What are the underlying causes of obesity?

Overweight and obesity are defined as abnormal or excessive fat accumulation that presents a risk to health. A crude population measure of obesity is the body mass index (BMI), a person’s weight (in kilograms) divided by the square of his or her height (in metres). A person with a BMI equal to or more than 25 is considered overweight. A person with a BMI of 30 or more is generally considered obese.

Overweight and obesity are major risk factors for a number of chronic diseases.

Such as

1. Diabetes
2. Cardiovascular diseases
3. Cancer

Once considered a problem only in high-income countries, overweight and obesity are now dramatically on the rise in low- and middle-income countries, particularly in urban settings.

Aetiology of obesity

There are many reasons why a person is obese. The first reason which comes to mind is consuming more calories and spending less. But obesity is a complex condition, there can be several other reasons why people become obese.

The reason for obesity could be one or a combination of these factors

1. Energy imbalance
2. More calorie intake through diet
3. Less spending of calories (less physical activity)
4. Genetic
5. Psychological
6. Environmental
7. Hormonal disturbances and others

Energy Imbalance

It is simple mathematics. To maintain weight the number of calories coming in through diet should be equal to the number of calories spent. Factors such as metabolism and physical activity help in calories being spent or burning the calories. If the number of calories consumed is more than what is burnt over a period of time, we end up gaining weight. First, it is overweight and when that is not controlled it leads to obesity.

Genetics

There has been an indication that heredity has a role to play in obesity.  There is a genetic tendency to put on weight but it is a complex condition.

Psychological factors

There are situations when things become stressful and people resort to food as their comfort/emotional crutch.  To cope with such situations people overeat high-calorie foods which give them a sense of comfort and well-being.

Environment

Sometimes environmental factors such as no open areas for kids to play or adults to walk or exercise may contribute towards weight gain. There are urban areas where there are school and residential areas without much open space for children to have any kind of physical activity. This contributes towards childhood obesity.

Hormonal disturbances

Sometimes hormonal disturbances may be a cause of obesity but it is not that common. One such condition may be Cushing’s syndrome where there is overactivity of the adrenal gland. It is characterized by central obesity. Hypothyroidism may cause increased adipose tissue but retention of water may account for most of the weight gain. Two neurotransmitters, neuropeptide Y and serotonin are found to be involved in body weight regulation.

Lifestyle and genetics play a very important role in people becoming obese. The underlying causes for obesity are not that simple but are far more complex. They may involve social and cultural aspects. There is a lot of research evidence building up that even the gut microbiota has some influence on obesity.

To summarize genetics, lifestyle and our emotional makeup all contribute towards becoming obese.