I invented an easy version of split pea soup that I think is relatively healthy and low-ish carb. I wouldn't consider it low calorie though because bacon is so high fat. (I've had a hard time figuring out how many calories are in uncooked bacon, i.e. bacon including all of the fat (rather than bacon with the fat cooked off), so i don't know the precise calorie count). Here it is:
1 pound bacon, chopped into small pieces
5 stalks celery, chopped
3 onions, chopped
Sautee these w/ garlic powder and pepper. Then add water and boil. Then add 1 cup split peas. Cook 1-2 hours until the peas are dissolved.