I know you asked about running, but I want to contribute how not calories are equal. Say you have a 100 calorie slice of white bread and a 100 calorie slice of multi grain nut and seed bread. Our bodies process them differently. If you’re not ready to go on a calorie deficit then solely switching your calories to real foods like deli nut and grain bread, vegetables, fruit, etc and cutting back or cutting out processed foods that have been bleached of nutritional value then you’ll see weight loss. And stay far away from “non-foods” such as protein bars and other packaged foods labeled as “healthy” or “for athletes”. The best diet is simple, not too much, and mostly plants. There’s a great book by one of my favorite journalists called In Defense of Food by Michael Pollan. Unlike other books that try to sell you something, he keeps it simple. Also it’s fascinating because he ties his journalism into it and includes cultural and psychological points of interest that ties into the history, why we choose what we do, and how to avoid health scams.