Its pumpkin, cream and sugar.
Honestly, just make it properly. Accept its a lot of calories, but at least its natural. Eating some cream and sugar once in a while won't kill you. Strange chemical non-food substitutes for those things might.
Make it right and enjoy it, just don't eat pie every day.
Whole grain flour or Whole wheat flour, Or you can use some natural yeast.
Eggs whites or egg yolks to keep them together
and Honey to make it sweet.