Overweight

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Overweight
Body mass index chart.svg
The overweight range according to the body mass index (BMI) is the area on the chart where BMI > 25.
Specialty Endocrinology

Being overweight [a] is having more body fat than is optimally healthy. Being overweight is especially common where food supplies are plentiful and lifestyles are sedentary.

Contents

As of 2003, excess weight reached epidemic proportions globally, with more than 1 billion adults being either overweight or obese. [1] In 2013, this increased to more than 2 billion. [2] Increases have been observed across all age groups.

A healthy body requires a minimum amount of fat for proper functioning of the hormonal, reproductive, and immune systems, as thermal insulation, as shock absorption for sensitive areas, and as energy for future use; however, the accumulation of too much storage fat can impair movement, flexibility, and alter the appearance of the body. Some people are naturally heavier and the body positivity movement has worked to reduce body shaming and improve self-confidence amongst heavierset people.

At a basic and fundamental level, the treatments called for are diet and exercise. More extensive treatment may involve support groups like Overeaters Anonymous and mental health treatment. The degree to which treatment is necessary varies culturally and with a medical assessment of an unhealthy weight, treatment has been facilitated by new effective weightloss drugs like Zepbound.

Classification

Category [3] BMI (kg/m2)
Underweight< 18.5
Normal weight18.5–24.9
Overweight25.0–29.9
Obese≥ 30.0

The degree to which a person is overweight is generally described by the body mass index (BMI). Overweight is defined as a BMI of 25 or more, thus it includes pre-obesity defined as a BMI between 25 and 29.9 and obesity as defined by a BMI of 30 or more. [4] [5] Pre-obese and overweight however are often used interchangeably, thus giving overweight a common definition of a BMI of between 25 and 29.9. There are, however, several other common ways to measure the amount of adiposity or fat present in an individual's body.

The body mass index (BMI) is a measure of a person's weight taking into account their height. It is given by the following formula: BMI equals a person's weight (mass) in kilograms divided by the square of the person's height in meters. The units therefore are kg/m2 but BMI measures are typically used and written without units.
BMI provides a significantly more accurate representation of body fat content than simply measuring a person's weight. It is only moderately correlated with both body fat percentage and body fat mass (R2 of 0.68). [6] It does not take into account certain factors such as pregnancy or bodybuilding; however, the BMI is an accurate reflection of fat percentage in the majority of the adult population.
The body volume index (BVI) was devised in 2000 as a computer, rather than manual, measurement of the human body for obesity and an alternative to the BMI
BVI uses 3D software to create an accurate image of a person so BVI can differentiate between people with the same BMI rating, but who have a different shape and different weight distribution.
BVI measures where a person's weight and the fat are located on the body, rather than total weight or total fat content and places emphasis on the weight carried around the abdomen, commonly known as central obesity. There has been an acceptance in recent years that abdominal fat and weight around the abdomen constitute a greater health risk. [7]
A person's weight is measured and compared to an estimated ideal weight. This is the easiest and most common method, but by far the least accurate, as it only measures one quantity (weight) and often does not take into account many factors such as height, body type, and relative amount of muscle mass.
The skin at several specific points on the body is pinched and the thickness of the resulting fold is measured. This measures the thickness of the layers of fat located under the skin, from which a general measurement of total amount of fat in the body is calculated. This method can be reasonably accurate for many people, but it assumes particular fat distribution patterns over the body—which may not apply to all individuals, and does not account for fat deposits not directly under the skin. Also, as the measurement and analysis generally involves a high degree of practice and interpretation, an accurate result requires that a professional perform it. It cannot generally be done by patients themselves.
A small electric current is passed through the body to measure its electrical resistance. As fat and muscle conduct electricity differently, this method can provide a direct measurement of the body fat percentage, in relation to muscle mass. In the past, this technique could only be performed reliably by trained professionals with specialized equipment, but it is now possible to buy home testing kits that let people do this themselves with a minimum of training. Despite the improved simplicity of this process over the years, however, a number of factors can affect the results, including hydration and body temperature, so it still needs some care when taking the test to ensure that the results are accurate.
Considered one of the more accurate methods of measuring body fat, this technique involves complete submersion of a person in water, with special equipment to measure the person's weight while submerged. This weight is then compared with "dry weight" as recorded outside the water to determine overall body density. As fat is less dense than muscle, careful application of this technique can provide a reasonably close estimate of fat content in the body. This technique does, however, require expensive specialized equipment and trained professionals to administer it properly.
Originally developed to measure bone density, DEXA imaging is also used to precisely determine body fat content by using the density of various body tissues to identify which portions of the body are fat. This test is generally considered very accurate, but requires a great deal of expensive medical equipment and trained professionals to perform.

