Obesity is defined by the World Health Organization (WHO) as abnormal or excessive fat accumulation that may impair health1
≥ 18.5 and < 25.0
≥ 25.0 and < 30.0
Obese, class I
≥ 30.0 and < 35.0
Obese, class II
≥ 35.0 and < 40.0
Obese, class III
BMI=the weight in kilograms divided by the square of the height in metres (kg/m2).1
World Health Organization (WHO)
"Obesity is a chronic disease, prevalent in both developed and developing countries, and affecting children as well as adults"1
The Obesity Society (TOS)
It is the official position of The Obesity Society that obesity should be declared a disease.5
American Medical Association (AMA)
"Recognizing obesity as a disease will help change the way medical community tackles this complex issue that affects approximately one in three Americans"3
American Association of Clinical Endocrinologists (AACE)
"...obesity is a primary disease, and the full force of our medical knowledge should be brought to bear on the prevention and treatment of obesity as a primary disease entitity"4
World Obesity Federation (WOF)
"Obesity is a chronic, relapsing and progressive disease process"2
There is a need for immediate action to prevent and control the obesity epidemic.2 By recognising obesity as a disease, greater action can be taken to prevent its various comorbidities and to combat the harmful stigma surrounding it.2
It's time to treat obesity seriously and provide sufficient time for efforts at prevention, and treatment, to work.2
Obesity is now so common that it is replacing traditional public health concerns, including undernutrition and infectious disease, as one of the most significant contributors to ill health.1 Effective prevention and management of obesity will require an integrated approach, involving actions in all sectors of society.1
With increased medical spending, obesity has become an economic burden on both public and private payers8
People with obesity have higher health care costs than those with normal weight in the United States†,8
†Health care costs associated with obesity are mostly due to treating obesity-related comorbidities.
Adapted from Finkelstein EA, Trogdon JG, Cohen JW, et al. Annual medical spending attributable to obesity: payer- and service-specific estimates. Health Aff (Millwood). 2009;28(5):w822–w831.
The global prevalence of obesity has more than doubled since 19809
In 2014, more than 1.9 billion adults aged ≥18 were overweight. Of these, 32% were obese9
"….obesity…threatens to reduce [a person’s] health in the future even if no health impairment is observed…in the present"5
Research shows a decreased life expectancy of up to 10 years15
Increased BMI is associated with decreased life expectancy15
For every 5 kg/m2 BMI increment above the range of 22.5–25.0 kg/m2, there is a 30% increase in overall mortality‡15
Adapted from Prospective Studies Collaboration. Body-mass index and cause-specific mortality in 900,000 adults: collaborative analyses of 57 prospective studies. Lancet. 2009;373(9669):1083–1096.
‡Data from male subjects.
Weight loss in people with obesity causes changes in appetite hormones that increase hunger and the desire to eat for at least 1 year16
Multiple hormones, such as ghrelin, glucagon-like peptide-1 (GLP-1) and leptin, play an important role in regulating appetite21
The brain has a central role in regulating appetite and energy expenditure21
A review of 14 long-term studies showed that people with obesity regained weight after weight loss achieved by dieting22
"...the high rate of relapse among obese people who have lost weight has a strong physiological basis and is not simply the result of the voluntary resumption of old habits"16
Study participants' weight and diet statuses were assessed at baseline; their weight was then measured at follow-ups for up to 7 years after the diet ended. These data are from a review of 14 diet studies with long-term follow-ups.22
Adapted from Mann T, Tomiyama AJ, Westling E, Lew AM, Samuels B, Chatman J. Medicare's search for effective obesity treatments: diets are not the answer. Am Psychol. 2007;622(3):220–233.
The higher the BMI, the greater the risk of impaired physical functioning, which may include limitations in mobility activities such as walking and dressing24,25
Obesity has a negative impact on physical functioning compared with normal weight (BMI 18.5 to <25.0 kg/m2)24
†SF-36=international health-related quality of life survey.
Adapted from Hopman WM, Berger C, Joseph L, et al. The association between body mass index and health-related quality of life: data from CaMos, a stratified population study. Qual Life Res. 2007;16(10):1595–1603.
BP=blood pressure; CV=cardiovascular; DBP=diastolic blood pressure; HbA1c=glycated haemoglobin; HDL=high density lipoprotein; SBP=systolic blood pressure
Around 7% of weight loss has shown to reduce the incidence of type 2 diabetes by 58%26
Every 1 kg of weight loss can increase HDL levels by 0.0009 mmol/L28
Achieving ≥5% weight loss can lead to 80% risk reduction of sleep apnoea progression29
Clinical practice guidelines for comprehensive medical care of patients with obesity according to disease stage34
AACE=American Association of Clinical Endocrinologists; ACE=American College of Endocrinology; BMI=body mass index; CV=cardiovascular; OSA=obstructive sleep apnoea; T2D=type 2 diabetes; WC=waist circumference; WL=weight loss.
Healthy lifestyle: healthy meal plan and physical activity; Lifestyle therapy: reduced calorie healthy meal plan, physical activity and behavioural interventions.
†Evaluate for presence or absence of adiposity-related complications and severity of complications, e.g. metabolic syndrome, T2D, dyslipidaemia, hypertension, CV disease, OSA, asthma, depression and determine stages to each obesity-related complication; stage 0=no complication; stage 1=mild to moderate; stage 2=severe. ‡Consider if lifestyle therapy fails to prevent progressive weight gain (BMI ≥27.0 kg/m2). §Consider if lifestyle therapy fails to reach target, or introduce concurrently (BMI ≥27.0 kg/m2). ¥Initiate concurrently with lifestyle therapy (BMI ≥27.0 kg/m2).