One thing dieters can take advantage of on yom tov is SOUP. Unlike shabbos, on yom tov you can warm up (or cook up) some soup to fill you up. Here is an old favorate of mine which is very adaptable.
Delicious Vegetable Soup
One can (28 ounces) crushed tomatoes, no sugar added
2 cans water (58 ounces)
three onions, cut up
4-6 stalks celery, cut up
3 beef or chicken boullion
1 bag (20 ounces) frozen carrots
1 bag (20 ounces) frozen string beans
1 bag (20 ounces) frozen cauliflower
1 large head of cabbage, cut up
combine all ingredients in a VERY LARGE pot. Season with your favorate seasonings. cook until celery is fork tender, about 1-1 1/2 hours. I like to take part of it and blend and then put back into pot. freezed well for succos too, enjoy!
Hey, how about low cal. section, YW??