Obesity facts
What is obesity?
The definition of obesity varies depending on what one reads. In general, overweight and obesity indicate a weight greater than what is considered healthy. Obesity is a chronic condition defined by an excess amount of body fat. A certain amount of body fat is necessary for storing energy, heat insulation, shock absorption, and other functions.
Obesity is best defined by using the body mass index. The body mass index is calculated using a person's height and weight. The body mass index (BMI) equals a person's weight in kilograms (kg) divided by their height in meters (m) squared. Since BMI describes body weight relative to height, it is strongly correlated with total body fat content in adults. An adult who has a BMI of 25-29.9 is considered overweight, and an adult who has a BMI over 30 is considered obese.
How common is obesity?
Obesity has reached epidemic proportions in the United States. Over two-thirds of adults are overweight or obese, and one in three Americans is obese. The prevalence of obesity in children has increased markedly. Obesity has also been increasing rapidly throughout the world, and the incidence of obesity nearly doubled from 1991 to 1998.
What are the health risks associated with obesity?
Obesity is not just a cosmetic consideration; it is a dire dilemma directly harmful to one's health. In the United States, roughly 112,000 deaths per year are directly related to obesity, and most of these deaths are in patients with a BMI over 30. For patients with a BMI over 40, life expectancy is reduced significantly. Obesity also increases the risk of developing a number of chronic diseases, including the following:
What causes obesity?
The balance between calorie intake and energy expenditure determines a person's weight. If a person eats more calories than he or she burns (metabolizes), the person gains weight (the body will store the excess energy as fat). If a person eats fewer calories than he or she metabolizes, he or she will lose weight. Therefore the most common causes of obesity are overeating and physical inactivity. Ultimately, body weight is the result of genetics, metabolism, environment, behavior, and culture.
Learn more about: Tegretol | Equetro | Carbatrol
What are other factors associated with obesity?
How is body fat measured?
BMI is a calculated value and approximates the body's fat percentage. Actually measuring a person's body fat percentage is not easy and is often inaccurate if the methods are not monitored carefully. The following methods require special equipment, trained personnel, can be costly, and some are only available in certain research facilities.
The following two methods are simple and straightforward:
Health clubs and weight-loss centers often use the skin caliper or bioelectric impedance analysis method; however, these can yield inaccurate results if an inexperienced person performs them or they are used on someone with significant obesity.
What about weight-for-height tables?
Measuring a person's body fat percentage can be difficult, so other methods are often relied upon to diagnose obesity. Two widely used methods are weight-for-height tables and body mass index (BMI). While both measurements have their limitations, they are reasonable indicators that someone may have a weight problem. The calculations are easy, and no special equipment is required.
Most people are familiar with weight-for-height tables. Although such tables have existed for a long time, in 1943, the Metropolitan Life Insurance Company introduced their table based on policyholders' data to relate weight to disease and mortality. Doctors and nurses (and many others) have used these tables for decades to determine if someone is overweight. The tables usually have a range of acceptable weights for a person of a given height.
One small problem with using weight-for-height tables is that doctors disagree over which is the best table to use. Several versions are available. Many have different weight ranges, and some tables account for a person's frame size, age and sex, while other tables do not.
A significant limitation of all weight-for-height tables is that they do not distinguish between excess fat and muscle. A very muscular person may be classified as obese, according to the tables, when he or she in fact is not.
What is the body mass index (BMI)?
The body mass index (BMI) is a now the measurement of choice for many physicians and researchers studying obesity.
The BMI uses a mathematical formula that accounts for both a person's weight and height.
The BMI measurement, however, poses some of the same problems as the weight-for-height tables. Not everyone agrees on the cutoff points for "healthy" versus "unhealthy" BMI ranges. BMI also does not provide information on a person's percentage of body fat. However, like the weight-for-height table, BMI is a useful general guideline and is a good estimator of body fat for most adults 19 and 70 years of age. However, it may not be an accurate measurement of body fat for body builders, certain athletes, and pregnant women.
The BMI equals a person's weight in kilograms divided by height in meters squared (BMI = kg/m2). To calculate the BMI using pounds, divide the weight in pounds by the height in inches squared and multiply the result by 703.
