Obesity is a condition where a person has accumulated abnormal or excessive body fat that causes negative effects on health. For an individual, obesity is usually the result of an imbalance between calories consumed and calories expanded. An increased consumption of high calorie foods, without an equal increase in physical activity leads to an increase in weight. Decreased levels of physical activity will also result in an energy imbalance and lead to weight gain.
Once it was thought as a problem of high income countries now the problem of overweight and obesity are increasing in low income and middle income countries especially in urban areas. Since 1980 obesity has doubled worldwide. In 2014 more than 1.9 billion adults (18 years and older) and 41 million children under the age of five were overweight. Nearly half of the children under five who were overweight or obese in 2014 lived in Asia.
Overweight and obesity are emerging health problems in India. According to National family health survey India-3 (NFHS-3), thirteen percent of women (15-49 Years) and nine percent of men (15-49 Years) were overweight or obese in 2005-06. Overweight prevalence was higher in urban areas than rural areas and lower in people who are involved in agriculture or manual work.
World Health Organization (WHO) defines overweight and obesity as abnormal or excessive fat accumulation that presents a risk to health. A simple measure commonly used to classify overweight and obesity in adults is body mass index (BMI). BMI is defined as a person's weight in kilograms divided by the square of his height in meters (kg/m2). WHO identifies overweight when BMI is greater than or equal to 25; and obesity when BMI is greater or equal to 30. In Asians, the cut-offs for overweight (≥23.0kg/m2) and obesity (≥25.0kg/m2) are lower than WHO criteria due to risk factors and morbidities.
Overweight and obesity kills more people than underweight and act as a predisposing factor for non-communicable diseases such as cardiovascular diseases (heart attack and stroke), diabetes, musculoskeletal disorders (osteoarthritis), some cancers (including breast, ovarian, prostate, liver, gallbladder, kidney, and colon).
Obesity during childhood also causes breathing difficulties, increased risk of fractures, hypertension, and psychological effects. In later life with high chances of obesity, cardiovascular diseases, diabetes can lead to disability and premature death.
Overweight, obesity and their related non-communicable disease are preventable. By making the choice of healthier food and regular physical activity overweight and obesity can be prevented.
Weight gain usually occurs over time. Most people know when they've gained weight. Some of the signs of overweight or obesity include:
Other symptom may be:
Obesity doesn't occur overnight. It develops gradually over time when there is disturbance in energy balance. Energy balance means that “energy in” through food intake and “energy out” through physical activities. Consuming excess calories from high-fat foods, sugars and doing little or no daily physical activity over the long time will lead to weight gain. The reasons for the imbalance between calorie intake and energy out may vary from individual to individual.
There are two different kinds of distribution of body fat that play a role in determining risk of obesity –related health problems;
Fat collected around the waist (apple-shaped figure) carries more risk for obesity related health problems.
(a) Assessment of obesity
Height and weight are the most simple and commonly used measures. Overweight and obesity can be diagnosed by calculating body mass index (BMI) of an individual. BMI generally correlates with fat accumulation although it can sometimes misclassify total body fat content as seen in athletes who are muscular, have high BMI due to muscle weighing more than fat and will have BMI within the overweight range even though they are not fat. The adult BMI cut-offs are not considered appropriate for children as they are still growing.
BMI is defined as a person's weight in kilograms divided by the square of his height in meters (kg/m2). BMI (Metric Formula) =Weight in Kilograms/Height in meters2 .
WHO defines overweight when BMI is greater than or equal to 25.0kg/m2; and obesity when BMI is greater or equal to 30.0kg/m2. In Asians, the cut-offs for overweight (≥23.0kg/m2) and obesity (≥25.0kg/m2) is lower than WHO criteria due to risk factors and morbidities.
Waist circumference: It is measured at the midpoint between the lower border of the rib cage and the iliac crest. Waist circumference ≥102 cm in men and ≥88cm in females is associated with an increased risk of metabolic complications.
