Laxatives vary based on how they work and the side effects they have. Certain stimulant, lubricant and saline laxatives are used to evacuate the colon for rectal and bowel examinations, and may be supplemented by enemas under certain circumstances. Sufficiently high doses of laxatives may cause diarrhea.
Most vegetables, with the exception of onions, mushrooms and tomatoes, should be blanched briefly before being dehydrated to limit discoloration and the risk of food-borne illnesses. You can dehydrate tomatoes, carrots, beets, greens, beans, squash, onions, peas, celery, corn, pumpkin and broccoli with good results.
Only take as much as you're going to need to eat and nothing more. Eat that, and drink plenty of water. If you end up getting dehydrated during the day you'll worsen your situation as well. When you're choosing what to eat, you'll want to start out with a healthy breakfast.