It is important to understand what "healthy weight" means. Healthy weight is defined as a body mass index (BMI) equal to or greater than 19 and less than 25 among all people 20 years of age or over. Generally, obesity is defined as a body mass index (BMI) equal to or greater than 30, which approximates 30 pounds of excess weight.
The World Health Organization uses a classification system using the BMI to define overweight and obesity.
The table below has already done the math and metric conversions. To use the table, find the appropriate height in the left-hand column. Move across the row to the given weight. The number at the top of the column is the BMI for that height and weight.
BMI Table Courtesy of the National Institutes of Health
Below is a table identifying the risk of associated disease according to BMI and waist size.
Disease Risk* Relative to Normal Weight and Waist Circumference BMI (kg/m2) Obesity Class Men 102cm (40 in) or less
* Disease risk for type 2 diabetes, hypertension, and CVD.
+ Increased waist circumference can also be a marker for increased risk even in persons of normal weight.
Table Courtesy of the National Institutes of Health
Does it matter where body fat is located? (Is it worse to be an "apple" or a "pear"?)
Concern is directed not only at how much fat a person has but also where that fat is located on the body. The pattern of body fat distribution tends to differ in men and women.
In general, women collect fat in their hips and buttocks, giving their figures a "pear" shape. Men, on the other hand, usually collect fat around the belly, giving them more of an "apple" shape. (This is not a hard and fast rule; some men are pear-shaped and some women become apple-shaped, particularly after menopause.)
Apple-shaped people whose fat is concentrated mostly in the abdomen are more likely to develop many of the health problems associated with obesity. They are at increased health risk because of their fat distribution. While obesity of any kind is a health risk, it is better to be a pear than an apple.
In order to sort the types of fruit, doctors have developed a simple way to determine whether someone is an apple or a pear. The measurement is called waist-to-hip ratio. To find out a person's waist-to-hip ratio
Women with waist-to-hip ratios of more than 0.8 and men with waist-to-hip ratios of more than 1.0 are "apples."
Another rough way of estimating the amount of a person's abdominal fat is by measuring the waist circumference. Men with a waist circumference of 40 inches or greater and women with a waist circumference of 35 inches or greater are considered to have increased health risks related to obesity.
What can be done about obesity?
All too often, obesity prompts a strenuous diet in the hopes of reaching the "ideal body weight." Some amount of weight loss may be accomplished, but the lost weight usually quickly returns. Most people who lose weight regain the weight within five years. It is clear that a more effective, long-lasting treatment for obesity must be found.
We need to learn more about the causes of obesity, and then we need to change the ways we treat it. When obesity is accepted as a chronic disease, it will be treated like other chronic diseases such as diabetes and high blood pressure. The treatment of obesity cannot be a short-term "fix" but has to be an ongoing lifelong process.
Obesity treatment must acknowledge that even modest weight loss can be beneficial. For example, a modest weight loss of 5%-10% of the initial weight, and long-term maintenance of that weight loss can bring significant health gains, including
It is not necessary to achieve an "ideal weight" to derive health benefits from obesity treatment. Instead, the goal of treatment should be to reach and hold to a "healthier weight." The emphasis of treatment should be to commit to the process of lifelong healthy living including eating more wisely and increasing physical activity.
In sum, the goal in dealing with obesity is to achieve and maintain a "healthier weight."
What is the role of physical activity and exercise in obesity?
The National Health and Examination Survey (NHANES I) showed that people who engage in limited recreational activity were more likely to gain weight than more active people. Other studies have shown that people who engage in regular strenuous activity gain less weight than sedentary people.
Physical activity and exercise help burn calories. The amount of calories burned depends on the type, duration, and intensity of the activity. It also depends on the weight of the person. A 200-pound person will burn more calories running 1 mile than a 120-pound person, because the work of carrying those extra 80 pounds must be factored in. But exercise as a treatment for obesity is most effective when combined with a diet and weight-loss program. Exercise alone without dietary changes will have a limited effect on weight because one has to exercise a lot to simply lose 1 pound. However regular exercise is an important part of a healthy lifestyle to maintain a healthy weight for the long term. Another advantage of regular exercise as part of a weight-loss program is a greater loss of body fat versus lean muscle compared to those who diet alone.
