are some things obesity can lead to? (5)
Heart disease Stroke Sleep apnoea Cancer Liver disease
What causes obesity?
Individual lifestyle choice
Society: Abundant, cheap, palatable food No need for physical activity at home or work
Genetic factors
What is energy balance?
“State in which energy intake, in the form of food and /or drinks, matches the energy expended”
What is positive energy balance? (2)
Energy in is greater than energy out Resulting in weight gain
What is negative energy balance? (2)
Energy in is less than energy out
Resulting in weight loss
What are three components of daily energy expenditure?
Thermic effect of feeding
Energy expenditure of physical activity
Resting energy expenditure
What are the factors that can influence Resting energy expenditure (REE)? (8)
- Body composition
- Gender
- Age
- Height, Weight
- Hormones e.g. Thyroid
- Body temp
- Pregnancy
- Fasting/Malnutrition
What does the Barker hypothesis state?
“Adverse environments in foetal life and early childhood establish increased risk of disease in adult life”
When does maladaptation occur?
When there is a Mismatch of poor prenatal environment and rich postnatal environment
What % of heritability of obesity?
40-60%
What can genetic factors influence?
body size and shape
body fat distribution
metabolic rate
brain chemistry
What is thrift metabolism?
Cycle of feast and famine
Thrifty metabolism gene allows for increase fat storage to protect against famine
What is the % of a child becoming obese if parent/s are?
No obese parents = 10%
1 obese parents = 40%
2 obese parents = 80%
What is the obesity gene?
FTO - shows fatty foods more tempting and altered levels of the hunger hormone, ghrelin
What is the FOOD4ME study?
A study that aims to:
mimic an internet-delivered personalised nutrition service, with blood analysis and DNA home testing kits
What are the two feedback signals for energy homeostasis?
Short term: operates meal to meal basis, determine amount of food ingested in single meal
Long term: works over weeks/years to regulate energy intake & expenditure
Modulated by adipose tissue mass; major mediators are leptin and insulin
What is Grelin? and where is it released from?
A hormone which increases food intake
Released from GI tract - gastric mucosa
What is Leptin? and where is it released from?
Hormone regulates long term body weight rather than short term appetite
Released from Adipose tissue
When does Leptin peak at? Where does it act?
Diurnal variation: peak at night
Acts in the CNS to suppress food intake
Which neurons does Ghrelin stimulate?
Stimulates NPY neurons
Which disease has high levels of Ghrelin?
Prader-Willi syndrome - rare condition. It’s caused by a genetic defect on chromosome number 15, which happens purely by chance
What hormones does the adipose tissue excrete and what do they do? (6)
Aromatase, which is involved in sex hormone metabolism.
TNF alpha, IL-6 and leptin, which are collectively termed ‘cytokines’ and are involved in sending messages between cells.
Plasminogen activator inhibitor-1, which is involved in the clotting of blood.
Angiotensin, which is involved in blood pressure control.
Adiponectin, which improves the body’s sensitivity to insulin and so helps to protect against developing type 2 diabetes
Lipoprotein lipase and apolipoprotein E, which are involved in storage and metabolism of fat to release energy.
What are the mechanisms by which adipose tissue may influence cancer risk of obesity and cancer?
Production of sex steroid hormones
Effects on insulin sensitivity and production of insulin-like growth factors
Actions on other hormones in adipose tissue (e.g., leptin, adiponectin)
*Increases in oxidative stress and chronic low-grade inflammation that affect the body’s immune response
What are the THREE treatment options for obesity? give examples of each
Lifestyle modification e.g. behaviour change
Medical treatment e.g. Orlistat, Incretin mimetics (GLP-1 Agonists)
Surgical treatment e.g.
Gastric band (Lap band)
Gastric bypass
Vertical Sleeve gastrectomy
What are the benefits of a 10% weight loss?
Mortality: 20-25% fall in overall
30-40% in diabetes related deaths
40-50% fall in obesity-related cancer deaths
Diabtetes: Up to 50% fall in fasting blood glucose
Reduces risk of developing diabetes by over 50%
Lipids:Fall of 10% total cholesterol, 15% LDL and 30% TG; Increase of 8% HDL
BP:10 mmHg fall in diastolic and systolic pressures
How does Orlistat work? (120mg)
Reduces fat absorption
Eating fat causes anal leakage
Can cause substantial weight loss
How does Phentermine work?
Suppress appetite
May help but results in dry mouth, nausea and constipation.
What is sleep apnoea?
Intermittent cessation of breathing during sleep due to the collapse of the pharyngeal airway, resulting in multiple apnoeic or hypopnoeic events
