Will diet pills take the fat out of your butt and breasts ?

Not specifically: Commonly used "diet pills" work through appetite suppression and increasing metabolism. So if you end up consuming less calories than your body is utilizing, the result is weight loss. However, the weight can be fat, water or muscle. Where you lose fat will depend on genetics and your sex. Exercise and a healthy diet low in carbs is helpful. Multiple small meals per day and fluids are important.