Like Cherry, I tend to buy the tubs now so you can have that little bit more than you would in a sachet.
It tells you on the jar to have three spoonfulls so that should just be the standard 40 calories, shouldn't it? For me it makes a better mug full than a sachet.
I currently have a jar of Cadbury's plain chocolate highlights but I don't like it on its own (too bitter) so I am having two spoons of Options and one of Highlights and it is working well