I know there are various posts about these but I've seen some that say 20 call is 1 syn but others say 20kcal is 1 syn. Also been looking at conversion from cal to kcal and seems to be 2 different types of calorie but guessing that in food terms 20 cal is the same as 20kcal
For food that has no free allowance, yes. So will work for treat stuff like chocolate, biscuits, crisps, etc. If it has any free food component, it's more complicated though.