11/14/24, 10\:53 AM Obesity

Obesity

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Obesity\: metabolic disease de
intake exceeding expenditure. WHO\: 4 million deaths annually, 1 in 4 UK adults, 1 in 5 UK children obese.
Diagnosis\: BMI >25 de
Aetiology\: complex, multifactorial, including behavioural/lifestyle factors, age, medications, hormonal issues, genetics.
Primarily due to prolonged energy imbalance.
Risk factors\: poor diet, lack of physical activity, underlying medical conditions (e.g., Cushing’s syndrome, PCOS),
medications (e.g., antidepressants, corticosteroids), socio-economic status, mental health issues, genetics (e.g., Prader-Willi
syndrome).
Metabolic syndrome\: group of risk factors (hypertension, hyperglycaemia, excess waist fat, hypercholesterolemia)
increasing risk of diabetes, stroke, heart disease.
Clinical features\: excess body fat, breathlessness, sleep apnoea, skin problems, osteoarthritis, hypertension, diabetes,
hyperlipidaemia.
History\: assess body weight history, dietary habits, physical activity, medical history, medication history, family history, social
history, socio-economic and cultural background.
Clinical examination\: measure BMI and central obesity (waist-to-height ratio, waist circumference). BMI categories\: healthy
weight (18.5-24.9), overweight (25-29.9), obesity class I (30-34.9), class II (35-39.9), class III (≥40).
Investigations\: fasting blood glucose, lipid pro
tests for underlying conditions as needed (e.g., dexamethasone suppression test, ultrasound for PCOS).
Management\: aim for 5-10% weight reduction. Non-surgical\: lifestyle changes (diet, exercise), orlistat (prevents fat
absorption), liraglutide (GLP-1 analogue, induces satiety). Surgical\: bariatric surgery (Roux-en-Y gastric bypass, sleeve
gastrectomy) for severe obesity (BMI ≥40 or 35-40 with co-morbidities).
Complications\: increased mortality and morbidity, cardiovascular disease, dyslipidaemia, diabetes, stroke, obstructive
sleep apnoea, cancer. Long-term management includes drug therapy (ACE inhibitors, dual antiplatelet therapy, beta-
blockers, statins) and lifestyle modi
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A comprehensive topic overview

Introduction

Obesity is a metabolic disease de
health. It is caused by prolonged imbalance where energy intake exceeds energy expenditure.
1,3
According to World Health Organisation (WHO), obesity is a global epidemic, with 4 million people dying annually due to
the disease. In the UK, 1 in 4 adults and 1 in 5 children are obese.
2
Body mass index (BMI) is the most widely accepted measurement of obesity, with individuals with a BMI of more than 25
classed as overweight or obese. 3
Alternative measurement tools include waist circumference and waist-to-height
circumference.
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Aetiology

The cause of obesity is complex and multifactorial. The main factors contributing to obesity are behavioural/lifestyle-
related, age, medications, hormonal issues, and genetics.
3,5
In simple terms, obesity is caused by an energy imbalance between calorie intake and expenditure over a prolonged
period.
4

Risk factors

The main risk factors for obesity include poor diet and lack of physical activity.
Other risk factors include\:
3,6
Underlying medical conditions\: Cushing’s syndrome, polycystic ovarian syndrome (PCOS), hypothyroidism and growth
hormone de
corticosteroids
Medications\: antidepressants (tricyclics, monoamine oxidase inhibitors, mirtazapine, atypical antipsychotics) and
Socio-economic status\: access to healthy food, education about healthy diet
Mental health\: depression, eating disorders (e.g. binge eating disorder, emotional eating)
Genetics\: rare genetic conditions, such as Prader-Willi syndrome and Bardet-Biedl syndrome, can result in obesity
Although genetics has been shown to play a role in regulating body weight, behavioural and environmental factors are
deemed the main contributors to obesity.
5
Metabolic syndrome
Metabolic syndrome is a term used to describe a group of risk factors including hypertension, hyperglycaemia,
excess fat around the waist, and hypercholesterolemia. It increases the likelihood of developing diabetes, stroke, and
heart disease.
7

Clinical features

A thorough history and examination are crucial to assess the cause of obesity and investigate for associated co-
morbidities.
The main feature of obesity is excess body fat and weight above average for an individual’s height.
Other clinical features are non-speci
Breathlessness
Sleep apnoea
Skin problems (e.g. intertrigo), increased risk of skin infections
Osteoarthritis
Hypertension, diabetes, and hyperlipidaemia.
8