Other benefits of exercise includeRemember, these health benefits can occur independently (with or without) achieving weight loss. Before starting an exercise program, you should talk to your doctor about the type and intensity of the exercise program.
General exercise recommendationsThe following people should consult a doctor before vigorous exercise:
What is the role of diet in the treatment of obesity?
The first goal of dieting is to stop further weight gain. The next goal is to establish realistic weight-loss goals. While the ideal weight corresponds to a BMI of 20-25, this is difficult to achieve for many people. Thus, success is higher when a goal is set to lose 10%-15% of baseline weight as opposed to 20%-30% or greater. It is also important to remember that any weight reduction in an obese person would result in health benefits.
One effective way to lose weight is to eat fewer calories. One pound is equal to 3,500 calories. In other words, you have to burn 3,500 more calories than you consume to lose 1 pound. Most adults need between 1,200-2,800 calories per day, depending on body size and activity level to meet the body's energy needs.
If you skip that bowl of ice cream, then you will be one-seventh of the way to losing that pound! Losing 1 pound per week is a safe and reasonable way to take off extra pounds. The higher the initial weight of a person, the more quickly he/she will achieve weight loss. This is because for every 1 kilogram (2.2 pounds) of body weight, approximately 22 calories are required to maintain that weight. So for a woman weighing 100 kilograms (220 pounds), he or she would require about 2,200 calories a day to maintain his or her weight, while a person weighing 60 kilograms (132 pounds) would require only about 1,320 calories. If both ate a calorie-restricted diet of 1,200 calories per day, the heavier person would lose weight faster. Age also is a factor in calorie expenditure. Metabolic rate tends to slow as we age, so the older a person is, the harder it is to lose weight.
There is controversy in regard to carbohydrates and weight loss. When carbohydrates are restricted, people often experience rapid initial weight loss within the first two weeks. This weight loss is due mainly to fluid loss. When carbohydrates are added back to the diet, weight gain often occurs, simply due to a regain of the fluid.
General diet guidelines for achieving and (just as importantly) maintaining a healthy weight.
What is obesity?
The definition of obesity varies depending on what one reads. In general, overweight and obesity indicate a weight greater than what is considered healthy. Obesity is a chronic condition defined by an excess amount of body fat. A certain amount of body fat is necessary for storing energy, heat insulation, shock absorption, and other functions.
Obesity is best defined by using the body mass index. The body mass index is calculated using a person's height and weight. The body mass index (BMI) equals a person's weight in kilograms (kg) divided by their height in meters (m) squared. Since BMI describes body weight relative to height, it is strongly correlated with total body fat content in adults. An adult who has a BMI of 25-29.9 is considered overweight, and an adult who has a BMI over 30 is considered obese.
How common is obesity?
Obesity has reached epidemic proportions in the United States. Over two-thirds of adults are overweight or obese, and one in three Americans is obese. The prevalence of obesity in children has increased markedly. Obesity has also been increasing rapidly throughout the world, and the incidence of obesity nearly doubled from 1991 to 1998.
What are the health risks associated with obesity?
Obesity is not just a cosmetic consideration; it is a dire dilemma directly harmful to one's health. In the United States, roughly 112,000 deaths per year are directly related to obesity, and most of these deaths are in patients with a BMI over 30. For patients with a BMI over 40, life expectancy is reduced significantly. Obesity also increases the risk of developing a number of chronic diseases, including the following:
What causes obesity?
The balance between calorie intake and energy expenditure determines a person's weight. If a person eats more calories than he or she burns (metabolizes), the person gains weight (the body will store the excess energy as fat). If a person eats fewer calories than he or she metabolizes, he or she will lose weight. Therefore the most common causes of obesity are overeating and physical inactivity. Ultimately, body weight is the result of genetics, metabolism, environment, behavior, and culture.
Learn more about: Tegretol | Equetro | Carbatrol
What are other factors associated with obesity?
How is body fat measured?
BMI is a calculated value and approximates the body's fat percentage. Actually measuring a person's body fat percentage is not easy and is often inaccurate if the methods are not monitored carefully. The following methods require special equipment, trained personnel, can be costly, and some are only available in certain research facilities.
