It is a condition characterized by an excessive accumulation of body fat. It has many negative impacts on health. If a person’s bodyweight is 20% higher than it should be, he/she is considered to obese.
Defining obesity
There are many ways in which a person’s health in relation to their weight can be classified, but the most widely used method is body mass index (BMI).
BMI is a measure of whether you’re a healthy weight for your height. You can use the BMI healthy weight calculator to work out your score.
For most adults, a BMI of:
- 18.5 to 24.9 means you’re a healthy weight
- 25 to 29.9 means you’re overweight
- 30 to 39.9 means you’re obese
- 40 or above means you’re severely obese
BMI isn’t used to definitively diagnose obesity because people who are very muscular sometimes have a high BMI without excess fat.
But for most people, BMI is a useful indication of whether they’re a healthy weight, overweight or obese.
A better measure of excess fat is waist circumference, which can be used as an additional measure in people who are overweight (with a BMI of 25 to 29.9) or moderately obese (with a BMI of 30 to 34.9).
Generally, men with a waist circumference of 94cm (37in) or more and women with a waist circumference of 80cm (about 31.5in) or more are more likely to develop obesity-related health problems. (Source: NHS-UK)
Health Issues Related With Obesity
Obesity is a very important health problem because it is the root cause of many diseases and is deleterious for general health. For example, cardiovascular diseases, particularly heart attacks and stroke cause 17 million deaths per year all over the world, as the number one causes of preventable deaths. Smoking and obesity are the most important preventable causes of cardiovascular diseases. In addition, the number of deaths caused by Type 2 diabetes, directly associated with obesity, will increase by 50% over the next decade.
If the mortality rate is considered to be 1 when the body mass index is between 20-25, no significant increase occurs between 25-30, but the rate becomes 1.5 times higher when the body mass exceeds 30, becomes 2 times higher when it is between 35-40, and becomes 2.5 times higher when the body mass exceeds 40. After BMI 30, a significant increase occurs in the risk of co-morbid diseases such as diabetes and hypertension.
- Cardiovascular Problems: Coronary heart disease, congestive heart failure, obstructive vascular diseases, venous stasis in the legs, varicose veins.
- Type 2 Diabetes
- Some types of cancer (uterus, breast, prostate and large intestine cancers)
- Hypertension
- Dyslipidemia (Increased blood cholesterol and triglyceride levels)
- Stroke
- Digestive system problems: Fatty liver, gallbladder stones, gastroesophageal reflux disease
- Respiratory tract diseases: Sleep apnea, hyperventilation syndrome, pulmonary embolism
- Musculoskeletal system problems: Osteoarthritis (deterioration of articular cartilage), immobility, herniated lumbar disc
- Urogenital problems: Menstrual irregularity or amenorrhoea, polycystic ovaries, infertility, urinary incontinence.
- Psychosocial problems: Occupational disability, exposure to social discrimination, depression
Measurement of Obesity
The most practical measurement method intended for the evaluation of obesity is the body mass index (BMI), a value calculated by dividing the body weight by the square meter. If your BMI value is between 20 and 25, it means that your weight is within the ideal limits. If this value ranges from 25 to 30, you can be considered overweight. If the BMI value is over 30, it can be said that you are in the obese group.
Worldwide Obesity
Obesity is an increasing public health problem reaching epidemic proportions in both developed and developing countries. According to the MONICA study, the most comprehensive study conducted on this issue that took 12 years; there were 400 million obese and more than 1.4 billion overweight people in the world in 2008 and these figures reached 700 million and more than 2.3 billion respectively in 2015.
In the United States, where obesity is most commonly seen, nearly one in every three adults becomes obese. Albania, Bosnia and the United Kingdom are the leading European countries in this regard. In these countries, the rate obesity has reached 36%.
According to the data from the World Health Organization, obesity is responsible for 80% of Type 2 diabetes, 35% of ischemic heart diseases and 55% of hypertension in European adults. Every year, more than 1 million adults lose their lives due conditions associated with obesity.
Childhood obesity is at an alarming level, as well. It has been reported that the rate of childhood obesity is 10 times higher than the values in 1970. Spain and Portugal are the countries having the highest childhood obesity rates that has reached 35%.
Again, World Health Organization has reported that 30-80% of adults and 20% of children and adolescents are overweight in Europe; and among them, one in every three is obese.
What are the Causes of Obesity?
Obesity is a multifactorial disease; in other words, it is a disease in which many causes play a role. Among these, overnutrition, malnutrition, and inadequate physical activity are considered to be the most important causes. In addition, genetic, environmental, neurological, sociocultural and psychological factors play a role as well. The increase rates of childhood obesity all over the world suggest that environmental factors are more prominent than genetic factors.
Dietary patterns in early years of life have been found to affect obesity in later ages. According to the World Health Organization study, obesity and chronic disease risk can be lowered in children exclusively breastfed for a period of 6 months, with continued breastfeeding for at least 2 years. To sum up the effective factors in obesity;
1-Excessive Consumption of calories
The caloric intake of these days’ people is higher than that of the previous generations. The factor is not only the easy access to cheap high-calorie foods but also the fact that foods are becoming increasingly more processed foods with higher industrial sugar content. Moreover, this is not a problem suffered only by developed countries, but shows an increase all over the world.
Despite billions of dollars being spent on public awareness studies intended for encouraging people to eat healthily, the great majority of the society continues to eat excessively. The prevalence of obesity has doubled all over the world over the last 10 years. For example, the prevalence of obesity in the United States that was 14% in 1980 reached 31% by 2000.
