Hi,

I agree with watersidhe, it is very difficult to say exactly how long it will take before your body decides to go into starvation mood. It's no good to go without food anyway.....well, when I was flying and waiting at the airports a lot I simply had to bring some cheese/sausage/nuts with me. High fat stuff plus lots of water. You can even grab a hotdog and toss the bun......
Try to eat and go back to regular habits as soon as you can!

All the best

Alina