>>>
on your health. our
lifeline
report and tricky relationship between exercise and
weight loss
, especially for
women
. a major new study found without making changes in diet,
women
need a lot of exercise just to keep their weight stable. our chief science correspondent
robert bazell
has our
lifeline
report.
>>
reporter: the results of 13 years of studying the exercise habits and weight of some 34,000
women
in the anti-age sponsored
women
's health study will come as no surprise. if the weight is already on, it's almost impossible to lose it.
>>
among the
women
who are overweight, obese, there was no relationship between
physical activity
and weight change
over time
.
>>
reporter: researchers found in middle-aged or older
women
who eat a regular american diet, exercise, even
60 minutes
a day, does not prevent
weight gain
over the years. the only exception was
women
who started out with what is considered ideal weight, say 145 pounds or less for a 5'4" woman. exercise helped those who started thin to stay thin. that's little comfort to
vicki
jones, who like almost everyone else seems to keep on the extra pounds no matter how hard she tries.
>>
it's frustrating because i work very hard to try to lose the weight.
>>
reporter: when she was young,
vicki
, a pastor's wife was rail thin, but after the birth of her son the weight came on year after year. scientists are concerned this latest news may prompt many
women
to give up on exercise.
>>
that is absolutely not the right message to take. we have lots of studies, lots of data clearly showing any amount of
physical activity
is good and more
physical activity
brings additional
health benefits
.
>>
reporter:
vicki
jones has decided she is not giving up.
>>
it would be really nice to come up with a way to make this happen where i'm just not exhausting all this
energy
without getting the results i'm looking for. lucky shot.
>>
reporter: the experts say, even though exercise is beneficial, the quest for easy
weight loss
remains elusive.
>>
still 175.
>>
reporter:
robert bazell
, nbc news, new
york
.
>>
there is more on this study and this topic on our website nightly.msnbc.com. speaking of food, it may be the
“ ”