causes of overweight and obesity

The key causes of the obesity epidemic are massive shifts in environment and lifestyle worldwide. The balance between calorie intake (food and drinks) and energy expenditure (metabolism and physical activity) has shifted as societies mechanise and urbanise. Although the basis of obesity is not only fully understood, the condition has been recognized as a chronic disease caused by a complex set of factors.

Genes

Obesity tends to run in families. If one or both parents are obese a person is more likely to develop obesity. Recent studies acknowledge a condition known as metabolic syndrome that has the potential for defining a cause of obesity.

Eating habits

Overeating leads to weight gain, especially fatty foods (Hot dogs, Big Macs, French fries, macaroni and cheese, nachos, potato chips, ice cream).
Frequency of eating is also important. There are many reports of overweight people eating less often than people with normal weight.

Physical inactivity

Technology has created many time and labour saving products. Some examples include cars, elevators, computers, dishwashers, and televisions. Cars are used to run short distance errands instead of people walking or riding a bicycle. As a result, these recent lifestyle changes have reduced the overall amount of energy expended in our daily lives. Physical activity plays a key role in energy balance.

Slow metabolism

Metabolic rate is the rate at which your body uses food. If your metabolism tends to be slow, you are more likely to store excess calories in the form of fat. Muscle burns more calories than fat, even at rest. So reducing fat and building muscle through weight-bearing exercise can help you burn calories more efficiently.

Psychological factors

Many people eat excessively in response to emotions such as boredom, sadness, stress or anger. Over time, the association between an emotion and food can become firmly fixed. Depression and stress are leading causes of obesity and eating disorders.

Diseases

A condition known as hypothyroidism can lead to weight gain. In fact, hypothyroidism, a condition of the thyroid that slows the body's metabolism way down, is one of the significant causes of obesity in adults and in children. Neurological damage can also interfere with proper calorie intake, especially if the hypothalamus, which regulates appetite, is damaged. In Cushings Syndrome, increased levels of cortisol are secreted. Cortisol, also known as the stress hormone, is known to increase the appetite, which may be a cause of obesity.

Medications

Medications associated with weight gain include certain antidepressants, anti-convulsants, diabetes medications, certain hormones such as oral contraceptives and most corticosteroids. Weight gain may also be seen with some high blood pressure medications and antihistamines.