Go to the kitchen and grab some snacks every now and then and take them to your room where they can quickly find the trash can and everyone thinks you've eaten.
Make a big deal of it when you do eat...make it really obvious.
Eat a small piece of strong scented food and people will think you've eaten something due to the breath issue!
When you start losing weight, wear baggier clothes to hide the loss.
When you get dizzy/head-rushes in front of people, LIE! Say you're ill or have had a real bad headache all day or are tired.
Wear foundation/concealer to give your dulling complexion a boost.
At meal times, when a plate is pushed in front of you, grab it and say you're going to eat it in your room...straight into the trash can.
When a 'treat' is bought for you i.e. a tub of your fav ice cream or candies, take small amounts out every now and then and throw in the trash, that way people will think you're always nibbling.
go vegetarian, than if they want you to eat, eat a few vegetables (these are lower in calories and healthier).
drink lots of water before going to the doctor. this makes you weigh more.
before the doctor have some salt in your water or on celery, salt aises your blood pressure a bit.