History

Important areas to cover in the history include\:
9,10
Body weight history\: current weight, recent changes to weight and previous weight loss attempts
Dietary history\: current meals, frequency, quantity of meals
Physical activity history\: previous physical activity, current physical activity, actual and perceived barriers to increasing
physical activities
General medical history\: medical conditions (e.g. hypertension/diabetes, eating disorder screen, mental health, sleep
pattern)
Medication history
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Family history\: obesity, cardiovascular disease, PCOS
Social history\: alcohol, smoking history, recreational drug use
Socio-economic and cultural history\: occupation, living situation, history of trauma.
9,10
Discussing weight in the consultation
Individuals who are overweight may be sensitive about discussing weight. Patients do not want clinicians to assume
all their problems are weight related. It is important to listen to and address the patient’s concerns especially if their
presenting complaint is not weight related.
Despite the topic's sensitivity, as clinicians, it is important to address the subject of obesity as it can have serious
health implications.
Start the conservation about weight in a non-judgemental and respectful manner. Questions which can be helpful
include\:
" C o u l d I c h e c k y o u r w e i g h t a n d h e i g h t t o d a y b e f o r e y o u l e a v e"
" Y o u m e n t i o n e d k n e e p a i n , t h i s m a y b e r e l a t e d t o e x c e s s w e i gh t . W o u l d y o u l i k e t o t a l k a b o u t t h i s t o s e e i f w e c a n
h e l p y o u f e e l b e t t e r ?"

Clinical examination

Clinical examination should include\:
Measurement of BMI\: calculated by dividing an individual’s weight (kg) by height squared
Central obesity\: measured using a waist-to-height ratio or waist circumference
BMI is a rapid and inexpensive method that uses body weight and height to determine if an individual is healthy. An
individual who falls within the overweight or obese category is at an increased risk of health conditions such as heart
disease or diabetes.
Despite its usefulness, BMI as a single health unit is
and cannot di25
For example, a bodybuilder with high muscle mass and low
body fat can be classed as obese or overweight based on their BMI alone.
6
An alternative preferred measurement of obesity is waist circumference or waist-to-height circumference. This measures
a person’s central obesity or abdominal fat, which is a better determinant of future health risks than BMI. A waist
circumference above 94cm in males and 80 cm in females is deemed high risk.
21,25
When used in isolation, BMI and waist-to-height circumference are not perfect health measurements. However, within the
clinical setting, they are practical and useful in identifying patients who are obese.
23,24
Calculating BMI
BMI is calculated by dividing a person’s weight (kg) by the square of their height (m). Individuals who fall into the BMI
category of 25 to 29.9 and above are classed as overweight and obese\:
9
Healthy weight\: BMI of 18.5-24.9 kg/m
2
Overweight\: BMI of 25-29.9 kg/m
2
Obesity class I\: BMI of 30-34.9 kg/m
2
Obesity class II\: BMI of 35-39.9 kg/m
2
Obesity class III\: BMI of 40 kg/m 2
or greater
5 A's counselling approach
The 5 A ’s counselling approach is a useful mnemonic for counselling patients about weight in a general primary care
environment\:
9,13
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Assess\: identify patient at risk
Ask\:
" B e f o r e y o u l e a v e c o u l d I c h e c k y o u r w e i g h t t o d a y ?"
Advise\:
" O n e o f t h e b e s t w a y s t o l o s e w e i g h t i s w i t h s u p p o r t a n d { i n s e r t n a m e o f w e i g h t m a n a ge m e n t s e r v i c e } i s
a v a i l a b l e t o d a y . I c a n r e f e r y o u n o w i f y o u a r e w i l l i n g t o gi v e i t a go ?"
Assist in establishing interventions and securing goal attainment\:
The patient receives advice positively\: inform the patient of the next steps
Receptive but non-committal about a referral\: show acceptance of the patient’s wishes and acknowledge their
concerns
If the patient does not want to engage accept their decision and re-o
Actions\: Make the referral, document the conversation, follow up with the patient

Investigations

Individuals with obesity are at risk of developing other health conditions such as hypertension, heart disease, and
diabetes.