The most common method for discussing this subject and the one used primarily by researchers and advisory institutions is BMI. Definitions of what is considered overweight vary by ethnicity. The current definition proposed by the US National Institutes of Health (NIH) and the World Health Organization (WHO) designates whites, Hispanics and blacks with a BMI of 25 or more as overweight. For Asians, overweight is a BMI between 23 and 29.9 and obesity for all groups is a BMI of 30 or more.

BMI, however, does not account extremes of muscle mass, some rare genetic factors, the very young, and a few other individual variations. Thus it is possible for an individual with a BMI of less than 25 to have excess body fat, while others may have a BMI that is significantly higher without falling into this category. [8] Some of the above methods for determining body fat are more accurate than BMI but are less convenient to measure.

If an individual is overweight and has excess body fat it can create or lead to health risks. Reports are surfacing, however, that being mildly overweight to slightly obese – BMI being between 24 and 31.9 – may be actually beneficial and that people with a BMI between 24 and 31.9 could actually live longer than normal weight or underweight persons. [9] [10]

Health effects

While some negative health outcomes associated with obesity are accepted within the medical community, the health implications of the overweight category are more controversial.

A 2016 review estimated that the risk of death increases by seven percent among overweight people with a BMI of 25 to 27.5 and 20 percent among overweight people with a BMI of 27.5 to 30. [11] Katherine Flegal et al., however, found that the mortality rate for individuals who are classified as overweight (BMI 25 to 29.9) may actually be lower than for those with an "ideal" weight (BMI 18.5 to 24.9), noting that many studies show that the lowest mortality rate is at a BMI close to 25. [12] [13] The specific conclusions appear to depend on what other factors are controlled for, [11] and Flegal has accordingly alleged that the findings from the 2016 review are driven by bias toward preconceived opinions. [14]

Being overweight directly increases the risk of type-II diabetes. [15] Being overweight has been identified as a risk factor for cancer, and Walter Willett predicts that being overweight will overtake smoking as the primary cause of cancer in developed countries as cases of smoking-related cancer dwindle. [16] Being overweight also increases the risk of oligospermia and azoospermia in men. [17]

Psychological well-being is also at risk in the overweight individual due to social discrimination.

Being overweight has been shown not to increase mortality[ qualify evidence ] in older people: in a study of 70 to 75-year old Australians, mortality was lowest for "overweight" individuals (BMI 25 to 29.9), [18] while a study of Koreans found that, among those initially aged 65 or more, an increase in BMI to above 25 was not associated with increased risk of death. [19]

Causes

Belly of overweight teenage male Overweight teenage boy (side).jpg
Belly of overweight teenage male

Being overweight is generally caused by the intake of more calories (by eating) than are expended by the body (by exercise and everyday activity). Factors that may contribute to this imbalance include:

People who have insulin dependent diabetes and chronically overdose insulin may gain weight, while people who already are overweight may develop insulin tolerance, and in the long run develop type II diabetes.

Treatment

The usual treatments for overweight individuals is diet and physical exercise.

Dietitians generally recommend eating several balanced meals dispersed through the day, with a combination of progressive, primarily aerobic, physical exercise. In fact, some research found benefits from physical activity, diet and behaviour changes on BMI in children from 12 to 17 years old. [20]

Considering that most of the treatment strategies are directed to change lifestyle-related behaviours of individuals (namely in dietary and physical activity), the transtheoretical model (TTM) has been used as a framework to design weight management interventions. A systematic review assessed the effectiveness of dietary and physical activity interventions based on the TTM in producing sustainable (one year or longer) weight loss in overweight and obese adults. The included studies did not allow to produce conclusive evidence about the impact of the use of this model combined with these interventions on sustainable weight loss. Nevertheless, very low quality scientific evidence suggests that this approach may lead to improvements in physical activity and dietary habits, namely increased in both exercise duration and frequency, and fruits and vegetables consumption, along with reduced dietary fat intake. [21]

Epidemiology

The World Health Organization (WHO) estimated that nearly 2 billion adults worldwide, aged 18 years and older, were overweight in 2016. [22]

According to the National Health and Nutrition Examination Survey (NHANES), an estimated 71.6% of the United States' adult population aged 20 and over is considered either overweight or obese, and this percentage has increased over the last four decades. [23]

Notes

  1. ↑ The degree to which "fat" is pejorative in colloquial usage must be assessed.

