Losing your colon does not mean you will lose your ability to absorb calories. Calorie absorption takes place in the terminal ileum of the small intestine. So weight loss should not be a problem except for immediately following surgery. As for dehydration it can be a problem for some people; I only am careful and conscious of hydration when I am exercising. Otherwise I drink very little. Each person is different, you will have to learn how your system will behave.
dx proctitis in 1987
dx UC in 1991, was stable until 1998
1998 started prednisone, asacol, pentasa, nortriptylene, ativan, 6MP, rowasa enemas and suppositories, hydrocortisone enemas, tried the SCD diet, being a vegetarian, omega 3s, flax, pranic healing, yoga, acupuncture, probiotics
2000 lost all my B-12 stores and became anemic
2001 opted for j-pouch surgery- now living life med-free