Drink a lot of water before you go. A pint of water (16 oz) is about a pound.

Practice meditation to control your heartrate. It may sound stupid, but this saved my ass a few times. A side-effect of starvation is that your heart doesn't hold up very well when you go from lying to sitting to standing; your pulse tends to skyrocket. Focus your mind on slowing it down.

Blood pressure is a tricky thing. Like your heartrate, your BP is negatively affected by starvation. Put a little salt (about a teaspoon per glass, more if I'm in a hurry and my stomach's not upset) in each of my glasses of water (not too much, 'cause it'll shock your system and make you retch) or I'll eat some celery with salt on it. salt raises your blood pressure for a short time and can help fool the doctor. If you're worried about the effects wearing off by the time you see your doctor, get a dark colored or opaque water bottle and bring it with you.

Dress warmly; even if they make you put on a paper gown, your body will hopefully retain enough heat that your temperature will be somewhat normal.

Do anything to make yourself weigh more: drink water, wear big shoes or a giant belt, put change in your pockets, anything. Ladies, some coins in your bra add weight, and you won't have to take off your undies for weighing!

If your throat is sore from purging, make an obvious fuss about it; say you've been
waking up with a sore throat for a week now. That way, when your doc checks, he/she won't be surprised to see redness and irritation.

Lanugo is a dead give-away. The razor is your friend.

Speaking of razors. Cuts, burns, scratches, bruises...anything you do to harm will ring alarm bells with any doctor. You know your body and you know how long it will take to heal. You also know when your doctor's appointment is. Make sure you're all healed up before you go see your doc, and if he/she notices any scars, say you've stopped and you don't plan on starting.

Your doctor is held to confidentiality. Anything you say during your appointment cannot be repeated unless you say so. So if your doc isn't fooled and confronts you about your eating disorder, tell him/her you want this to be kept confedential. This is especially important if you're under 18, since some doctors will go ahead and tell your parents anyway...UNLESS YOU SAY OTHERWISE. Don't try to deny it; you'll just make things worse.

Wear baggy clothing and lots of layers. This will hide weight loss and help keep you warm.

Pack a bag lunch to bring to school, and make sure people see you make it. Then, when you get to school, throw it out or give it to someone else.

Hide diet pills in your piggy bank. I did this for months and no on ever knew. Rotate where you hide them, too, just in case any get suspicious.

If you keep an ana or food journal, carry it with you at all times. Never leave it lying around for other people to find.

Purge in the shower, or turn on loud music to cover up the sound.

Clear your internet history after viewing pro-ana sites.

The opaque cup trick is very risky and should be done only in emergencies. Better to spit it out into a napkin; that way, if caught, you can say you bit into something gross.

Put band-aids over your knuckles when purging to help prevent scarring, which is a major indicator of an eating disorder.

If you know that you're going to purge (with laxatives or through vomiting), complain loudly that you feel sick. Make a big show of it. That way, if someone catches you, they won't be suspicious. Obviously this won't work if you do it constantly, though.

Using a nail-growth nail polish will keep your nails from becoming brittle, which is an indication of malnutrition. Or just paint your nails a dark color to cover it.

This may seem obvious, but it's difficult: don't constantly talk about food and/or your body. First off, people don't like it. Secondly, obsession and preoccupation with food and your body is sure to tip someone off that you have a problem.

Leave dirty dishes and food wrappers lying around the house; that way, people will think you've been eating. Do this enough and you may even be able to use it as an excuse to skip meals.

Say you have been planning on going for a run/walk and just save some for me later.

Try getting a high calorie drink then dump it out and replace wit with a low or no calorie substitute.

A great excuse that you can use only about once a month is your on your period and you have cramp/stomach ache/etc. Obviously you have to be a girl to do so. :P

Already ate at work/school/friends house/on way home

Haven't been feeling well. My stomach is kind of quesy; maybe I'll just have some hot tea and see if it settles.

Man, I've got a massive headache -- I'll just take a big glass of water and an aspirin.

Well, I had a really HUGE breakfast/lunch/whatever and I'm still full from that...maybe later.

Trying to eat healthier.

Go vegetarian/vegan.

Having really bad cramps because on period. Just not hungry.

Get in fight then refuse to eat.

On period and having really bad cramps.