Runners can eat whatever they want.
You run a lot.
That's how you stay so thin.
False. False. False. If running a half-marathon taught me anything (it taught me a lot of things), it taught me even more the importance of nutrition. And I'm talking eating right, eating a lot, and eating to run, not running to eat.
I found out very quickly that running made me, hungry very hungry. I sometimes tried to practice "self-control," but then I kept reading about how running can damage your hormones, lower your immunity, create injury, etc. if I didn't eat right. So I ate. A lot. Like handfuls of granola and nuts after my morning bowl of oatmeal. Like lots of red meat. (Thanks to reading Run Fast, Eat Slow.) Like protein bars and gels, which I know can "make you fat," (but they didn't-they gave me energy). I decided that even if I did eat so much I gained weight, I'd rather gain weight and run than not run and not gain weight. (Running is good for my mental health, I've found.)
I wanted to eat sugar, but it seemed to lower my immunity and made me feel yucky. So I turned to whole food and more savory stuff. I sometimes wanted to skip carbs, but that didn't work so well, so I added in more carbs. I often stayed up late eating a big nighttime snack to make sure my belly was full and ready to run the next morning. I found out the hard way that I needed to stay on top of my long run hunger (e.g. eat on a schedule/before I was hungry) to avoid an all out binge. I ate when I didn't want to and sometimes to the point of feeling overfull, because I knew I needed it. And on the day I ran my half-marathon, I ate more than I think I've ever eaten before, but I did it because my body kept telling me it was hungry, so I knew I needed the fuel.
Can runners eat whatever they want? I'd argue not. Does running make you thin? I'd argue no in that case, too. In fact, my predisposition to being thin makes me a worse runner in some ways because I have less muscle and no fat stores to use as a reserve for days of extra miles.
So let's dispel the myth that most runners run to eat. Maybe some do. I don't. I eat to run. Extra hunger and the chance to indulge is maybe nice sometimes, but overall, running is about taking better care of myself. And that means eating better. Sometimes more. Sometimes less, but more focused on nutrients and having good energy overall. Otherwise my running is not going to get better. And I, as long as the Lord allows, want to keep progressing in this sport if I can.