How's The Diet?

Another Prompt Meme Fill! Prompt: When Sherlock asks about Mycroft's diet he's not trying to snark or tease - he's genuinely worried. At one point in time Mycroft had an eating disorder which actually put him in the hospital - ever since Sherlock's been asking about his brother's diet and seeing if he's eating enough. Trigger Warnings: Anorexia. Angst. Eventual Mystrade.