Hiyah Elinor! Welcome
It's the day to day intake of extra, unnecessary calories, like soda, that you have to watch out for here... I think a teaspoon of 16 calorie jam won't make you into a blimp, but having a big dessert, like a candy or donut, etc... or corn syrup drink, ie: soda (is that what you mean by "squash"?) will...
I'm pretty sure that Reinhard addresses this on the NoS mainpage (see section on "borderline" foods, ie: yogurt, peanut butter and jelly sandwiches...)
If you have four tablespoons of jelly, I would rethink the amount!
As for fruit with a meal... That is exactly what we want to go for.. It's not considered a second course, but keep in mind that you need it all to fit on one plate... And the plate shouldn't exceed the side of a catchers mitt! LOL... If you have a substantial meal, with that fruit as the good filling non sugary dessert, chances are you won't feel the need to nibble away between those meals, and you will feel much more satisfied.
Good luck!
Peace and Love,

Deb