This is one of the many problems with the calorie in, calorie out line of reasoning that seeks to treat the human body like an automobile that uses fuel solely based on pressing the accelerator. What we're finding is that this isn't the case. For one, the body isn't 100% efficient, so a lot of calories in are lost in ways that aren't "burned." It's also likely that the body of a sedentary person is burning calories fairly inefficiently, so a change to being more active without altering diet will just cause that body to be more efficient in how it burns calories rather that burning fat or muscle reserves.
Calories in, calories out is an attractive concept, especially to scientifically-minded people who love the simplicity of deriving the answer by applying a fundamental law of thermodynamics. But the more we dig into the subject, the more we're realizing that it's a wrong-headed approach. The body is much more complex than that. We need a much more nuanced approach to nutrition, though "carbs are bad" seems to be a pretty good approximation of it.
24 miles a week is a decent bit, but it isn't that much. If you add 24 miles a week but eat a lot more, you will gain weight.
And about the food? Umm, it wasn't even close. Before the running, my idea of a snack was a little piece of cheese or a yogurt. After I started running, a snack was a Carl's Jr. Famous Star cheeseburger. Sometimes I'd order two. I became notable among my football player brothers-in-law for my capacity, regularly demonstrated, for out-eating them. My wife still talks about a particularly memorable restaurant visit where I basically ate 3 large, complete entrees. My calorie intake was ridiiiiiculous. Eating like that was both enjoyable and entertaining, and it didn't seem to interfere with my fitness, so I did it all the time.
And still I lost weight. Crazy. The body is a strange machine.