Obesity Flashcards
what is a metabolic syndrome?
having a combination of diabetes, hypertension and obesity.
It puts you at greater risk of getting coronary heart disease, stroke, myocardial infarction, all-cause mortality and cardiovascular mortality.
Different organisations have different definitions for metabolic syndrome.
They required the following combination of conditions:
explain the prevelance of obesity in the UK
Obesity rates are increasing
In the UK the prevalence of obesity in women in higher than men
Maternal weight gain and obesity in both parents can result in an increased likelyhood of obesity in the offspring due to epigenetic mechanisms
what are the two processes in obesity pathogenesis? (why do people develop obesity)
- Sustained positive energy balance
In order to gain weight, there needs to be a sustained positive energy balance
This is where energy intake > energy expenditure.
Therefore, treatment is based around the principle of creating a negative energy balance.
However, when you try to reduce energy intake your energy expenditure goes down.
Also, if you increase energy expenditure, appetite increases, and so does energy intake.
These two components are very interconnected. - Resetting of Body weight set point at an increased value
Body weight set point: the body will defend its current weight at a higher level than normal when we try and lose weight.
This occurs due to genes and biological factors.
Biological factors:
When we try to lose weight:
The body reacts by changing hormone levels so hunger hormones increase and the satiety hormone levels go down.
This encourages energy intake.
(These remain even after weight regain)
Resting energy expenditure also drops after weight loss.
The body goes into an energy saving mode to stops weight loss.
This is why most people regain weight after weight loss - the body is defending its current weight.
what factors contribute to obesity?
Lots of factors contribute to obesity and they interact with one another.
Examples include: Media, social, economic, food, activity, biological and medical factors.
These factors impact the hypothalamus’ ability to regulate energy homeostasis.
They therefore contribute to the development of obesity.
We need to address these factors to combat obesity in the UK.
what are the 2 ways to address obesity?
- Societal changes
address the things above - Individual changes
Lifestyle and behavioural changes
Medication to help lose weight
Surgery e.g. bariatric surgery
what is BMI?
key figures?
You can use BMI to measure obesity - lots of data to support the link between a high BMI and higher chance of diseases
As BMI increases there is an increase age adjusted risk of Type 2 diabetes.
BMI = weight [kg] / height2 [m]
Obesity defined as BMI > 30kg/m2
Morbid obesity defined as BMI > 50kg/m2
strengths of BMI?
Cheap
Quick
No special equipment
Do it at home
Very useful at population level
Weaknesses of BMI?
Does not differentiate between muscle mass or fat mass
Also, not all fat is the same.
Having higher central obesity, around the waist increases chance of health disorders, however having body fat around hips and thighs is associated with reduction in the risk of diseases.
how are BMI categories variable?
It is important to know S. Asians are classified as being obese at a lower BMI than white Europeans.
S Asians have obesity at a BMI of 25 not 30 (WE) and are overweight at a BMI of 23.
The reason why this is lower is that if you take a S Asian and European with same BMI you will find s Asian has much more visceral fat and more insulin resistance so has more obesity related complications.
what is central obesity?
what does it lead to?
Central obesity leads to insulin resistance
Insulin resistance: the body needs to secrete more insulin to achieve a similar degree of glycaemic control.
As insulin resistance increases the higher the risks of health problems e.g Hypertension, cancer, Coronary heart disease, T2D and strokes.
are glucose levels the same for obese and lean people?
Glucose levels are the same for obese and lean people but there is a higher amount of insulin being secreted in people who are obese to achieve these same levels.
how is adipose tissue mass regulated?
Insulin causes more adipocytes to develop -insulin is an adipocyte stimulating factor
It promotes proliferation & differentiation of preadipocytes to form mature adipose tissue –> Increases lipid accumulation
Therefore, weight gain is a common effect of people who take insulin
how do you manage obesity?
what are the benefits of 5-10% weight loss?
We only need to lose a small amount of weight to achieve significant health benefits.
