The body stores fat due to energy imbalance

Energy imbalances can cause overweight and obesity. An energy imbalance means that your energy IN is not equal to your energy OUT. This energy is measured in calories. Energy IN is the amount of calories you get from food and drink. Energy OUT is the amount of calories your body uses for things like breathing, digesting, being physically active and regulating body temperature.

Overweight and obesity develop over time when you take in more calories than you consume, or when the energy IN is more than your energy OUT. This type of energy imbalance causes your body to store fat.

Your body uses certain nutrients such as carbohydrates or sugars, proteins and fats from the foods you eat to:

• create energy for immediate use to enhance daily bodily functions and physical activity.
• store energy for future use by your body. Sugars are stored as glycogen in the liver and muscles. Fats are mainly stored as triglyceride in adipose tissue.

The amount of energy your body gets from the food you eat depends on the type of food you eat, how the food is prepared, and how long it has been since you last eaten.

The body has three types of adipose tissue - white, brown, and beige - that it uses to fuel itself, regulate temperature in response to cold, and store energy for future use. Learn about the role of each fat type in maintaining the body's energy balance.

Medical conditions

Some genetic syndromes and endocrine disorders can cause overweight or obesity.

Genetic syndromes

There are several genetic syndromes related to overweight and obesity, including the following.

• Prader-Willi syndrome
• Bardet-Biedl syndrome
• Alström's syndrome
• Cohen syndrome

The study of these genetic syndromes has helped researchers understand obesity.

Endocrine Disorders

Because the endocrine system produces hormones that help maintain the energy balance in the body, the following endocrine disorders or tumors that affect the endocrine system can cause overweight and obesity.

• Hypothyroidism . People with this condition have low levels of thyroid hormones. These low levels are associated with reduced metabolism and weight gain, even when food intake is reduced. People with hypothyroidism also produce less body heat, have a lower body temperature, and do not efficiently use stored fat for energy.
• Cushing's syndrome. People with this condition have high levels of glucocorticoids, such as cortisol, in the blood. High cortisol levels make the body feel like it is under chronic stress. This gives people more appetite and the body starts to store more fatn. Cushing's syndrome can develop after taking certain medications or because the body naturally produces too much cortisol.
• Tumors . Some tumors, such as faucetoparingioma, can cause severe obesity because the tumors develop near parts of the brain that control hunger.

Medicines

Medicines such as antipsychotics, antidepressants, antiepileptics and anti-hyperglycaemics can cause weight gain and lead to overweight and obesity.

Contact your doctor if you notice weight gain while taking any of these medicines. Ask if there are other forms of the same drug or medications that can treat your medical condition but have less of an effect on your weight . Do not stop taking the medicine without talking to your doctor .

Different parts of your body, such as your stomach, intestines, pancreas, and adipose tissue, use hormones to determine how your brain decides whether you are hungry or full. Some of these hormones are insulin, leptin, glucagon-like peptide (GLP-1), peptide YY and ghrelin.