But the daily mile is not what will push you into overtraining. It’s just 7 miles a week. Training hard in calorie restriction is IMO a horrible idea though. You would need to make sure to burn as little carbs as possible and not do any workouts. Basically dedicating a block to losing weight instead of improving your running. Might still get faster, weight is a factor in running

But exercise along with calorie restriction will keep you from losing muscle mass and so your weight loss will be more from fat. I agree though, no need to train hard during calorie restriction.