Did We Lose Weight Summary:
The American Heart Association
(AHA) recommends at least 30 minutes of moderate intensity activity five days a week for healthy adults.
Unfortunately, this study conducted at the University of Pittsburgh,
which involved 201 women ages 21 to 45, found that
this was not enough to avoid weight gain in the
long-term. The study concludes that people
should try to engage in more exercise or
physical activities (above the AHA baseline
recommendation) in order to prevent weight gain
in the long-run.
What does this mean to you?
If you currently engage in AHA recommended
amount of exercise, this study tells us that you will
need to exert more effort and time for exercise
or physical activities to avoid weight gain in
the long-term. Not too
encouraging but that is the reality of the
situation. What we suggest is that you start incorporating more physical activities
into your daily lives in order to burn those
calories. For example, instead of just
sitting or standing while watching television,
why not multi-task and do some exercises. Better yet, enroll in a gym and let the
power of group dynamics push you to
more intense exercise to keep the weight off.
PITTSBURGH, July 28,2008 -- Standard recommendations
for 30 minutes of exercise five days a week
won't cut it to sustain weight loss, researchers
In addition to cutting calories, women needed the equivalent of 55 minutes of activity five days a week to maintain a 10% body weight loss over two years (P<0.001 versus those unable to sustain weight loss), reported John M. Jakicic, Ph.D., of the University of Pittsburgh, and colleagues in the July 28 issue of the Archives of Internal Medicine.
The prospective intervention trial highlighted the difficulty of maintaining weight loss as only 24.6% of participants achieved a 10% or more loss through two years, the researchers said.
Because most people don't stick with an exercise regimen, increases in nonexercise activity and other changes are needed to solve the obesity epidemic, Warren G. Thompson, M.D., and James A. Levine, M.D., Ph.D., both of the Mayo Clinic in Rochester, Minn., said in an invited commentary.
"We believe that 2,000 kcal per week of physical activity can be achieved through a combination of strategies," they said, "including increased formal exercise, a modified work and school environment that allows for movement while working and learning, and a modified home environment with less television and more movement."
For healthy adults, the American Heart Association recommends at least 30 minutes of moderate intensity activity five days a week (150 minutes per week).
But because growing consensus suggests more may be necessary for long-term weight loss, Dr. Jakicic and colleagues studied the amount and intensity of exercise necessary for varying levels of weight loss at two years.
The study included 201 women ages 21 to 45 with a body mass index of 27 to 40 kg/m2. All were sedentary at baseline, exercising less than three days a week for less than 20 minutes.
The intervention included restriction to 1,200 and 1,500 calories per day and randomization to four groups assigned to burn 1,000 or 2,000 calories per week in either moderate or vigorous physical activity.
Group meetings focused on strategies for modifying eating and exercise habits. Participants also got telephone calls once or twice a month to encourage adherence to the intervention.
Dropout rates were relatively low for all groups from 17.1% in the moderate intensity and expenditure exercise group to 6.3% in the vigorous intensity, high expenditure group.
None of the intervention groups were able to stick with the program significantly better than the others.
Weight loss was similar across groups, peaking at an average 8.9% of initial body weight at 12 months and then falling to an average 5% by two years.
Dietary fat intake was similar between intervention groups (P=0.38), and total caloric intake was not different between those able to maintain significant weight loss through two years.
Women increased their leisure time physical activity significantly in the first six months of the intervention -- by 1,235 kcal a week -- but this dropped to 720 kcal a week above baseline by the end of the study.
However, the higher the level of physical activity the more patients were able to achieve at least 10% weight loss.
The percentages achieving that level of weight loss were:
37.8% with vigorous intensity, high duration activity
31.7% with moderate intensity, high duration activity
20.5% with moderate intensity, moderate duration activity
20% with vigorous intensity, moderate duration activity
In a posthoc analysis, participants who were able to sustain a loss of 10% body weight or more at two years reported getting 1,835 kcal a week of physical activity, which was about 275 minutes more than at baseline compared with those who lost less (P<0.001 versus those who lost less).
The researchers highlighted that this was the amount above and beyond patient-reported baseline activity levels, although the participants were essentially sedentary before the intervention.
The intensity of the activity didn't appear to affect weight loss, but as Dr. Jakicic's group noted, "this may have been a result of lack of adherence to the prescribed intensity during this study."
Limitations of the study included self-report of physical activity and absence of a group using diet alone.