Hi, I've had 2 EMG's done on my legs, feet, hips and lower back. I was told I could eat normally before the test, as long as I don't mind lying down after eating. I was told to avoid blood thinners like aspirin, and to avoid nerve stimulants like caffeine.

As to what to expect you will be mostly naked, my dr let me keep my underwear on, and just shifted it when he needed to. The first part they put a flat sensor like thing on you and sort of send an electrical impulse through it. It doesn't so much "hurt" as feel like a static shock multiplied by like 50-100 depending where on you they are doing it, and how high the voltage it. (I personally, am very sensitive so this was not comfortable at all for me, but for someone with less sensitivity to pain it won't be as bad.) The next part, if they decide they have to do it is when they stick small needles into areas along the nerves and test conductivity by asking you to contract your muscle... usually by moving your limb. This is weird, and can be painful, once again depending where the needle is. (And yes there might be a little blood involved, but no more than if you got a small cut- total from all the needle sticks)
Afterward your muscles might feel achy, tight or a bit sore... mine even felt a little tired. The thing that helped mine the most was rest. Overall, it is not the most pleasant experience, but it isn't the worst either.