The following two methods are simple and straightforward:
Health clubs and weight-loss centers often use the skin caliper or bioelectric impedance analysis method; however, these can yield inaccurate results if an inexperienced person performs them or they are used on someone with significant obesity.
What about weight-for-height tables?
Measuring a person's body fat percentage can be difficult, so other methods are often relied upon to diagnose obesity. Two widely used methods are weight-for-height tables and body mass index (BMI). While both measurements have their limitations, they are reasonable indicators that someone may have a weight problem. The calculations are easy, and no special equipment is required.
Most people are familiar with weight-for-height tables. Although such tables have existed for a long time, in 1943, the Metropolitan Life Insurance Company introduced their table based on policyholders' data to relate weight to disease and mortality. Doctors and nurses (and many others) have used these tables for decades to determine if someone is overweight. The tables usually have a range of acceptable weights for a person of a given height.
One small problem with using weight-for-height tables is that doctors disagree over which is the best table to use. Several versions are available. Many have different weight ranges, and some tables account for a person's frame size, age and sex, while other tables do not.
A significant limitation of all weight-for-height tables is that they do not distinguish between excess fat and muscle. A very muscular person may be classified as obese, according to the tables, when he or she in fact is not.
What is the body mass index (BMI)?
The body mass index (BMI) is a now the measurement of choice for many physicians and researchers studying obesity.
The BMI uses a mathematical formula that accounts for both a person's weight and height.
The BMI measurement, however, poses some of the same problems as the weight-for-height tables. Not everyone agrees on the cutoff points for "healthy" versus "unhealthy" BMI ranges. BMI also does not provide information on a person's percentage of body fat. However, like the weight-for-height table, BMI is a useful general guideline and is a good estimator of body fat for most adults 19 and 70 years of age. However, it may not be an accurate measurement of body fat for body builders, certain athletes, and pregnant women.
The BMI equals a person's weight in kilograms divided by height in meters squared (BMI = kg/m2). To calculate the BMI using pounds, divide the weight in pounds by the height in inches squared and multiply the result by 703.
It is important to understand what "healthy weight" means. Healthy weight is defined as a body mass index (BMI) equal to or greater than 19 and less than 25 among all people 20 years of age or over. Generally, obesity is defined as a body mass index (BMI) equal to or greater than 30, which approximates 30 pounds of excess weight.
The World Health Organization uses a classification system using the BMI to define overweight and obesity.
The table below has already done the math and metric conversions. To use the table, find the appropriate height in the left-hand column. Move across the row to the given weight. The number at the top of the column is the BMI for that height and weight.
BMI Table Courtesy of the National Institutes of Health
Below is a table identifying the risk of associated disease according to BMI and waist size.
Disease Risk* Relative to Normal Weight and Waist Circumference BMI (kg/m2) Obesity Class Men 102cm (40 in) or less
* Disease risk for type 2 diabetes, hypertension, and CVD.
+ Increased waist circumference can also be a marker for increased risk even in persons of normal weight.
Table Courtesy of the National Institutes of Health
Does it matter where body fat is located? (Is it worse to be an "apple" or a "pear"?)
Concern is directed not only at how much fat a person has but also where that fat is located on the body. The pattern of body fat distribution tends to differ in men and women.
In general, women collect fat in their hips and buttocks, giving their figures a "pear" shape. Men, on the other hand, usually collect fat around the belly, giving them more of an "apple" shape. (This is not a hard and fast rule; some men are pear-shaped and some women become apple-shaped, particularly after menopause.)
Apple-shaped people whose fat is concentrated mostly in the abdomen are more likely to develop many of the health problems associated with obesity. They are at increased health risk because of their fat distribution. While obesity of any kind is a health risk, it is better to be a pear than an apple.
In order to sort the types of fruit, doctors have developed a simple way to determine whether someone is an apple or a pear. The measurement is called waist-to-hip ratio. To find out a person's waist-to-hip ratio
Women with waist-to-hip ratios of more than 0.8 and men with waist-to-hip ratios of more than 1.0 are "apples."
Another rough way of estimating the amount of a person's abdominal fat is by measuring the waist circumference. Men with a waist circumference of 40 inches or greater and women with a waist circumference of 35 inches or greater are considered to have increased health risks related to obesity.
