Overweight causes
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Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]
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Overview
The term overweight is generally used to indicate that a human has more body fat than is considered useful for the optimal functioning of the body. Being overweight is a fairly common condition for many people, especially those in developed nations where food supplies are plentiful and lifestyles often do not involve a lot of activities that generate caloric expenditure. Recent studies have indicated that as much as 64% of the adult US population is overweight, and this number is increasing.[1] A series of graphics from the CDC also describes the obesity prevalence trends in the U.S. in the past 2 decades: Obesity Epidemic: U.S. Temporal Trends 1985-2004 A healthy body requires a minimum amount of fat for the proper functioning of the hormonal, reproductive, and immune systems, as thermal insulation, as shock absorption for sensitive areas, and as excess energy for future use. But the accumulation of too much storage fat can impair movement and flexibility, and can alter the appearance of the body.
Causes
Being overweight is generally caused by the intake of more calories (by eating) than are expended by the body (by exercise and everyday living). Factors which may contribute to this imbalance include:
- Limited exercise and sedentary lifestyle
- Overeating
- Poor nutrition
- Genetic predisposition
- Hormone imbalances (e.g. hypothyroidism)
- Metabolic disorders, which could be caused by repeated attempts to lose weight by Weight cycling,
- An eating disorder (such as binge eating disorder)
- Alcoholism
- Stress
- Insufficient sleep
- Psychotropic medications
- Smoking cessation and other stimulant withdrawal
The amount of body fat is regulated to some extent subconsciously by the brain (by controlling caloric intake through appetite and food preferences). Although the exact mechanisms by which this occurs are not entirely known, one common theory suggests that each person may possess an inherent "set point" weight which the brain attempts to maintain, and that this set point may vary for each individual depending on a variety of factors including genetic predisposition, environment, and past experience.
This leads to the conclusion that some individuals may be predisposed to naturally maintaining different body weights than others, and thus it may be easier for some people to avoid being overweight, while others may find it much more difficult. It also suggests, however, that an individual's set point may be changeable with appropriate environment and conditioning.
While the health issues associated with obesity are well accepted within the medical community, the health implications of the overweight category are more controversial. The generally accepted view has been that overweight often shares adverse risks with obesity, relative to normal weight. Adams et al. estimated that risk of death increases by 20 to 40 percent among overweight persons.[2]
Flegal et al., however, found that mortality rates for individuals who are classified as overweight (BMI 25 to 30) may actually be lower than for those with an "ideal" weight (BMI 18.5 to 25)[3].
Psychological well-being is also at risk in the overweight individual. Discrimination against fat persons is common socially and legally. This may affect their ability to find a mate or employment. The receipt of overt remarks from childhood into old age also shape the personality of the overweight individual, either making him/her more resolute and obstinate or too willing to please others.
References
- ↑ Katherine M. Flegal, PhD; Margaret D. Carroll, MS; Cynthia L. Ogden, PhD; Clifford L. Johnson, MSPH (2002). "Prevalence and Trends in Obesity Among US Adults, 1999-2000". JAMA. 288 (14): 1723&ndash, 1727. PMID 12365955..
- ↑ Kenneth F. Adams, Ph.D., Arthur Schatzkin, M.D., Tamara B. Harris, M.D., Victor Kipnis, Ph.D., Traci Mouw, M.P.H., Rachel Ballard-Barbash, M.D., Albert Hollenbeck, Ph.D., and Michael F. Leitzmann, M.D. (2006). "Overweight, Obesity, and Mortality in a Large Prospective Cohort of Persons 50 to 71 Years Old". NEJM. 355 (8): 763&ndash, 788.
- ↑ Katherine M. Flegal, PhD; Barry I. Graubard, PhD; David F. Williamson, PhD; Mitchell H. Gail, MD, PhD (2005). "Excess Deaths Associated With Underweight, Overweight, and Obesity". JAMA. 293 (15): 1861&ndash, 1867. PMID 15840860..