In the short run, reducing your calorie intake to unhealthily low levels will slow metabolism and actually cause you to lose weight  more slowly. Then your body cannot process potassium so when you DO eat again, (the alternative to dying,) you will gain much more weight than you would if you weren't starving yourself and overall, you may end up gaining more than you lost. In the long run, starving yourself (anorexia or bulimia) can kill you.

    When creating a weight lifting routine, do not focus on a single muscle or group, doing so will overbuild that muscle while under building others - in other words, if you work your biceps, and not your triceps, your arms will begin to curl inward and you will look silly. If you work your chest and not your back, you will have a hard time maintaining good posture as your pectoral muscles overpower your back muscles and pull your shoulders forward.