I just bought a treadmill i need tolose weight any suggestions?

okay i just bought a proformer treadmill and i (need) to lose weight for my blood pressure and stuff like that i relly need some suggestions on snacks and healthy food (shoppin) tommrow!!!! do you have any suggestions on how i can lose weight steadily and fast but not to fast in a healthy way o also im scared if i lose weight that i will have flabby skin i dont have any weights so any other helpful tips would be great thanks