June 28 - 29, 2007 Advisory Committee Meeting
Dr. Howley was introduced to discuss energy balance.
In contrast to the other clinical conditions that have been discussed, the
achievement of energy balance is equally dependent upon energy intake as well as
Two questions should be re-examined: How much physical activity is needed to
prevent migration from normal BMI to overweight BMI or from overweight BMI to
the obese BMI category; and second, how much physical activity is needed to
prevent weight regain after a large weight loss in formally obese individuals?
There appears to be more agreement in the literature regarding the latter
question than the former. Additionally, we should also address physical activity
recommendations within the context of weight-loss programs because of the
health-related impact of physical activity and the participants in those
programs that are independent of weight loss. There is considerable evidence
indicating numerous health outcomes from such interventions, and they should be
included as a part of this session.
Quantity versus quality also needs to be addressed. For example, it will be
helpful to know if there's a difference between moderate intensity physical
activity and vigorous intensity physical activity when the volume of exercise is
held constant as far as energy balance issues are concerned. In addition and
within this context, we should examine the role of gender and age as variables
that might impact the role of physical activity on energy balance, with special
attention to pre- and post-menopausal women and those experiencing sarcopenia.
And lastly, we should make sure that we review resistance training independent
of endurance training in this context.
Children, separated out between boys and girls, should be singled out in a
special category. Given that children are naturally in a state of positive
energy balance, a weight maintenance physical activity recommendation doesn't
make a great deal of sense. Additionally, the role of physical activity in
weight-loss programs for obese children should be examined.
The following special populations should be addressed relative to physical
activity and energy balance: Type 2 diabetes; pregnant women relative to healthy
weight gain; and populations with disabilities.
Finally, a couple of measurement issues should be discussed at some point.
Given that heavier individuals have a larger gross caloric expenditure for any
combination of exercise intensity and duration.
Energy balance should also address the relationship of physical inactivity to
energy balance in whatever populations for which those data are available.
Further discussion on energy balance included placing primary emphasis on the
issue of the relationship between physical activity and prevention of excessive
weight gain in those who are not already overweight.
Other population sub-groups that should be addressed include underweight
people and underserved and minority populations.