D wpuld be the best answer because dieting is the most important thing when losing weight. If she does add weight training the body fat will decrease and turn into lean muscle.
I believe the answer your looking for is the "frontal" lobe, though this is if you just want the lobe of the brain. The frontal lobe is responsible for giving the traits that define our personality and who we are are. If you want to be specific though it is, I think the "Amydalga" is the more specific answer
Nutrition is important in achieving total fitness because it involves eating the right balances of vitamins, minerals and fiber which are essential in maintaining fitness. In addition to physical exercise, nutrition is important in improving overall health and maintaining the right and appropriate weight. When it comes to total fitness, one must take care of the body, mind and spirit and nutrition is part of taking care of the body and mind.