In a recent article it was shown that exercise alone reduced abdominal
fat more then dieting did.  A part of the results can be seen below.
Women who exercised alone lost both hip and abdominal fat while those
dieting lost mostly hip fat only.

This is important because waist circumference and thus abdominal fat is
also a measure of the internal fat that promotes the metabolic syndrome
which is associated with increased risk of heart disease and diabetes
among other disorders.  A brief discussion of using waist measure to
assess metabolic syndrome risk is also below.

Thus any approach to reducing abdominal fat and higher risk levels is
far from most effective if exercise is not included along with dieting.
Exercise sets up belly fat cells to lose size more quickly then does
dieting alone.  With diet alone belly fat is some of the last to be
lost.

The exercise information:

Among a group of obese women who were placed on a regimen of calorie
cutting alone or diet plus exercise, those who exercised showed a
reduction in the size of fat cells around the abdomen. Women who only
dieted showed no such change.

In contrast, both groups trimmed about the same amount from fat cells in
the hip area.

The findings suggest that exercise may "preferentially increase" the
body's breakdown of fat cells in the abdomen, said lead study author Dr.
Tongjian You. The waist measure information:

Clinical Q&A Measuring Waist Circumference Benjamin A. Steinberg, BA;
Christopher P. Cannon, MD

Question: I've read a lot about the importance of "metabolic syndrome",
and I've also read that I can accurately assess almost all of my
patients' risk simply by measuring their waist circumference. So, should
I be measuring waist circumference in my patients?

Response:

Yes; careful statistical analysis has demonstrated that waist
circumference is not only an important and easily measured marker for
the metabolic syndrome, but it also captures new information. Why is
this? There are 2 reasons.

First, waist circumference is a good measure of visceral adiposity --
the body fat that is very metabolically active and that can contribute

to cardiovascular risk.