Nutrição em Educação Física e Esportes

Pessoal, precisamos de uma alma caridosa e poligrota para adotar esse resumo da JAMA, divulgado pelo ScienceDaily.

Amount of Physical Activity Needed to Prevent Long-Term Weight Gain

ScienceDaily (Mar. 23, 2010) — Among women consuming a usual diet, physical activity was associated with less weight gain over 13 years only among women of normal weight, according to a new study. The researchers also found that women successful in maintaining normal weight averaged approximately 60 minutes a day of moderate-intensity activity throughout the study.

The prevalence of overweight and obesity in the United States has increased dramatically over the past 2 decades, with 1 in 3 adults currently obese. "Because the average U.S. adult gains weight with age, developing ways to prevent unhealthful weight gain would help them avoid having to lose weight and then trying to maintain that loss. Compared with the vast body of research on the treatment of overweight and obese individuals, little research exists on preventing weight gain," the authors write. "The amount of physical activity needed to prevent long-term weight gain is unclear."

I-Min Lee, M.B.B.S., Sc.D., of Brigham and Women’s Hospital and Harvard Medical School, Boston, and colleagues examined weight changes associated with different physical activity levels in a study that included 34,079 healthy U.S. women who consumed a usual diet (average age, 54 years) from 1992-2007. At the beginning of the study and at years 3, 6, 8, 10, 12 and 13, women reported their physical activity and body weight. Women were classified as expending less than 7.5, 7.5 to less than 21, and 21 or more metabolic equivalent (MET) hours per week of activity at each time. Analyses examined physical activity and weight change over intervals averaging 3 years.

Women gained an average of 5.7 lbs. throughout the study. Compared with women expending 21 or more MET hours per week, those expending 7.5 to less than 21 MET hours per week gained .2 lbs., whereas those expending less than 7.5 MET hours per week gained .3 lbs, a difference that was not statistically significant.

"There was a significant interaction with body mass index (BMI), such that there was an inverse dose-response relation between activity levels and weight gain among women with a BMI of less than 25 but no relation among women with a BMI from 25 to 29.9 or with a BMI of 30.0 or higher. A total of 4,540 women (13.3 percent) with a BMI lower than 25 at study start successfully maintained their weight by gaining less than 5.1 lbs. throughout. Their [average] activity level over the study was 21.5 MET hours per week ([approximately] 60 minutes a day of moderate-intensity activity)," the researchers write.

"These data suggest that the 2008 federal recommendation for 150 minutes per week, while clearly sufficient to lower the risks of chronic diseases, is insufficient for weight gain prevention absent caloric restriction. Physical activity was inversely related to weight gain only among normal-weight women; among heavier women, there was no relation, emphasizing the importance of controlling caloric intake for weight maintenance in this group."

   Adapted from materials provided by JAMA and Archives Journals.

Journal Reference:

  1. I-Min Lee; Luc Djousse; Howard D. Sesso; Lu Wang; Julie E. Buring. Physical Activity and Weight Gain Prevention. JAMA, 2010;303(12):1173-1179 [TEXTO A SEGUIR]


CLINICIAN’S CORNER
Physical Activity and Weight Gain Prevention

I-Min Lee, MBBS, ScD; Luc Djoussé, MD, DSc; Howard D. Sesso, ScD; Lu Wang, MD, PhD; Julie E. Buring, ScD

JAMA. 2010;303(12):1173-1179.

Context  The amount of physical activity needed to prevent long-term weight gain is unclear. In 2008, federal guidelines recommended at least 150 minutes per week (7.5 metabolic equivalent [MET] hours per week) of moderate-intensity activity for "substantial health benefits."

Objective  To examine the association of different amounts of physical activity with long-term weight changes among women consuming a usual diet.

Design, Setting, and Participants  A prospective cohort study involving 34 079 healthy US women (mean age, 54.2 years) from 1992-2007. At baseline and months 36, 72, 96, 120, 144, and 156, women reported their physical activity and body weight. Women were classified as expending less than 7.5, 7.5 to less than 21, and 21 or more MET hours per week of activity at each time. Repeated-measures regression prospectively examined physical activity and weight change over intervals averaging 3 years.

Main Outcome Measure  Change in weight.

Results  Women gained a mean of 2.6 kg throughout the study. A multivariate analysis comparing women expending 21 or more MET hours per week with those expending from 7.5 to less than 21 MET hours per week showed that the latter group gained a mean (SD) 0.11 kg (0.04 kg; P = .003) over a mean interval of 3 years, and those expending less than 7.5 MET hours per week gained 0.12 kg (0.04; P = .002). There was a significant interaction with body mass index (BMI), such that there was an inverse dose-response relation between activity levels and weight gain among women with a BMI of less than 25 (P for trend < .001) but no relation among women with a BMI from 25 to 29.9 (P for trend = .56) or with a BMI of 30.0 or higher (P for trend = .50). A total of 4540 women (13.3%) with a BMI lower than 25 at study start successfully maintained their weight by gaining less than 2.3 kg throughout. Their mean activity level over the study was 21.5 MET hours per week (thkap 60 minutes a day of moderate-intensity activity).

Conclusions  Among women consuming a usual diet, physical activity was associated with less weight gain only among women whose BMI was lower than 25. Women successful in maintaining normal weight and gaining fewer than 2.3 kg over 13 years averaged approximately 60 minutes a day of moderate-intensity activity throughout the study.

Author Affiliations: Division of Preventive Medicine (Drs Lee, Sesso, Wang, and Buring) and Aging (Drs Djoussé, Sesso, and Buring), Department of Medicine, Brigham and Women’s Hospital, Harvard Medical School; Department of Epidemiology, Harvard School of Public Health (Drs Lee and Buring); Department of Ambulatory Care and Prevention, Harvard Medical School (Dr Buring), and Massachusetts Veterans Epidemiology and Research Information Center, Boston Veterans Affairs Healthcare System (Dr Djoussé) Boston, Massachusetts.

http://www.sciencedaily.com/releases/2010/03/100323161452.htm

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