Overweight and obesity are defined as abnormal or excessive fat accumulation that presents a risk to health. A body mass index (BMI) over 25 is considered overweight and over 30 as obese.
Obesity has grown to epidemic proportions, with over 4 million people dying worldwide each year as a result of obesity.1 India now is the third most obese country in the world following US and China.2
Overall, about 13% of the world’s adult population (11% of men and 15% of women) is obese. The worldwide prevalence of obesity nearly tripled between 1975 and 2016. More than 135 million individuals are affected by obesity in India.
According to an Indian Council of Medical Research (ICMR) study, prevalence rate of obesity varies from 16.9%–36.3% respectively across India. The prevalence of obesity rises from 8% to 38% in rural and 13% to 50% in urban areas.
The prevalence of overweight and obesity among children and adolescents aged 5-19 has risen from just 4% in 1975 to just over 18% in 2016
Diagnostic criteria of obesity
In a simple term if an individual is 20% more than his ideal weight, he is suffering from obesity.
1. Body Mass Index (BMI): BMI is a person’s weight in kilograms divided by the square of height in meters.
BMI is a standardized index used to define obesity and to sub categorize into: underweight, healthy weight, overweight, and obesity
2. Waist Circumference (WC) :Waist circumference is an easiest tool to measure abdominal obesity. Abdominal obesity is associated with increased risk of diabetes, cardiovascular diseases and strokes. Obesity is defined as:
WC>102 cm/ 40.15 inches (men)
WC >88cm/ 34.64 inches (women).
3. Waist Hip Ratio: Waist hip ratio (WHR) is calculated by dividing WC by the
maximum hip circumference.WHR shows a graded and a significant association, stronger than that of BMI, with risk of myocardial infarction
WHR= >0.95 (men)
WHR= >0.80 women
Fat Percentage: Measurement of body fat percentage is a direct indicator of obesity. It can be measured through bioelectrical impedance analysis (BIA) or DEXA scan. Obesity is defines as:
Fat Percentage= >25 % in men
Fat Percentage= >33% in women
Consequences of Obesity
As society moves from times of scarcity to times of plenty and excess, obesity is emerging as the most common cause of death both in the developed as well in the developing world. Obesity is responsible for increasing morbidity affecting almost all systems of the body. Diabetes, Heart disease, Hypertension, stroke, Chronic Kidney Disease, Cancers(e.g. colon, Pancreas, Esophagus and liver)are all among the life threatening consequences of obesity. Non Alcoholic fatty liver disease, osteoarthritis, sleep disorders are the other debilitating conditions associated with obesity. GERD ,Sexual dysfunction and reproductive problems, sleep apnea are some of the other obesity related conditions.
Obesity is associated with poor public perception. Social bias and rejection which in turn leads to poorer performance, anxiety, low self esteem and depression and other psychological changes and even psychiatric issues
Pathogenesis of obesity
The pathogenesis of obesity is complex. It is not a mere derivative of food intake & energy expenditure but seems to be a result of impaired brain signals & hormone imbalance leading to pathological over eating and decreased physical activity.
Over the years, many hypotheses have evolved to explain why some people become fat and others remain lean despite eating similar types and amounts of food, and why it is so difficult for reduced-obese persons to maintain weight loss. No single theory can completely explain all manifestations of obesity or apply consistently to all persons. Some of the pathogenic mechanisms of obesity are listed below:
· Obesogenic environment with increasing affluence, money, food abundance, too many incentives to be sedentary and too little need to be physically active is the major reason responsible for obesity.
Genetics can play important role in how the body converts food into energy and how the body burns calorie during exercise. Single or multiple genes may be involved.
Hormone imbalance: An increase in hunger stimulating hormones like Gherlin and a decrease in hunger satisfying hormones like Leptin have been postulated as a major cause of obesity.
Sleep, Stress, and Circadian Rhythms play a major part in the pathogenesis of obesity. Shortened sleep alters the endocrine regulation of the body leading to increased appetite.
Medications like insulin, steroids, anti-depressant and some form of hormonal contraception can all lead to hormonal imbalance, increase in appetite and weight gain.
Certain medical condition like PCOS, Hypothyroidism, Cushing syndrome can also be responsible for obesity
The gut microbiota have been recently implicated in the pathogenesis of obesity. They promote diet induced obesity by a variety of mechanisms the predominant mechanism being the change in the composition of the short chain fatty acids formed as a result of carbohydrate breakdown.
MANAGEMENT OF OBESITY IN ADULTS
When energy intake exceeds energy expenditure by merely 20 kcal/day (the equivalent of 1 tsp. of sugar) a person would gain approximately 1 kg of fat per year (≈20 kg over 2 decades). Hence even a moderate control of the ingested calories would pay long term dividends in managing obesit
After diagnosis of obesity evaluation of patients during the first clinic visit should be protocol-based and comprehensive.
1. History: A detailed history should include onset and rate of weight gain, family history, dietary history, physical activity, previous attempts at weight loss, current medications and co morbidities.
2. Clinical Examination: Patient should be examined thoroughly for sequlae of obesity like pigmented skin (Acanthosis), double chin, hump on the upper back between the shoulder blades etc.
3. Biochemical Evaluation: HbA1c, lipid profile, thyroid profile, OGTT (Oral Glucose Tolerance Test), HOMA IR (Homeostatic model assessment Insulin Resistance). Are all part of the standard work up for these patients. Biochemical parameters can also help in identifying the secondary cause of obesity like PCOS, hypothyroidism, ovarian disease, cushing’s disease and identifying obesity related co- morbidity.
Patient education is the most important component of obesity management. Before starting weight management program a comprehensive patient education session is mandatory.
Goals of Treatment
Obesity is difficult to treat and most patients find it difficult to sustain the weight loss that they achieve. Hence the goals of treatment should be realistic, achievable and sustainable.
It has been found in multiple studies done for diabetes, NASH and heart disease that a weight reduction of 5-10% carries significant health benefits. Therefore the initial aim for any weight loss programme should be to achieve a weight reduction of 5%.
It is recommended that the weight loss should not occur at more than 1kg per week as rapid weight loss in the elderly or those with co morbidities can itself lead to complications.