See also

Related Research Articles

<span class="mw-page-title-main">Body mass index</span> Relative weight based on mass and height

Body mass index (BMI) is a value derived from the mass (weight) and height of a person. The BMI is defined as the body mass divided by the square of the body height, and is expressed in units of kg/m2, resulting from mass in kilograms (kg) and height in metres (m).

<span class="mw-page-title-main">Abdominal obesity</span> Excess fat around the stomach and abdomen

Abdominal obesity, also known as central obesity and truncal obesity, is the human condition of an excessive concentration of visceral fat around the stomach and abdomen to such an extent that it is likely to harm its bearer's health. Abdominal obesity has been strongly linked to cardiovascular disease, Alzheimer's disease, and other metabolic and vascular diseases.

<span class="mw-page-title-main">Obesity</span> Medical condition of excess body fat

Obesity is a medical condition, sometimes considered a disease, in which excess body fat has accumulated to such an extent that it can potentially have negative effects on health. People are classified as obese when their body mass index (BMI)—a person's weight divided by the square of the person's height—is over 30 kg/m2; the range 25–30 kg/m2 is defined as overweight. Some East Asian countries use lower values to calculate obesity. Obesity is a major cause of disability and is correlated with various diseases and conditions, particularly cardiovascular diseases, type 2 diabetes, obstructive sleep apnea, certain types of cancer, and osteoarthritis.

Bariatrics is a discipline that deals with the causes, prevention, and treatment of obesity, encompassing both obesity medicine and bariatric surgery.

<span class="mw-page-title-main">Underweight</span> Below a weight considered healthy

An underweight person is a person whose body weight is considered too low to be healthy. A person who is underweight is malnourished.

<span class="mw-page-title-main">Waist–hip ratio</span> Waist measurement divided by hip measurement

The waist–hip ratio or waist-to-hip ratio (WHR) is the dimensionless ratio of the circumference of the waist to that of the hips. This is calculated as waist measurement divided by hip measurement. For example, a person with a 75 cm waist and 95 cm hips has WHR of about 0.79.

<span class="mw-page-title-main">Childhood obesity</span> Obesity in children

Childhood obesity is a condition where excess body fat negatively affects a child's health or well-being. As methods to determine body fat directly are difficult, the diagnosis of obesity is often based on BMI. Due to the rising prevalence of obesity in children and its many adverse health effects it is being recognized as a serious public health concern. The term overweight rather than obese is often used when discussing childhood obesity, as it is less stigmatizing, although the term overweight can also refer to a different BMI category. The prevalence of childhood obesity is known to differ by sex and gender.

The obesity paradox is the finding in some studies of a lower mortality rate for overweight or obese people within certain subpopulations. The paradox has been observed in people with cardiovascular disease and cancer. Explanations for the paradox range from excess weight being protective to the statistical association being caused by methodological flaws such as confounding, detection bias, reverse causality, or selection bias.

<span class="mw-page-title-main">Obesity in the United States</span>

Obesity is common in the United States and is a major health issue associated with numerous diseases, specifically an increased risk of certain types of cancer, coronary artery disease, type 2 diabetes, stroke, and cardiovascular disease, as well as significant increases in early mortality and economic costs.

<span class="mw-page-title-main">Sarcopenic obesity</span> Medical condition: obesity and loss of muscle

Sarcopenic obesity is a combination of two disease states, sarcopenia and obesity. Sarcopenia is the muscle mass/strength/physical function loss associated with increased age, and obesity is based off a weight to height ratio or body mass index (BMI) that is characterized by high body fat or being overweight.

<span class="mw-page-title-main">Preventable causes of death</span> Causes of death that could have been avoided

Preventable causes of death are causes of death related to risk factors which could have been avoided. The World Health Organization has traditionally classified death according to the primary type of disease or injury. However, causes of death may also be classified in terms of preventable risk factors—such as smoking, unhealthy diet, sexual behavior, and reckless driving—which contribute to a number of different diseases. Such risk factors are usually not recorded directly on death certificates, although they are acknowledged in medical reports.

<span class="mw-page-title-main">Obesity-associated morbidity</span> Medical condition

Obesity is a risk factor for many chronic physical and mental illnesses.

<span class="mw-page-title-main">Classification of obesity</span> Overview of the classification of the condition of obesity

Obesity classification is a ranking of obesity, the medical condition in which excess body fat has accumulated to the extent that it has an adverse effect on health. The World Health Organization (WHO) classifies obesity by body mass index (BMI). BMI is further evaluated in terms of fat distribution via the waist–hip ratio and total cardiovascular risk factors. In children, a healthy weight varies with sex and age, and obesity determination is in relation to a historical normal group.

