Since i have an ileostomy and no colon does that mean i cannot get fat?

Absolutely not true: The colon does nothing but reabsorb water to maintain your fluid balance. Fats, sugars are absorbed in the small intestine and assuming you have had none of that removed. You can easily gain weight if you eat incorrectly and do not exercise.

No: You have to watch your diet. Weight loss after loss of colon is not common, it is common after loss of small bowel or stomach.