having taught in the field i can assure you that it is both weights and cardio or aerobics. lifting weights doesn't burn as many calories as aerobics at the time you do it. however as you gain strength your metabolism increases so you burn more calories 24/7. as you increase your strength you will also burn more calories during aerobic exercise. both are important from a health standpoint. cardio is important for prevention of heart disease stroke diabetes and many other conditions. strength is important in reducing the affects of aging. as we age we loss muscle mass but a good strength program can reduce the loss. much of the reason we think we have to discontinue activities we once enjoyed is because of loss of muscles mass and reduction of aerobic capacity. while sit-ups help to strengthen abdominal muscles which helps prevent the common causes of back pain they do not help you lose belly fat. when you lose fat you lose it all over. however as with everything genetics comes into play in our lose of fat also. the other equation in the mix is food intake. without attention to a healthy diet and serving sizes you won't lose as much and will lose some of the benefits of exercise.
is aerobics a good exercise to loose fat in belly?