<span class="mw-page-title-main">Weight management</span> Techniques for maintaining body weight

Weight management refers to behaviors, techniques, and physiological processes that contribute to a person's ability to attain and maintain a healthy weight. Most weight management techniques encompass long-term lifestyle strategies that promote healthy eating and daily physical activity. Moreover, weight management involves developing meaningful ways to track weight over time and to identify the ideal body weights for different individuals.

<span class="mw-page-title-main">Obesity in the Middle East and North Africa</span>

Obesity in the Middle East and North Africa is a notable health issue. Out of the 15 fattest nations in the world as of 2014, according to the World Health Organization (WHO), five were located in the Middle East and North Africa region.

Management of obesity can include lifestyle changes, medications, or surgery. Although many studies have sought effective interventions, there is currently no evidence-based, well-defined, and efficient intervention to prevent obesity.

Social stigma of obesity is bias or discriminatory behaviors targeted at overweight and obese individuals because of their weight and high body fat percentage. Such social stigmas can span one's entire life as long as excess weight is present, starting from a young age and lasting into adulthood. Studies also indicate overweight and obese individuals experience higher levels of stigma compared to other people. Stigmatization of obesity is usually associated with increased health risks (morbidity) of being overweight or obese and the possibility of a shorter lifespan (mortality).

The waist-to-height ratio is the waist circumference divided by body height, both measured in the same units.

Normal weight obesity is the condition of having normal body weight, but with a high body fat percentage, leading to some of the same health risks as obesity.

<span class="mw-page-title-main">Body roundness index</span> Body scale based on waist circumference and height

Body roundness index (BRI) is a calculated geometric index used to quantify an aspect of a person's individual body shape. Based on the principle of body eccentricity, it provides a rapid visual and anthropometric tool for health evaluation.

