The Journal of the American Medical Association today released findings related to physical exercise and weight gain prevention.

The amount of physical activity needed to prevent long-term weight gain was generally seen as 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.”

The objective of the study was to examine the association of different amounts of physical activity with long-term weight changes among women consuming a usual diet.

The study involved 34 079 healthy US women (mean age, 54.2 years) from 1992-2007. At 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. The study examined physical activity and weight change over intervals averaging 3 years.

Results Women gained a mean of 2.6 kg throughout the study. Another 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 over a mean interval of 3 years, and those expending less than 7.5 MET hours per week gained 0.12 kg. 

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.

In my view its a pretty simplistic statement about what is required.  It only covers maintaining existing weight and doesn’t cover the overall benefits from a lesser amount of exercise regularly which is all that most women in today’s world can do.  For me, it’s all about consistency and if that is 30 minutes a day or 60 minutes 3-4 times a week, just getting out there is what matters!

Mr JoMo