Question about account viewability

is it possible to allow others to see your daily food diary?

Click on "Settings" in the upper-right part of the site, then click Diary Settings. Towards the bottom of the Diary Settings page, you'll see "Diary Sharing", under which you can select Private, Public, Friends, or password-protected.

Edit: You can also just click here -> http://www.myfitnesspal.com/account/diary_settings