References

  1. ↑ "Obesity and overweight". World Health Organization. 2003. Archived from the original on 2011-12-10. Retrieved 2009-04-27.
  2. ↑ Ng, M.; Fleming, T.; Robinson, M.; Thomson, B.; Graetz, N.; Margono, C.; et al. (29 May 2014). "Global, regional, and national prevalence of overweight and obesity in children and adults during 1980–2013: A systematic analysis for the Global Burden of Disease Study 2013". The Lancet . 384 (9945): 766–781. doi:10.1016/S0140-6736(14)60460-8. ISSN   0140-6736. PMC   4624264 . PMID   24880830.
  3. ↑ The SuRF Report 2 (PDF). The Surveillance of Risk Factors Report Series (SuRF). World Health Organization. 2005. p. 22.
  4. ↑ "Obesity: preventing and managing the global epidemic. Report of a WHO convention". World Health Organization Technical Report Series. 894. Geneva: i–xii, 1–253. 1999. PMID   11234459.
  5. ↑ "Clinical Guidelines on the Identification, Evaluation, and Treatment of Overweight and Obesity in Adults: The Evidence Report" (PDF). National Institutes of Health. September 1998. Retrieved 2009-04-27.
  6. ↑ Gray, D. S.; Fujioka, K. J. (1991). "Use of relative weight and Body Mass Index for the determination of adiposity". Journal of Clinical Epidemiology . 44 (6): 545–50. doi:10.1016/0895-4356(91)90218-X. PMID   2037859.
  7. ↑ Craver, R. (10 September 2008). "Location, not volume, of fat found to be key". Journalnow.com. Archived from the original on 15 May 2013. Retrieved 2008-10-09.
  8. ↑ Gallagher, Dympna; Heymsfield, S. B.; Heo, M.; Jebb, S. A.; Murgatroyd, Y.; Sakamoto, Y. (1 September 2000). "Healthy percentage body fat ranges: an approach for developing guidelines based on body mass index". The American Journal of Clinical Nutrition . 72 (3): 694–701. doi: 10.1093/ajcn/72.3.694 . PMID   10966886.
  9. ↑ Landhuis, Esther. "Healthiest weight just might be 'overweight'". Sciencenews. Retrieved May 11, 2016.
  10. ↑ "Are There Health Benefits to Being Overweight?". wsj.com. WSJ. April 10, 2016. Retrieved October 24, 2017.
  11. 1 2 Di Angelantonio, Emanuele; Bhupathiraju, Shilpa N.; Wormser, David; Gao, Pei; Kaptoge, Stephen; De Gonzalez, Amy Berrington; Cairns, Benjamin J.; Huxley, Rachel; Jackson, Chandra L.; Joshy, Grace; Lewington, Sarah; Manson, Joann E.; Murphy, Neil; Patel, Alpa V.; Samet, Jonathan M.; Woodward, Mark; Zheng, Wei; Zhou, Maigen; Bansal, Narinder; Barricarte, Aurelio; Carter, Brian; Cerhan, James R.; Collins, Rory; Smith, George Davey; Fang, Xianghua; Franco, Oscar H.; Green, Jane; Halsey, Jim; Hildebrand, Janet S.; et al. (13 July 2016). "Body-mass index and all-cause mortality: individual-participant-data meta-analysis of 239 prospective studies in four continents". Lancet. 388 (10046): 776–86. doi:10.1016/S0140-6736(16)30175-1. PMC   4995441 . PMID   27423262.
  12. ↑ Flegal, K. M.; Graubard, B. I.; Williamson, D. F.; Gail, M. H. (2005). "Excess Deaths Associated With Underweight, Overweight, and Obesity". JAMA . 293 (15): 1861–1867. doi:10.1001/jama.293.15.1861. PMID   15840860. Open Access logo PLoS transparent.svg
  13. ↑ Kolata, Gina (7 November 2007). "Causes of Death Are Linked to a Person's Weight". New York Times . Retrieved 2009-04-27.
  14. ↑ Flegal, Katherine M. (2021). "The obesity wars and the education of a researcher: A personal account". Progress in Cardiovascular Diseases. 67: 75–79. doi:10.1016/j.pcad.2021.06.009. PMID   34139265. S2CID   235470848.
  15. ↑ "Type 2 Diabetes - NIDDK". National Institute of Diabetes and Digestive and Kidney Diseases. Retrieved 2024-12-02.
  16. ↑ Wanjek, Christopher (19 February 2008). "Scientists Agree: Obesity Causes Cancer". LiveScience . Retrieved 2009-04-27.
  17. ↑ Sermondade, N.; Faure, C.; Fezeu, L.; et al. (2012). "BMI in relation to sperm count: An updated systematic review and collaborative meta-analysis". Human Reproduction Update. 19 (3): 221–231. doi:10.1093/humupd/dms050. PMC   3621293 . PMID   23242914.
  18. ↑ Flicker, L.; McCaul, K. A.; Hankey, G. J.; Jamrozik, K.; Brown, W. J.; Byles, J. E.; et al. (February 2010). "Body mass index and survival in men and women aged 70 to 75". J Am Geriatr Soc. 58 (2): 234–41. doi: 10.1111/j.1532-5415.2009.02677.x . PMID   20370857.
  19. ↑ Jee, S. H.; Sull, J. W.; Park, J.; Lee, S. Y.; Ohrr, H.; Guallar, E.; Samet, J. M. (24 August 2006). "Body-mass index and mortality in Korean men and women". N Engl J Med. 355 (8): 779–87. doi: 10.1056/NEJMoa054017 . PMID   16926276.
  20. ↑ Al-Khudairy, Lena; Loveman, Emma; Colquitt, Jill L; Mead, Emma; Johnson, Rebecca E; Fraser, Hannah; Olajide, Joan; Murphy, Marie; Velho, Rochelle Marian; O'Malley, Claire; Azevedo, Liane B (2017-06-22). Cochrane Metabolic and Endocrine Disorders Group (ed.). "Diet, physical activity and behavioural interventions for the treatment of overweight or obese adolescents aged 12 to 17 years". Cochrane Database of Systematic Reviews. 2017 (6): CD012691. doi:10.1002/14651858.CD012691. PMC   6481371 . PMID   28639320.
  21. ↑ Mastellos, Nikolaos; Gunn, Laura H; Felix, Lambert M; Car, Josip; Majeed, Azeem (2014-02-05). Cochrane Metabolic and Endocrine Disorders Group (ed.). "Transtheoretical model stages of change for dietary and physical exercise modification in weight loss management for overweight and obese adults". Cochrane Database of Systematic Reviews. 2014 (2): CD008066. doi:10.1002/14651858.CD008066.pub3. PMC   10088065 . PMID   24500864.
  22. ↑ "Obesity and overweight". World Health Organization. Retrieved 20 November 2020.
  23. ↑ "Obesity and Overweight". Centers for Disease Control and Prevention. Retrieved 20 November 2020.
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