Long-term secret is portion size, exercise and healthy food. Eating an Oreo won't hurt you. Eating 10 Oreos is not so great.
I eat Grandma's cookies on rides at times.
You can ride OK in 45F - some folks ride lower temps, but just about anybody can ride at 45F, especially if the sun is out. It is just a matter of proper clothing and attitude - believing you can do it. Does it get to 45F in St Louis in the winter months? Perhaps you could really ride now. I ride in every month in Denver, CO, and I am not a fanatic cold-weather rider in any way.
By the way, great job on losing 60 pounds! That is very impressive.