Waist: Hip ratio (WHR): High WHR (>1.0 in men and >0.85 in women) indicates abdominal fat accumulation.
(b) Obese persons should have a full medical assessment including routine evaluation of co-morbidity such as diabetes, hypertension, dyslipidaemia. A cardiovascular examination is needed for those older than 40 years or persons having history of heart disease.
(c) Various laboratory tests may be performed to assess co- morbid conditions-
Parks Text book of Preventive and Social Medicine, 22nd Edition, Page No.369-371
For most people who are overweight or obese, the safest and most effective way to lose weight is setting goals with life style changes such as eating fewer calories and being physically active. If lifestyle changes are not enough then only medicines and weight loss surgery are options. While suffering from any co-morbid condition such as diabetes, high blood pressure, cardiovascular disease, osteoarthritis consult your physician prior to starting life style changes.
Set realistic goals:
(a) Life style changes:
Life style changes include healthy eating habits and physical activity.
(i) Healthy eating habits provide body the sufficient nutrients for maintaining good health, but not so many that it causes weight gain. Healthy diet includes:
Portion size: Cutting back on portion size is a good way to eat fewer calories. Avoid oversized portions. Use a smaller plate, bowl, and glass.
Food weight: Eat foods that are lower in calories and fat for a given amount of food; for example; replacing a full-fat food product that weighs two ounces with a low-fat product that weighs the same. Another helpful practice is to eat foods that contain a lot of water, such as vegetables, fruits, and soups.
Very-low-calorie diet (VLCD): gives less than 800 calories a day. Though these diets can lead to rapid weight loss, but they aren't a safe method for everyone. VLCDs are only recommended when obesity-related complication would need rapid weight loss.
(ii) Physical activity- This is an important part of weight reducing programme. Regular physical exercise is essential to increase energy expenditure. Few important suggestions are-
(iii) Behavioral changes- Changing behaviors or habits related to food and physical activity is important for losing weight such as:
(b)Prescription anti-obesity drugs can be useful adjuncts to diet and exercise for obese adults who have failed to achieve weight loss with diet and exercise. Drugs are only prescribed when BMI is 28 kg/m 2 or more with other weight related conditions or BMI 30 kg/m 2 or more.
(c)Weight loss surgery-also called bariatric surgery, is sometimes used to treat people who are severely obese (for BMI of 35 kg/m 2 with co-morbidity or BMI over 40 kg/m 2). Common weight-loss surgeries include:
(d)Vagal nerve blockade is another treatment for obesity. It involves implanting a device under the skin of the abdomen that sends intermittent electrical pulses to the abdominal vagus nerve, which tells the brain when the stomach feels empty or full. This new technology is used in adults who have not been able to lose weight with a weight-loss programme and who have a BMI of 35 - 45 kg/m 2 with at least one obesity-related condition, such as type 2 diabetes.
Obesity can increase the risk of developing many health conditions -
This is observed that increase in the prevalence of obesity is largely due to the obesogenic environment rather than medical and genetic problems in the individuals. Therefore prevention of overweight and obesity should aim creating environments that encourage behaviuoral changes in terms of diet and physical activity.
These efforts must not only focus on the prevention of obesity in those who have not yet become obese (primary prevention), but also on prevention of further weight gain and promotion of weight loss in those who are already obese before they develop the complications of obesity (secondary prevention).
Breastfeeding has been suggested as a potential protective factor against weight gain in childhood and this is important because overweight children and adolescents are at risk of becoming overweight adults.
At individual level, people can follow:
Eating a healthy diet can help in preventing obesity-
Regular physical activity helps maintain a healthy weight-
People should engage in adequate levels of physical activity (60 minutes a day for children and 150 minutes spread through the week for adults). At least 30 minutes of regular, moderate-intensity physical activity on most days reduces the risk of obesity and co-morbidities.
WHO has recommended that food industry can play a significant role in promoting healthy diets by: