Dieting; Obesity; Weight loss
Where you live plays a role in your risk for obesity. Simply living in the United States makes a person more susceptible to obesity. The prevalence of obesity in America has risen dramatically over the past few years and continues to increase.
Risk by Age. People of any age are at risk for obesity. More children and adolescents are overweight in America than ever before. Gaining some weight is common with age, and adding about 10 pounds to a normal base weight over time is not harmful. The typical weight gain in American adults over 50, however, is worrisome. By age 55, the average American has added nearly 40 pounds of fat during the course of adulthood. This condition is made worse by the fact that muscle and bone mass decrease with age.
Risk by Gender. In men, BMI tends to increase until age 50 and then it levels off. In women, weight tends to increase until age 70 before it plateaus. There are three high-risk periods for weight gain in women:
These findings are significant because they may allow women to target high-risk times, and consequently prevent unnecessary weight gain.
Risk by Economic Group. Obesity is more prevalent in lower economic groups. Low income women and their families tend to have fewer fruits and vegetables and are actually taking in more calories a day than higher-income women. However, obesity is increasing in young adults with college education as well as in other groups.
Ethnic Groups. Among ethnic groups in general, African-American women are more overweight than Caucasian women are, but African-American men are less obese than Caucasian men are. Hispanic men and women tend to weigh more than Caucasians.
US Regions. Regionally, the prevalence of obesity is lowest in the Western states and highest in the South.
A number of dietary habits put people at risk for becoming overweight:
Anyone with Sedentary Lifestyles. Office workers, drivers, and people who sit for long periods are at higher risk for obesity.
Ex-Smokers. The trend toward weight increase has followed the trend for quitting smoking. Nicotine increases the metabolic rate, and quitting, even without eating more, can cause weight gain, which may be considerable. It is important to note that weight control is not a valid reason to smoke. People in previous centuries did not smoke cigarettes, nor were they usually obese.
Shift-Workers. A recent study found that individuals who work late shifts (between 4 p.m. and 8 a.m.) tend to eat more and take longer naps than day workers, and they are more likely to gain excess weight.
People with Disabilities. Obesity rates are higher than average in people with physical or mental disabilities. Those with disabilities in the lower part of the body, such as the legs, are at highest risk.
People with Chronic Mental illnesses. People who have a chronic mental illness are at high risk for obesity and diabetes, most likely due to their lifestyle. In addition, many of the medications used to treat chronic mental illnesses can cause weight gain and increase the risk of diabetes.
Weight gain in children and adolescents is rising at an alarming rate. In 2004, 19% of young children aged 6 - 11 were overweight, an increase of 8% from 1994. Among children aged 2 - 5, 13.9% were overweight in 2004, up from 7.2% 10 years earlier.
Children and adolescents are considered to be overweight if their BMI is above 95% of the children in their age and sex categories. Ethnic variations, timing of growth spurts, and higher normal fat levels around puberty can affect these measurements.
Lifestyle Factors. Without educational or parental guidance, children are extremely vulnerable to the intense cultural pressures that are largely responsible for the obesity epidemic. The following are some specific problems created by the culture:
Neither the media nor the educational system has strong well-financed programs that encourage healthy alternatives, including exercise and healthy foods.
Family History. Parental obesity more than doubles the risk that a young child, whether thin or overweight, will become obese as an adult. In older children and teenagers, obesity in parents starts to count less as a predictor for body weight than their own weight. The risk for obesity may be due to environmental or genetic factors, or both.
Although some small studies have reported protection against obesity from breastfeeding, evidence is weak. Nevertheless, given the healthful effects of breastfeeding and the possibility that it may have even a slight impact on childhood obesity, it is highly recommended.
Biological Effect of Childhood Obesity on Adult Weight
Achieving a healthy weight becomes more difficult as children get older. The odds of obesity persisting into adulthood range from 20% in 4 year olds to 80% in teenagers. One reason for the persistence is biological. The fat cells change in number or mass depending on a person's age:
Bessesen DH. Update on obesity. J Clin Endocrinol Metab. 2008;93(6):2027-2034.
Butryn ML, Phelan S, Hill JO, et al. Consistent self-monitoring of weight: a key component of successful weight loss maintenance. Obesity(Silver Spring). 2007;15(12):3091-3096.
Chu SY, Kim, Lau J, et al. Maternal obesity and risk of stillbirth: a metaanalysis. Am J Obstet Gynecol. 2007;197(3):223-8.
DeMaria EJ. Bariatric surgery for morbid obesity. N Engl J Med. 2007;356(21): 2176-2183.
Despres JP, Golay A, Sjostrom L; Rimonabant in Obesity-Lipids Study Group. Effects of rimonabant on metabolic risk factors in overweight patients with dyslipidemia. N Engl J Med. 2005;353(20):2121-2134.
Dixon JB, O'Brien PE, Playfair J, et al. Adjustable gastric banding and conventional therapy for type 2 diabetes: a randomized controlled trial. JAMA. 299(3):316-323.
Fernstrom JD, Courcoulas AP, Houck PR, et al. Long-term changes in blood pressure in extremely obese patients who have undergone bariatric surgery. Arch Surg. 2006;141(3):276-283.
Gardner CD, Kiazand A, Alhassan S, et al. Comparison of the Atkins, Zone, Ornish, and LEARN diets for change in weight and related risk factors among overweight premenopausal women: the A TO Z Weight Loss Study: a randomized trial. JAMA. 2007;297(9): 969-977.
Gorin AA, Phelan S, Wing RR, et al. Promoting long-term weight control: does dieting consistency matter? Int J Obes Relat Metab Disord. 2004;28(2):278-281.
Haworth CM, Plomin R, Carnell S, et al. Childhood Obesity: Genetic and Environmental Overlap with Normal-range BMI. Obesity (Silver Spring). 2008 Apr 17 [Epub ahead of print].
Hsing AW, Sakoda LC, Chua S Jr. Obesity, metabolic syndrome, and prostate cancer. Am J Clin Nutr. 2007;86(3):s843-857.
Hughes AR, Stewart L, Chapple J, et al. Randomized, controlled trial of a best-practice individualized behavioral program for treatment of childhood overweight: Scottish Childhood Overweight Treatment Trial (SCOTT). Pediatrics. 2008;121(3):e539-546.
Koeppen-Schomerus G, Wardle J, Plomin R. A genetic analysis of weight and overweight in 4-year-old twin pairs. Int J Obes Relat Metab Disord. 2001;25(6):838-44.
Kramer MS, Matush L, Vanilovich I, et al. Effects of prolonged and exclusive breastfeeding on child height, weight, adiposity, and blood pressure at age 6.5 y: evidence from a large randomized trial. Am J Clin Nutr. 2007;86(6):1717-1721.
Leslie D. Bariatric surgery primer for the internist: keys to the surgical consultation. Med Clin North Am. 2007; 91(3):353-381, x.
Mustelin L, Silventoinen K, PietilÃinen K, Rissanen A, Kaprio J. Physical activity reduces the influence of genetic effects on BMI and waist circumference: a study in young adult twins. Int J Obes (Lond). 2009;33(1):29-36.
National Center for Health Statistics. Health, United States, 2007 With Chartbook on Trends in the Health of Americans. Hyattsville, MD: 2007.
National Center for Health Statistics. Prevalence of Overweight Among Children and Adolescents: United States, 2003-2004.
Phelan S, Wyatt HR, Hill JO, et al. Are the eating and exercise habits of successful weight losers changing? Obesity (Silver Spring). 2006;14(4):710-716.
Rosenstock J, Hollander P, Gadde KM, et al. A randomized, double-blind, placebo-controlled, multicenter study to assess the efficacy and safety of topiramate controlled release in the treatment of obese type 2 diabetic patients. Diabetes Care. 2007;30(6):1480-1486.
Saunders CL, Chiodini BD, Sham P, et al. Meta-analysis of genome-wide linkage studies in BMI and obesity. Obesity (Silver Spring). 2007;15(9):2263-2275.
Svetke, LP, Stevens VJ, Brantley PJ, et al. Comparison of strategies for sustaining weight loss: the weight loss maintenance randomized controlled trial. JAMA. 2008;299(10):1139-48.
Thompson WG, Cook DA, Clark MM, et al. Treatment of obesity. Mayo Clin Proc. 2007;82(1):93-101.
U.S. Food and Drug Administration. 21 CFR Part 357: Weight Control Drug Products for Overt-he-Counter Human Use; Proposed Rule. Federal Register. Vol. 55, No. 210;October 30, 1990.
Virji A, Murr MM. Caring for patients after bariatric surgery. Am Fam Physician 2006;73:1403-1408.
Wardle J, Carnell S, Haworth CM, et al. Evidence for a strong genetic influence on childhood adiposity despite the force of the obesogenic environment. Am J Clin Nutr. 2008;87(2):398-404.
Wing RR, Phelan S. Long-term weight loss maintenance. Am J Clin Nutr. 2005;82(1 Suppl):222S-225S.
Woo JG, Dolan LM, Morrow AL, et al. Breastfeeding helps explain racial and socioeconomic status disparities in adolescent adiposity. Pediatrics. 2008;121(3):e458-65.
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