I've been vegetarian for 7 months. if i suddenly ate lean poultry at one meal, would my gi system suffer/hard time digesting it?

Vegetarian: Our bodies are designed to eat all types of foods. There are certain foods that may bother you after having changed your diet for so long but they are usually going to be things very high in fat. That would possibly give your system a bit of a shock. Not likely to be a problem with lean chicken or fish. Remember, strict vegetarians should supplement with vit B12 that only comes in meat.