Laboratory investigations

Relevant laboratory investigations may include\:
9
Fasting blood glucose\: diabetes
Lipid pro
Liver function tests (LFTs)\: non-alcoholic fatty liver disease
Thyroid-stimulating hormone (TSH)\: hypothyroidism
Urea and electrolytes (U&Es)\: chronic kidney disease
SpeciCushing’s syndrome, TSH for hypothyroidism, and ultrasound for
polycystic ovarian syndrome can be requested if an underlying disease process is suspected.
9,11

Management

Obesity is managed by weight loss, with a target of a 5-10% reduction in body weight. 9
categorised into non-surgical and surgical.
Management of obesity can be

Non-surgical

Initial management of obesity includes lifestyle changes such as encouraging regular exercise, healthy eating, alcohol
recommendations and smoking cessation and therapy focused on behavioural changes.
9
Alternatively, drug treatment can be o
2 2 8.9
BMI of 30kg/m or 27kg/m with co-morbidities.
In the UK, orlistat and liraglutide are the only medications approved by National Institute for Health and Care Excellence
(NICE) to aid weight loss. They are recommended alongside a reduced calorie diet and increased exercise activity.
5,9
Orlistat is taken orally and works by preventing the absorption of dietary fat. 15
Side e
and loose stools.
16
Liraglutide is a glucagon-like peptide-1 (GLP-1) analogue and a diabetic drug used to treat weight loss. It works by
delaying gastric emptying and inducing early satiety resulting in an overall reduction in calorie intake and weight loss.
Side e
5,17
In a clinical trial, participants on liraglutide lost an average of 12% or more of their body weight compared to the placebo
18
group.

Surgical

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Bariatric surgery is weight loss surgery used to treat individuals who are severely obese and have a BMI of ≥40 kg/m 2
BMI between 35-40 kg/m 2 9,19
with co-morbidities such as type 2 diabetes or hypertension.
or a
Figure 1. Roux-en-Y gastric bypass
The most common types of bariatric surgery include the Roux-en-Y gastric bypass, sleeve gastrectomy, and gastric
bypass.
20
Weight loss surgery results in signi
healthy lifestyle changes.
6
Pre- and post-operative care involves input from a multi-disciplinary team of surgeons, dieticians, and a psychologist. The
role of the team is to ensure a patient is suitable for surgery and supported throughout their weight loss journey.
Preoperative requirements include blood tests to identify nutritional de
surgery.
Long-term follow-up is required to monitor nutritional de
activity advice.
3,26
Like any surgical procedure, there are risks such as anaesthetic risks, wound infection, and pulmonary embolism. The risks
speci
syndrome.
Dumping syndrome
Dumping syndrome describes a group of symptoms caused by food rapidly emptying or being ‘dumped’ from the
stomach into the small intestines. This results in undigested food within the small intestine that the body
di
27

Complications

Obesity is associated with increased mortality and morbidity.
Obesity-related complications include cardiovascular disease (e.g. hypertension, coronary heart disease), dyslipidaemia,
diabetes, stroke, obstructive sleep apnoea, and cancer.
8
Figure 2. Medical complications of
obesity
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References

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World Health Organisation (WHO). Obesity. W o r l d H e a l t h O r g a n i s a t i o n . Published in 2022. Available from\: [LINK]
National Health Service. Obesity. Published in 2019. Available from\: [LINK]
Yoo, Sunmi. Dynamic energy balance and obesity prevention. National Library of Medicine. P u b M e d C e n t r a l . Published in
2018. Available from\: [LINK]
Lin, Xihua and Li, Hong. Obesity\: Epidemiology, Pathophysiology and Therapeutics. National Library of Medicine.
P u b M e d C e n t r a l ( P M C ) . Published in 2021. Available from\: [LINK]
National Health Service, NHS. Metabolic syndrome. N H S . Published in 2019. Available from\: [LINK]
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National Institute for Health and Care Excellence (NICE). Obesity\: management. Published in 2022. Available from\: [LINK]
National Heart, Lung, and Blood Institute (NIH). NIH. Published in 2022. Available from\: [LINK]
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Reviewer

General Practitioner

Related notes

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Cushing's Syndrome
Diabetes Insipidus
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Growth Hormone De

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Contents

Introduction
Aetiology
Risk factors
Clinical features
Investigations
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