Risk Factors and Medical Conditions Leading to Obesity
Being overweight means that too much of a person’s body is made up of stored fat. Anyone can become overweight when the energy they put into their body in the form of food and drink is more than the energy they use up in exercise and daily living. This leftover energy is transformed into fat by the body.
To become obese, it usually takes years for the fat to build up. A person is defined as being medically obese if they are well above the ideal body weight for their height, age, sex and body build to the extent which can seriously affect their health. Doctors use a number of calculations to define obesity, including the body mass index (BMI), waist-to-hip and waist-to-height ratios and the body adiposity index (BAI) as well as several other more sophisticated tools.
Causes of Obesity other than Overeating and Inactivity
In more than 99% of cases, obesity is caused by storing excess energy that a person consumes as fat. However, there are also other reasons why it can be easier to put on weight in the first place. Sometimes there may be a genetic cause for obesity while in exceptional circumstances the weight gain can be made worse by other factors such as certain drugs, hormonal changes or an under-active thyroid gland.
An improved diet and a regular exercise programme are the main treatments for obesity. But for a small percentage of people who are overweight or obese due to some other causes this may not be enough. These other factors can be any of the following:
- Depression: Emotional problems like depression but also stress, anger or anxiety can make a person feel very tired and unenergetic, and more like comfort eating.
- Medications: Not only depression itself, but also certain drugs used to treat it can cause weight gain. Some contraceptive pills and injections can cause weight gain by increasing appetite, but they would usually only account for up to four kilograms at the very most. Other medications that can increase appetite include some types of sulphur-based antibiotics, hormonal drugs and some steroids. In addition, some insulin injections and pills for diabetes can also increase appetite.
- Under-active thyroid gland: This hormonal problem is also known as hypothyroidism. The thyroid glands produce a hormone which regulates the body’s production and use of energy. If they produce too little of the thyroid hormone, less energy is used by the body, increasing a person’s tendency to put on weight. Hypothyroidism normally has an array of other symptoms in addition to weight gain. They include a hoarse voice, a swollen gland in the front of the neck and puffiness around the eyes, as well as other associated complications. The condition is usually treated with medications and most of the symptoms, including weight gain, are reversed in a few weeks.
- Cushing’s syndrome: This is a rare condition except in people who are taking steroid drugs. It occurs when the body has too much of a steroid called cortisol. The cortisol can come from medication that a patient is taking or, in exceptional cases, it can be made by the body itself. Cushing’s syndrome can make a patient put on weight in specific areas and makes one look rather lemon-shaped, often with a very rounded, moon-like face. Symptoms include high blood sugar levels, thin skin, thinning hair, brittle bones, stomach ulcers, bruising, cataracts and elevated blood pressure. Treatments usually involve medication and sometimes surgery, depending on the cause of the excess cortisol.
- Oedema: This is the build-up of fluid in the body which causes swelling. It often occurs in the tissues of the legs and ankles, or in the abdomen or lungs. A patient with oedema puts on weight, but this extra weight is fluid and not fat. Oedema usually develops when the heart stops pumping blood effectively or the kidneys are diseased and fail to get rid of fluid properly. In some cases, liver failure can also make the stomach swell with fluid. More rarely, some cancers, such as abdominal, breast or ovarian cancers have the same effect. The symptoms of the disease (other than swelling) vary according to the underlying cause, but can include pain in the chest, breathlessness and a cough (especially with frothy or blood-stained phlegm). Treatment is specific to the patient, depending on the cause of their oedema.
- Polycystic ovary syndrome (PCOS): It is a common hormonal disorder affecting women of childbearing age. When a woman’s hormones get out of balance they cause problems in the ovaries. Patients with this syndrome usually have enlarged ovaries and irregular menstrual cycles and develop cysts in the ovaries (hence the name of the condition). PCOS can eventually result in infertility. Other symptoms include obesity, difficulty losing weight, acne, excessive facial hair growth, thinning of the scalp hair and depression. PCOS can be managed with healthy diet and exercise while the doctor may prescribe birth control pills to help regulate menstrual cycles and reduce excessive facial hair growth.
- Brain tumours: Very occasionally, brain tumours can induce hormonal changes that are causing weight gain. Sometimes, damage to the brain after trauma or infections can also have this effect. However, these cases are very rare and are usually associated with additional symptoms such as headaches or visual disturbances.
- Genetic or inherited disorders: Some specific genetic disorders can make a person more likely to gain weight and, since they are inherited, the weight gain will usually start in childhood. Genetic disorders commonly associated with obesity include Ayazi syndrome, Bardet-Biedl syndrome, Cohen syndrome, MOMO syndrome and Prader-Willi syndrome.
In addition to medical conditions and drugs, there are certain other risk factors that may be beyond a person’s control which can contribute to undesired weight gain. These include:
- Genes: In some people there can be a genetic cause for obesity. A particular gene that contributes to being overweight can run in some families. This gene may involve abnormalities in the transport of glucose into cells and the way in which the body regulates this process. That is, a person’s genes may eventually determine the amount of fat stored and also where it is stored in the body. Still, more research needs to be undertaken into the genetic causes of obesity. However, obesity in families is more often due to the fact that families tend to eat the same type and the same amount of foods and also do similar amounts of exercise.
- Aging: For most individuals it is normal to put on weight as they get older. This is because people generally do less exercise as they age and thus lose muscle. But, muscle burns calories. So, if people do not adjust their intake of calories to the lower rate at which they burn them, they gain weight. Also, most people put on weight slowly over the years and, therefore, the retired person has had many more years of life in which to accumulate fat.
- Pregnancy: Hormonal changes in the female body during pregnancy induce metabolic changes that lead to a higher accumulation of body fat which is needed for the baby. Although this is inevitable, it is not necessary to keep these extra pounds for too long after giving birth.
- Sleep deprivation: Contrary to a common sense view, a lack of sleep has been shown to increase the risk of weight gain. This is in part due to the fact that people tend to eat more when sleeping less. Sleep deprivation was found to mess up with the hormones leptin and ghrelin that regulate food intake and energy use, boosting the levels of the hunger-stimulating hormone and reducing the levels of the hunger-suppressing hormone.
- Quitting smoking: Nicotine raises the rate at which the body burns calories. People who recently quit smoking have to deal with a slower rate than when they smoked. Also, when no longer smoking, some people tend to overeat out of boredom.
- Alcohol: Contrary to popular belief, most alcoholic drinks are not high in calories. However, alcohol stimulates appetite and overeating makes one fat.