What doctor recommend exercises should i do for a flat belly and bigger bum?

Lower abs: Situps, crunches, leg lifts all can work lower abs. See a trainer or pt for more specifics.

Tone abs/ build butt: For flat abdomen eat healthfully ; be physically active. Calories burned must > calories consumed. To tighten ab's: crunches, reverse crunches, exercise ball crunches, pelvic thrusts, lying leg raises, side bridge ; “bicycling” exercise on your back. Engage in regular aerobic exercise (i.e., running, swimming, nordic track, bicycling, kickboxing, walking, cross country skiing, hiking, etc.) >>.