Your weight loss doesn't sound bad to me but you are the best judge. I was in my normal weight range when I started SCD and lost 7-8 lbs. in the first 3-4 months and then levelled off, maybe lost another lb. in the following months (5'7").
Keep eating protein to keep your muscle up, something I look after with my DH and he doesn't have UC lol just a diet similar to mine. (I use "diet" in the medical sense of food intake not "diet" as in eating for weight loss which neither of us do).
It's amazing how little food we both need since eliminating carbs, grains, sugars and starches. We have plenty of energy. Keep drinking water too, very important to keep the colon healthy especially with eating more fiber.
Keep eating good fats also, those are "good" calories and I've found keeps energy up, good for skin/hair and (again) colon health. My every day oils are fish oil teaspoon and coconut oil teaspoon. I also cook with olive oil and use on salads as much as possible.
I've read that people whose natural diet is heavy in animal oil (far north Alaskan native Inuits) had almost zero cardiovascular disease before Western diet was introduced.
Personally I don't care about
scale weight as long as I feel healthy with energy and UC is quiet, which it is. I've got lots of clothes in various sizes from 10 years of UC and too superstitious to throw anything out just yet.
In remission April 2010 after 10 years of suffering and no remission ever
Jan 2010 started SCD diet (modified to remove dairy, fruit & juices)
Gluten-free=bleeding stopped in 3 days, 95% remission in 5.5 months on SCD
at 5.5 month stage homemade yogurt, hard cheese and some fruit OK
SCD Diet: Gluten/grain-free, starch-free, low carb, low-sugar
Supplements: tsp. fish oil, Vit D3 5000 with oil/fat, veggie juice, sunflower seeds, VSL#3, (4) Citrucel, (1) turmeric capsule, (1) calcium
Highly recommend: the book "Life without Bread" and the Specific Carbohydrate Diet
Rx: (6) balsalazide daily, mesalamine enema occasionally