Being overweight can be a medical condition in which excess body fat has accumulated to the extent and can have a bad effect on your health. To define it you can use the body mass index which is the percentage of body fat and total body fat. A child’s healthy weight varies with age and sex. A BMI greater than 95th percentile would be unhealthy. The data percentiles where based on a study from 1963 to 1994. BMI is calculated by dividing a persons mass by the square of his or her height, typically expressed either in metric or US “customary” units: Where lb is the subject’s weight in pounds and in is the subject’s height in inches.
Some Asian populations develop negative health consequences at a lower BMI than Caucasians, some nations have redefined obesity; the Japanese have defined obesity as any BMI greater than 25 while China uses a BMI of greater than 28. Effects on health. Being overweight can also be associated with various diseases, particularly cardiovascular diseases, diabetes mellitus type 2, obstructive sleep apnea, certain types of cancer, and osteoarthritis. Obesity has been found to reduce life expectancy. The lowest risk is found at a BMI of 25 to 27 and increases in both directions for men. For women the lowest risk is found at a BMI of 21 to 23 and increases in both directions.
Overweight is one of the leading causes of death worldwide that can be prevented. A large-scale American and European study have shown that the mortality risk is lowest with a BMI of 22.5-25 kg/m2 in non-smokers and at 24-27 kg/m2 in current smokers, with the risk increasing with changes in either direction. A BMI above 32 has been associated with a mortality rate among women over a 16-year period to be doubled. In the United States it is estimated to cause between 111,909 to 365,000 deaths a year, with approximately 1 million deaths in the European Union attributed to being overweight. Obesity can increases many physical and mental conditions. These common morbidities are most commonly shown in metabolic syndrome, a combination of medical disorders which includes: diabetes mellitus type 2, high blood pressure, high blood cholesterol, and high triglyceride levels.
Some complications are either directly or indirectly related through mechanisms sharing a common cause such as a poor diet or a non-exercising lifestyle. The link between obesity and specific conditions varies. One is the link with type 2 diabetes. Excess body fat underlies 64% of cases of diabetes in men and 77% of cases in women. Health consequences fall into two broad categories: those attributable to the effects of increased fat mass and those due to the increased number of fat cells. Elevated body fat alters your response to insulin, and can potentially lead to insulin resistance. Increased fat can also create an increase of thrombosis.
Some negative health consequences of obesity are well supported by the available evidence, and in certain subgroups seem to be improved at an increased BMI, a phenomenon known as the obesity survival paradox. The paradox was first found in 1999 in overweight and obese people undergoing hemo-dialysis, also has been found in heart failure and peripheral artery disease (PAD).
With heart failure those with a BMI between 30.0-34.9 had lower mortality than those with a normal weight. This has been attributed to the fact that people often lose weight as they become ill. The same findings have been found in other types of heart disease. People with class I obesity and heart disease do not have an increase of heart problems as people of normal weight who also have heart disease. In people with greater stage of obesity the risk can increase. No increase in mortality is seen in the overweight and obese. One study found that the improved survival could be the more aggressive treatment an overweight person will receive after a cardiac event. Yet another states chronic obstructive pulmonary disease (COPD) in those with PAD that the benefit of obesity no longer exists.
When a combination of excessive caloric intake and a lack of physical activity is thought to explain most cases of obesity. A limited number of cases are due primarily to genetics, medical reasons, or psychiatric illness. Increasing rates of obesity can be due to an easily accessible and palatable diet, increased reliance on cars, and mechanized manufacturing.Ten possible factors are: (1) insufficient sleep, (2) endocrine disruptors, (3) decreased variability in ambient temperature, (4) decreased smoking, because smoking suppresses appetite, (5) medications that can cause weight gain, (6) ethnic and age groups that tend to be heavier, (7) pregnancy at a later age can cause susceptibility to obesity in children, (8) risk factors passed on from generation, (9) and naturally higher BMI. Substantial evidence supporting the influence of these mechanisms on the increased prevalence of obesity is still inconclusive.
The dietary energy supply varies between regions and countries. And has changed over time. The average calories available per person per day has increased all over the world except Eastern Europe. Nutritional guidelines have done little to address overeating and poor dietary choice. Between 1971 to 2000, obesity rates in the United States increased from 14.5% to 30.9%. Most of these extra calories came from an increase in carbohydrate consumption rather than fat consumption. The primary source of these extra carbohydrates are sweetened beverages, which now account for almost 25 percent of daily calories in young adults in America. Consumption of sweetened drinks can be a contributing factor in the rising rates of obesity.
The fast-food meals tripled and calorie intake from these meals quadrupled between 1977 and 1995. Agricultural policy and techniques in the United States and Europe have led to lower food prices. In the United States, subsidization of corn, soy, wheat, and rice through the U.S. farm bill has made the main sources of processed food cheap compared to fruits and vegetables. Under-reporting their food intake as compared to people of normal weight. This is supported both by tests and by direct observation.
Obesity can be the result of genetic and environmental factors. Polymorphisms in various genes that control appetite and metabolism can pre-dispose a person to obesity when sufficient calories are present. The percentage of obesity attributed to genetics varies and is from 6% to 85%. Obesity is a major feature in several syndromes, such as Prader-Willi syndrome, Bardet-Biedl syndrome, Cohen syndrome, and MOMO syndrome. People with early-onset obesity which is an onset before 10 years of age and body mass index over three standard deviations above normal. Studies focused on inheritance patterns rather than specific genes have found that 80% of the offspring of two obese parents ended up obese, and less than 10% of the offspring of two parents who were of normal weight.
Certain ethnic groups may be more prone to obesity in an equivalent environment. An ability at periods of prosperity to store fat would be an advantage when food is readily availability, but would not be with a stable food supplies. The Pima Indians, who emerged from a desert environment, developed some of the highest rates of obesity when exposed to a Western lifestyle.
Physical, mental, and pharmaceutical substances can increase the risk of obesity. Medical illnesses that increase obesity risk include several genetic syndromes are: hypothyroidism, Cushing’s syndrome, growth hormone deficiency, and the eating disorders: binge eating disorder and night eating syndrome. Obesity is not regarded as a psychiatric disorder, and is not listed as a psychiatric illness. Certain medications can cause weight gain and/or changes in your body’s composition; which include insulin, sulfonylureas, thiazolidinediones, atypical anti-psychotics, antidepressants, steroids, certain anti-convulsants, pizotifen, and some forms of hormonal contraception.
The correlation between social class and BMI varies globally. In developed countries women of a higher social class were less likely to be obese. No difference was seen among men of different social classes. Among developed countries the levels of adult obesity, and percentage of teenage children who are overweight, are associated with income inequality. A similarity is seen in the US: more adults, even in higher social classes, are obese in more unequal states. Stress and perceived low social status appear to increase risk of obesity. A woman’s risk can increase by 7% per child, while a man’s risk increases by 4% per child.This could be partly due to the fact that having dependent children decreases physical activity in Western parents.