How long do you have to be on a treadmill everyday to lose weight?

I've been using the treadmill everyday to lose weight I go on for 40 mins a day and it does not seem to be working I usually do 5000 steps at speed 3.0 I've also been using a full body vibration machine and doing Ann workouts. What kind of fruits and vegetables help you lose weight? And I also havent been drinking anything like pop or juice I've only been drinking water and milk. I have a lot off eggs and toast whole wheat wonder bred and raisin bran cereal the cereal makes me go to the washroom so I'm wondering why this isn't working I do eat other things then just that like salad etc.