Obesity is a medical condition in which excess body fat has accumulated to the extent that it may have a negative effect on health. It is considered as one of the most serious public health problems of the 21st century.

Obesity is best defined by using the body mass index (BMI).The body mass index is calculated using a person's height and weight. The body mass index equals a person's weight in kilograms divided by their height in metres squared. An adult who has a BMI of 25-29.9 is considered overweight, while a BMI over 30 is considered obese. A BMI of 18.5-24.9 is considered normal weight. For patients with a BMI over 40, life expectancy is reduced significantly.

Obesity is a leading preventable cause of death, with increasing rates in adults and children. It has been increasing rapidly worldwide, and the incidence of obesity rates among children and teenagers increased from less than one percent in 1975 for both gender to about 6 percent for girls and 8 percent for boys. Obesity is more common in women than men.  

More children and teenagers in this country are obese now than before. According to a new study conducted by Imperial College London and WHO, experts fear the country is facing the “dual burden” of both malnutrition and obesity. In Bangladesh, obesity among boys was found to be 3 percent in 2016, compared to 0.03 percent in 1975. Among girls, the rate jumped to 2.3 percent from almost nil a few decades ago. The researchers blamed this on an increase in the consumption of energy dense food, especially highly processed carbohydrates.

 Obesity is most commonly caused by a combination of excessive food intake, lack of physical activity, and genetic susceptibility. A few cases are caused primarily by genes, endocrine disorders, medications, or mental disorder. The balance between calorie intake and energy expenditure determines a person's weight.

Overeating leads to weight gain, especially if the diet is high in fat. Foods high in fat or sugar have high energy density. The role of carbohydrates in weight gain is not clear. Carbohydrates increase blood glucose levels, which in turn stimulate insulin release by the pancreas, and insulin promotes the growth of fat tissue and can cause weight gain. Some scientists believe that simple carbohydrates (sugars, desserts, soft drinks) contribute to weight gain because they are more rapidly absorbed into the bloodstream than complex carbohydrates (rice, grains, vegetables, raw fruits).  

Sedentary people burn fewer calories than people who are active. Physical inactivity was strongly correlated with weight gain in both sexes. A person is more likely to develop obesity if one or both parents are obese. Medications associated with weight gain include certain antidepressants, anticonvulsants, certain hormones such as oral contraceptives, and most corticosteroids such as prednisone. Women tend to gain weight especially during certain events such as pregnancy, menopause, and in some cases, with the use of oral contraceptives.

Obesity increases the likelihood of various diseases and conditions, including type-2 diabetes, high blood pressure, high cholesterol, stroke and congestive heart failure. Obesity has been linked to cancers of the colon, rectum, gallbladder, prostate and uterus. Obesity may also be associated with breast cancer, particularly in postmenopausal women.

Obesity is mostly preventable through a combination of social changes and personal choices. Changes to diet and exercising are the main treatments. Most adults need between 1,200-2,800 calories per day, depending on body size and activity level to meet the body's energy needs.

A safe and effective long-term weight reduction and maintenance diet has to contain balanced, nutritious foods to avoid vitamin deficiencies and other diseases of malnutrition. One should eat more nutritious foods that have low energy density, such as vegetables, fruits, grains, lean meat and fish.

The amount of calories burned depends on the type, duration, and intensity of physical activity and exercise. It also depends on the weight of the person. Regular exercise combined with a diet is an important part of a healthy lifestyle to maintain a healthy weight for the long term. About 20-30 minutes of moderate exercise five to seven days a week, preferably daily is usually recommended.

Despite vigorous campaign in print and electronic media regarding healthy nutritious diet and increased availability and accessibility to health facilities, it is a matter of regret and concern that obesity continues to increase at an alarming rate with all possible adverse health outcomes. The issue needs to be addressed seriously and immediately. n