According to studies, the consumption of calories in the USA that was 1,542 per day for women increased up to 1,877 per day by 2004. And in men, the figure increased from 2,450 to 2,618 in the same period. The most important cause of this increase in caloric intake is the boom of carbohydrate foods and sugar production experienced under compulsion of the industry. The most important factor responsible for the increased caloric intake—especially in young adolescents—is the consumption of sugary drinks and fast-foods. The consumption of fast-foods has tripled over the last three decades.
Other reasons that increase calorie consumption are the facts that the sugar lobbies have influence over food policies; the agricultural policies have paved the way for the consumption of more cheap and poor quality foods especially in developed countries; and foods such as genetically modified corn and corn syrup are cheaper than vegetables and fruit.
Contrary to popular belief, obesity does not appear instantly; instead, it appears as a result of excessive calories accumulating gradually over the years. For example, let’s consider a 40-year-old woman weighing 105 kg, who weighed 60 kg when she was 20 years old. This person gained about 2.5 kg each year. 1 kg fat corresponds to 3,500 calories. Accordingly, 2.5 kg fat corresponds to17,500 calories. Daily average caloric intake is equivalent to 1,800 calories. Yearly average caloric intake is 657,000 calories. So, she gained 2.5 kg each year just due to excessive caloric intake in an amount 2.6% higher than what we can burn a day, i.e. extra 48 calories per day. 48 calories correspond to almost half a slice of bread. This example shows the importance of developing wise nutrition tactics for the prevention of obesity. It also gives clues about the impossibility of treating obesity by only preventing that extra 50 calories. If it was possible, diet and exercise would work in all patients.
As the amount of movement decreased, the amount of caloric intake got minimized. But the problem is not just about caloric intake. Physical activity affects even the functioning of your hormones and the processes needed when the foods you eat are processed. In many studies, the beneficial effects of physical activity on insulin levels have been proven. A study published in the January 2012 issue of the American Journal of Preventive Medicine showed that children who had a television in their bedroom were at a higher risk of being obese and overweight, compared to those who didn’t have a television in their room.
3-Inadequate Sleep: Studies have shown that inadequate sleep doubles the risk of obesity. This risk is for both children and adults. The epidemic of obesity in children and adults is paralleled by the silent epidemic of insomnia. Shortening of sleep durations and decrease in sleep quality lead to hormonal imbalance and increased appetite. When you do not sleep enough, your body secretes Ghrelin, a hormone that stimulates appetite. Inadequate sleep also leads to inadequate production of leptin, a hormone that suppresses appetite.
4-Foods affecting the endocrine system, which also interfere with the fat metabolism: A study conducted at the University of Barcelona showed that fructose (fruit sugar) intake affects lipid energy metabolism and consequently leads to fatty liver and metabolic syndrome. Fructose is basically metabolized in the liver. The liver is the target organ, where sugar consumption causes metabolic affects. The study showed that a condition similar to metabolic syndrome developed in rats fed with fructose-containing foods, which caused higher levels of blood lipids, fatty liver, and eventually led to hypertension, resistance to insulin, diabetes and obesity.
Imbalanced diet and the lack of physical exercise are the key factors responsible for the increase of obesity and other metabolic diseases in modern societies. The new epidemiological studies showed that the consumption of fructose-sweetened beverages have more severe effects on women in particular. Fructose is abundant especially in corn syrup, which is used in the production of almost all industrial beverages.
Researchers from Yale University compared the effects of fructose and glucose on the brain with MRI scans, and asserted that a high-fructose diet may be the underlying cause of the current obesity epidemic.
In an article published in JAMA (Journal of the American Medical Association), it was stated that the region in the brain that regulates appetite became active in people who consumed glucose, but remained inactive when they consumed fructose. If those regions become active, the hormones that produce the feeling of satiety, i.e. the stimulants telling you to stop eating, are released.
5-Certain Medications: According to an article published in Annals of Pharmacotherapy, some commonly prescribed medicines may cause weight gain. This effect of corticosteroid drugs and some antidepressants in particular are known. Since the effects of these drugs vary from person to person, their alternatives should be preferred (if possible) especially in overweight and obese individuals.
6-Perpetuation of Physical Obesity: Losing weight is known to become harder in parallel with the length of the period in which a person is overweight. This information suggests that obesity is a condition that reinforces itself and tries to become a permanent state. According to an article published in the Journal of Clinical Investigation, some findings obtained in animal experiments suggested that obesity is a condition reinforcing itself. These findings show the importance of intervening in childhood obesity as early as possible and ensuring children to be protected from this condition—that may affect whole of their lives—and to be treated as soon as possible.
This study also clarifies why adults have difficulty in losing weight successfully with diet and exercise alone, after reaching a certain degree of obesity. In addition to this study, research published in the journal Nature Communications in 2015 showed that losing weight gets harder in parallel with the increase in fat that we carry in our body. The more increase in fat, the more production of a protein that prevents the body from burning fat.
7-Obesity gene: According to an article written by a team of researchers from University College London, published in the July 2013 issue of the Journal of Clinical Investigation, a faulty gene called FTO seems to be the cause of overeating in one in every 6 people. People who carry the FTO gene variant tend to eat much more high-energy and fatty foods, and are generally obese. Such people also need a longer time to feel satiety.