What can be done about obesity?
All too often, obesity prompts a strenuous diet in the hopes of reaching the "ideal body weight." Some amount of weight loss may be accomplished, but the lost weight usually quickly returns. Most people who lose weight regain the weight within five years. It is clear that a more effective, long-lasting treatment for obesity must be found.
We need to learn more about the causes of obesity, and then we need to change the ways we treat it. When obesity is accepted as a chronic disease, it will be treated like other chronic diseases such as diabetes and high blood pressure. The treatment of obesity cannot be a short-term "fix" but has to be an ongoing lifelong process.
Obesity treatment must acknowledge that even modest weight loss can be beneficial. For example, a modest weight loss of 5%-10% of the initial weight, and long-term maintenance of that weight loss can bring significant health gains, including
It is not necessary to achieve an "ideal weight" to derive health benefits from obesity treatment. Instead, the goal of treatment should be to reach and hold to a "healthier weight." The emphasis of treatment should be to commit to the process of lifelong healthy living including eating more wisely and increasing physical activity.
In sum, the goal in dealing with obesity is to achieve and maintain a "healthier weight."
What is the role of physical activity and exercise in obesity?
The National Health and Examination Survey (NHANES I) showed that people who engage in limited recreational activity were more likely to gain weight than more active people. Other studies have shown that people who engage in regular strenuous activity gain less weight than sedentary people.
Physical activity and exercise help burn calories. The amount of calories burned depends on the type, duration, and intensity of the activity. It also depends on the weight of the person. A 200-pound person will burn more calories running 1 mile than a 120-pound person, because the work of carrying those extra 80 pounds must be factored in. But exercise as a treatment for obesity is most effective when combined with a diet and weight-loss program. Exercise alone without dietary changes will have a limited effect on weight because one has to exercise a lot to simply lose 1 pound. However regular exercise is an important part of a healthy lifestyle to maintain a healthy weight for the long term. Another advantage of regular exercise as part of a weight-loss program is a greater loss of body fat versus lean muscle compared to those who diet alone.
Other benefits of exercise includeRemember, these health benefits can occur independently (with or without) achieving weight loss. Before starting an exercise program, you should talk to your doctor about the type and intensity of the exercise program.
General exercise recommendationsThe following people should consult a doctor before vigorous exercise:
What is the role of diet in the treatment of obesity?
The first goal of dieting is to stop further weight gain. The next goal is to establish realistic weight-loss goals. While the ideal weight corresponds to a BMI of 20-25, this is difficult to achieve for many people. Thus, success is higher when a goal is set to lose 10%-15% of baseline weight as opposed to 20%-30% or greater. It is also important to remember that any weight reduction in an obese person would result in health benefits.
One effective way to lose weight is to eat fewer calories. One pound is equal to 3,500 calories. In other words, you have to burn 3,500 more calories than you consume to lose 1 pound. Most adults need between 1,200-2,800 calories per day, depending on body size and activity level to meet the body's energy needs.
If you skip that bowl of ice cream, then you will be one-seventh of the way to losing that pound! Losing 1 pound per week is a safe and reasonable way to take off extra pounds. The higher the initial weight of a person, the more quickly he/she will achieve weight loss. This is because for every 1 kilogram (2.2 pounds) of body weight, approximately 22 calories are required to maintain that weight. So for a woman weighing 100 kilograms (220 pounds), he or she would require about 2,200 calories a day to maintain his or her weight, while a person weighing 60 kilograms (132 pounds) would require only about 1,320 calories. If both ate a calorie-restricted diet of 1,200 calories per day, the heavier person would lose weight faster. Age also is a factor in calorie expenditure. Metabolic rate tends to slow as we age, so the older a person is, the harder it is to lose weight.
There is controversy in regard to carbohydrates and weight loss. When carbohydrates are restricted, people often experience rapid initial weight loss within the first two weeks. This weight loss is due mainly to fluid loss. When carbohydrates are added back to the diet, weight gain often occurs, simply due to a regain of the fluid.
General diet guidelines for achieving and (just as importantly) maintaining a healthy weight.
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