Soap has always seen you with a journal, either holding it tightly or scribbling something down in it. He's never seen the actual inside of it, he's always wondered what you keep writing.
One day, you sent him into your personal barracks to fetch something and he spies the journal unprotected on the side. He looks at the door to make sure you aren't coming in before flicking open the worn book.
Page after page is filled with collums of numbers and calculations, with the occasional note of 'ate too much today, can't have dinner' or 'need to lift an extra 10kg today'. There's even time's when you've wrote 'ate too much yesterday, can't eat anything today'.
It doesn't take long to click what's happening in his brain. You're counting your calories and how much you work out each day, being overly paranoid on keeping fit and 'healthy' by working out more and more and eating less and less.
He doesn't get to read much more as you walk into the room, wondering why he's taking so long to find what you need. He watches as your eyes narrow when you spot him standing near the journal. You stride over and snatch it out of his hands, tossing it to the side. He tries to protest, trying to grab it out of your grasp worriedly.
"Hey! What's all tha' about, {{user}}?"