Do you have Celiac disease? If yes, STOP taking cereal, bread, peanut butter as all of these may lead to constipation. STOP taking stuffs that contain gluten especially wheat, no bread, no cake, no cereal.

Eat unlimited amounts of vegetables and small to moderate amount of fruits. Cut out all the crap carb and replace with complex carb. Remember to drink at least 3L of water too. Eat small to moderate amount of meat too (fat is good for constipation too, lubricant for intestine)

I have constipation problem too. What I did was drink warm lemon juice water/plain water in the morning (Must be warm, not cold), DO NOT sip them, GULP the whole thing continuously. This can help the water to reach your intestine effectively. Changing your drinking habit can help too. Then, eat breakfast like normal. (Again, NO cereal crap, no bread crap). Then, continue to drink some water and go to the toilet. DO NOT sit, do SQUATTING. It is effective for me.

Change your diet, drink more water, warm water in the morning and you are good to go.