Sit ups alone are not an effective method for losing weight. Sit ups are great for building core strength and for toning the muscles of the abdomen. However, they generally do not burn body fat or help shed pounds effectively.
According to Fit Watch, one effective way for dieters to lose 15 pounds is to boost their body's metabolism by drinking plenty of water and eating protein-rich foods. Regular exercise should also be included as part of any weight-loss regimen. Exercises that build muscle, such as sit ups, have their place, but aerobic exercise is also important for burning fat. One useful strategy is to alternate strength exercises with aerobic running.