Treatment Guideline Chart
Obesity is a chronic, progressive and relapsing medical condition characterized by the accumulation of abnormal or excessive body fat that impairs health.
Causes of obesity are multifactorial with complex interactions.
Treatment goals include addressing the principal cause of weight gain and focusing management on both weight loss and patient-centered health outcomes.
A multidisciplinary approach, that is a combination of dietary change, physical activity and behavioral modification, is recommended.

Obesity Diagnosis


  • Elicit the following in the history: Weight history, eating habits, physical activity, alcohol consumption, smoking, sleep hygiene, underlying diseases or conditions that hinder physical activities or weight loss, cultural and environmental factors affecting weight
  • Exclude secondary causes of obesity such as medications (eg Insulin, Nateglinide, Repaglinide, Risperidone, Sertindole, Olanzapine, Clozapine, Mirtazapine, Valproate, Gabapentin) or history of genetic or endocrine disorders (eg hypothyroidism)
  • Detect potential comorbidities [eg type 2 diabetes mellitus (T2DM), hypertension, dyslipidemia, obstructive sleep apnea (OSA), nonalcoholic fatty liver disease (NAFLD), cardiovascular disease (CVD), osteoarthritis (OA)]
    • Its presence may affect the treatment decisions and outcomes
  • Assess mental status (eg patient’s self image, general mental health, stress factors, eating disorder, presence of depression and other mood disorders, substance abuse) and psychosocial barriers
  • Detect pregnancy in women
    • Not usually recommended for weight loss program
  • Family history (eg obesity, presence of CVD, hypertension, DM, dyslipidemia, obesity-related cancer, thyroid disease)

Physical Examination

  • Blood pressure (BP) measurements in both arms
  • Check for evidence of thyroid disease, Cushing’s syndrome, hypogonadism, dysmorphism and signs of insulin resistance (eg acanthosis nigricans) 


  • Body Mass Index (BMI)
    • Measures weight relative to height
    • Indicates total body fat content
    • Helps predict future health status as raised BMI increases cardiovascular events or deaths, total mortality, DM, sleep disorder, osteoarthritis and certain cancers (eg endometrial, breast, colon, kidney, esophagus)
    • Done annually for screening and as needed for management
    • Calculated by the formula: BMI = weight (kg)/[height (m)]2
      • Asian countries have lower BMI cut-off points for overweight and obesity than the World Health Organization (WHO) BMI values
    • Calculation is for all age groups; BMI percentile for age is used in children <18 years old to determine the healthy weight status 
  • Waist Circumference
    • Useful measurement of intra-abdominal fat content before and during weight loss treatment
      • Measured at the approximate midpoint between the superior iliac crest and the lower margin of the last rib
    • Measurement of choice for classifying central obesity and clinical risk
    • An increased waist circumference is associated with an increased risk for T2DM, dyslipidemia, hypertension, NAFLD and CVD in patients who may not be considered obese by conventional BMI criteria

Lab and Diagnostic Tests

  • To assess comorbidities associated with obesity
    • Lipid profile [eg low-density lipoprotein cholesterol (LDL-C), high-density lipoprotein cholesterol (HDL-C) and triglyceride (TG)]
    • Fasting glucose level, A1C, thyroid function tests
    • Uric acid, liver function (hepatic enzymes), renal function
    • Urine free cortisol levels (perform in patients with signs of Cushing’s syndrome)
    • Tests to rule out polycystic ovarian syndrome (only if symptomatic)
    • Electrocardiogram (ECG) if >50 years old or with risk factors
    • Chest X-ray (not routinely recommended) 
    • Polysomnography and other sleep studies in patients at risk for sleep apnea (eg suggestive signs and symptoms such as excessive daytime sleepiness, snoring, increased neck circumference or a high STOP-Bang score) 


Risk Factor Assessment

Identify absolute risk status based on the presence of the following:

  • Disease Conditions
    • Coronary heart disease (CHD)
    • Atherosclerosis
    • Hypertension
    • T2DM
    • OSA
    • Dyslipidemia
  • Other Obesity-Associated Diseases
    • Polycystic ovary syndrome (PCOS)  
    • Infertility  
    • Male hypogonadism
    • OA
    • Asthma
    • Heart failure
    • Gallstones
    • Urinary stress incontinence
    • NAFLD
    • Gastroesophageal reflux disease (GERD)
    • Proteinuria
  • Cardiovascular Risk Factors
    • Cigarette smoking
    • Hypertension
    • Hyperlipidemia
    • Impaired fasting glucose and impaired glucose tolerance
    • Family history of premature CHD [eg myocardial infarction (MI) or sudden death in father/male 1st-degree relative at ≤55 years or mother/female 1st-degree relative at ≤65 years]
    • Age ≥45 years for men or age ≥55 years or postmenopausal for women
  • Others
    • Physical inactivity
    • Elevated serum TG (>2.3 mmol/L) and decreased HDL-C


WHO Classification WHO BMI Cut-off Points (kg/m2) Risk of Comorbidities Asian BMI Cut-off Points (kg/m2)
Underweight <18.5 Low but increased risk of other clinical problems <18.5
Normal 18.5-24.9 Average 18.5-22.9
Overweight/Pre-obese 25.0-29.9 Increased 23.0-27.4
Obese Class I 30.0-34.9 Moderate 27.5-32.4
Obese Class II 35.0-39.9 Severe 32.5-37.4
Obese Class III ≥40.0 Very severe ≥37.5
Race High-Risk Waist Circumference (cm)
Men Women
Asians ≥90 ≥80
Caucasians ≥102 ≥88

  • Presence of obesity warrants assessment for obesity-related comorbidities (ORCs) which should be graded according to severity if present   
    • Treatment approach and goals are tailored according to the presence of ORCs and their severity   
  • Presence of any ORC also warrants assessment for obesity and its severity if not the presenting condition or the condition consulted for  

Severity of Obesity    

  • Stage severity of obesity based on complication-specific criteria
BMI (kg/m2) Clinical Component Disease Stage Complications
<25 (<23 in certain ethnicities) Normal weight None
25-29.9 (23-24.9 in certain ethnicities) Evaluate for presence or absence of adiposity-related complications and severity of complications
  • Asthma/reactive airway disease
  • CVD
  • Depression
  • Dyslipidemia
  • Female infertility
  • GERD
  • Hypertension
  • Male hypogonadism
  • Metabolic syndrome
  • OSA
  • OA
  • PCOS
  • Prediabetes/T2DM
  • Urinary stress incontinence
  • Overweight Stage 0 None
    ≥30 (≥25 in certain ethnicities) Obesity Stage 0 None
    ≥25 (≥23 in certain ethnicities)

    Obesity Stage 1 ≥1 mild-moderate complications
    Obesity Stage 2 At least 1 severe complication
    *Modified from: American Association of Clinical Endocrinologists (AACE) and American College of Endocrinology (ACE) comprehensive clinical practice guidelines for medical care of patients with obesity. Endocr Pract. 2016 Jul;22 Suppl 3:1-203.


    • Alternatively, the Edmonton Obesity Staging System or the King’s Obesity Staging Criteria can be used to assess the impact of obesity on physical and psychological health and function; helps determine the benefit of treatment

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