Benefits of 5-10% weight loss:
Reduction is risk of type 2 diabetes
Improvements in blood pressure
Reduction in CV mortality
Improvements in blood lipid profile
Improvements in severity of obstructive sleep apnoea
Improvements in health-related quality of life
what are the levels of intervention to tackle obesity?
People with low levels of obesity, low number of comorbidities and a low waist circumference are given lifestyle advice in order to help tackle their obesity.
As the three factors above increase, doctors begin to offer the following interventions in this order:
1. Diet and physical activity
2. Consider drugs to help lose weight
3. Consider surgery
You use the interventions in combination.
E.g., someone on the list for surgery will still be taking drugs, dieting and engaging in physical activity.
what are the weight management principles?
- First you need a strong partnership with your patient.
There should be a shared decision-making process between patient and doctor.
However, the patient has the final decision of what treatment they wish to have. - You should know your patient
Understand why they want to lose weight and how can you use this information to help motivate them further.
Understand what barriers are there in a patients life that prevent them from losing weight. - Avoid obesity stigma.
Stop judgments and prejudice.
People with obesity are not lazy.
There are a lot of biological factors causing obesity, not just lack of exercise. - Factors to consider when choosing treatment options
(The treatments available are - lifestyle and behavioural changes, pharmacological treatment and surgery surgical treatment)
a. We need to know why the patient wants to lose weight and why now
b. The disease severity
c. Patient needs (see below):
- How quickly do you need to lose weight and how much weight do you need to lose? –> Rapid vs slow weight loss requires different interventions
d. Previous unsuccessful treatments: Don’t repeat the unsuccessful treatments and help patients reflect why these treatments were unsuccessful so they don’t repeat bad habits.
e. Underlying cause of their obesity
f. Look at the evidence base for the long-term weight maintenance that you are recommending.
For the two examples below the treatment will be different i.e., second one will get bariatric surgery because the drop in weight needed is higher and the woman is younger so we have time to prep and have surgery before attempting fertility.
First women BMI is not high above 35 however the age is close to cut off for funding so we need to lose weight quickly e.g very low energy diet or pharmacotherapy.
We need to understand underlying causes of obesity when deciding treatment.
- We need to think about the causes and then address all of them to help patient to lose weight.
There are usually multiple causes.
explain disease staging
It is important that weight management treatment is not purely weight centric.
Weight management needs to focus on improvements of quality of life and the reduction in complications as well.
This is why we use a staging system
The stage you are at helps plan your treatment
You want to progress down the stages
explain the graph
With EOSS scale there is a strong correlation between the stage you are at and mortality
Using simply BMI does not show as strong a correlation
what are the pharmacological options for weight management?
The mode of actions of drugs include:
Energy wastage (don’t extract as much energy from your food as you normally would
Appetite suppression
Orlistat:
Lipase inhibitor: It stops digestion of lipids resulting in lipids going out in stool via GI tracts.
This results in energy wastage and therefore reduced energy intake.
Saxenda:
Works by stimulating satiety and stimulating fulness via the hypothalamic energy homeostasis centre
Greater weight loss occurs when there is combined therapy e.g lifestyle interventions with pharmacotherapy.
Continuing medication also prevents weight regain after it is initial lost
how does bariatric surgery work?
what does it result in?
Gastric band result in 20% weight loss
Sleeve gastrectomy and gastric bypass results in 40-45% weight loss
Bariatric surgery has long term evidence showing it to be the most successful way to achieve weight loss in the long term
There is an initial weight regain but the weight stabilised at a much lower level.
Incidence of developing metabolic complications e.g., CVD, hypertension, mortality and heart failure incidence is much lower in patients who have received bariatric surgery in comparison to standard care.
Bariatric surgery has much higher rate in achieving diabetes remission compared to standard care.
However, as time after diagnosis goes on remission rate goes down.
Highest remission rates occur with people who have had diabetes for shortest time.
So, it is important to intervene early.
