Causes Of Obesity
The root cause of obesity is not restricted to a single cause but many different factors. The leading factors that contribute to obesity are lack of exercise, excessive calorie intake, genetics, emotional stress, and sedentary lifestyle.
Obesity is also caused by energy imbalance (between energy intake and expenditure). This means that there is more food energy coming in than going out. If this continues, the person will gain weight until they are obese or overweight.
Many factors may contribute to obesity such as:
1. Genetic factors
Obesity tends to run in families. A child with a single obese parent has a 3-fold risk to become obese while a child with obese parents has a 10-times higher risk of obesity in future.
Genes can affect appetite and thus, how much food you consume. They also control how quickly the body burns calories at rest and during exercise. Genes also influence fat regulation and places of body fat accumulation, particularly fat in the abdomen and around the waist.
Very rarely, mutations in the following genes can cause obesity:
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The ob gene: This gene controls the production of leptin, a hormone made by fat cells and placenta. Leptin controls weight by signaling the brain to eat less when body fat stores are very high. A mutation in the ob gene prevents leptin production and results in severe obesity in a very small number of children.
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The gene for the melanocortin 4 receptor: Melanocortin 4 receptors are located mainly in the brain and play a key role in the regulation of energy. A mutation in this gene may account for obesity in 1 to 4% of children.
However, it should be noted that families not only share genes but also environment, and separating the two factors is quite difficult. In other words, you could be genetically predisposed to being overweight, but your genes may not get activated if you have the right environment and lifestyle.
2. Aging
Obesity can occur at any age, even in children and teenagers. However, obesity becomes more common with age as the amount of muscle tissue decreases as you age. The result is a higher percentage of body fat and a lower basal metabolic rate (because muscle burns more calories). These changes also reduce the need for calories. So, if you don't consciously control what you eat and become more physically inactive as you age, you are most likely to gain weight.
3. Physical inactivity
A major factor that contributes to obesity is inactivity or lack of physical activity. Technological advances such as elevators, cars, remote controls, and online shopping have reduced the amount of calories burnt. More time is spent doing sedentary activities such as watching television, using the computer, smartphones, and playing video games.
Also, many people have desk jobs where they sit for hours without any breaks. This can lead to obesity in some people because their bodies are not burning enough calories when they are sitting at stretch for hours.
4. Unhealthy diet
Modern day diet has significantly shifted to energy-dense foods, which have a large number of calories in a relatively small amount. Most of these foods contain more processed carbohydrates, and trans fat, and less fiber.
Fats, by nature, are energy dense. Carbohydrates increase blood glucose levels, which in turn stimulate the pancreas to release insulin. Insulin promotes the growth of fat tissue and can cause weight gain.
More food advertisements promote high-fat, high-sugar, junk foods like biscuits, namkeen, candy, fizzy drinks, soda, and packaged foods than healthier options like whole grains, vegetables, and fruits. Advertised products are designed to be cheap, have a long shelf-life and are specifically engineered to be addictive and irresistible. These convenience foods significantly contribute to obesity.
5. Frequency of eating
It has been observed that people who eat small meals four or five times daily, have lower cholesterol levels and lower weight and/or more stable blood sugar levels than people who eat big two or three large meals daily. Hence, large and fewer meals can predispose you to gain weight.
6. Eating disorders
The following eating disorders are associated with obesity:
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Binge eating disorder is characterized by binging i.e.; eating large amounts of food during a short amount of time and usually by feeling guilty or out of control.
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Night-eating syndrome involves not eating enough during the day and consuming a lot of food or calories in the evening. It also involves awakening in the middle of the night to eat.
7. Medical conditions
Certain medical conditions can lead to weight gain and eventually might lead to obesity. These include:
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Cushing syndrome is caused by excessive levels of cortisol in the body. It mostly causes fat to accumulate in the face (called moon face), and behind the neck (called a buffalo hump).
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Polycystic ovary syndrome (PCOS) causes obesity in affected women. Levels of testosterone and other male hormones are increased, which causes fat to accumulate in the waist and abdomen.
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Hypothyroidism makes the body use less of the energy that one eats as food. The extra energy is more likely to be stored in the body as fat leading to obesity.
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Insulin resistance is a condition which acts as a precursor for developing type 2 diabetes and can also predispose to obesity.
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Osteoarthritis causes joint pain that may lead to reduced physical activity and thereby cause obesity.
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Prader-Willi syndrome, a rare condition, present at birth that causes uncontrolled hunger.
8. Certain drugs
Many drugs used to treat certain diseases increase the risk of weight gain. These include:
If this issue concerns you, you should discuss your medications with your doctor rather than discontinuing them, as this could have serious side-effects.
9. Pregnancy and menopause
Gaining weight during pregnancy is normal and necessary. However, some women find this weight difficult to lose after the baby is born. This weight gain may predispose to the development of obesity. Having several children close together may compound the problem.
If a pregnant woman is obese or smokes, weight regulation in the child can be disturbed, leading to weight gain during childhood and later.
Many women tend to gain weight after menopause. This weight gain may result from reduced activity and hormonal changes may cause fat to be redistributed and accumulated around the waist.
10. Gut microbiota
Normally, the gut bacteria or gut flora help in digestion of food among other functions. However, an altered gut microenvironment such as long term use of antibiotics, may increase the risk of obesity. Changes in the number and types of bacteria in the digestive system may change how the body processes food.
11. Exposure to chemicals
Obesogens are chemicals that disrupt normal development and metabolism. Being exposed to obesogens early in life can increase the risk of developing obesity. These include cigarette smoke, bisphenol A, air pollution, flame retardants, phthalates, and polychlorinated biphenyls.
12. Psychological factors
Many people eat excessively in response to emotions such as boredom, sadness, stress, anxiety or anger. Adverse childhood events or a childhood history of verbal, physical, or sexual abuse are also associated with a higher risk of obesity.
13. Lifestyle factors
Sleep deprivation or lack of the right amount of sleep can result in weight gain. Sleeplessness results in hormonal changes that increase appetite and cravings for energy-dense foods.
Cessation of smoking usually results in weight gain. When nicotine is stopped, people tend to eat more food, and their metabolic rate decreases, so that fewer calories are burned. As a result, body weight may increase, sometimes leading to obesity.
14. Socioeconomic factors
Obesity and socioeconomic issues are also related. Lack of money to buy healthy foods or familiarity with healthy ways of cooking can increase the risk of obesity. So does lack of safe places to walk or exercise.