From this article The best exercise for controlling belly fat, this quote:
"Men who did regular weight-training had less gain in their waistline (-0.67 cm) over the 12-year period, compared with those who participated in moderate-to-vigorous aerobic exercise (-0.33 cm), or physical labor from daily life such as yard work or stair climbing (-0.16 cm)."
Losing muscle is part of the aging process. As adults we lose about 5 pounds of muscle a decade, and with that comes a lower metabolism. If you don’t cut back on the calories you will replace that muscle with fat.
If you attempt to lose weight with a severe caloric restriction your body received the message that it's not receiving enough calories to survive. The body will catabolize lean body mass to lower the body’s metabolism to compensate for the decreased caloric intake.
If you diet and also strength training the body, instead of losing muscle mass, you will maintain and even add to the muscle mass and thereby increase metabolism.