Hi Julie,
Have you read David's books? Especially "Sweet Poison Quit Plan". His latest "Eat Real Food" is a very good summary of it plus his other one "Toxic Oils" which is about the dangers of polyunsaturated fats, basically from seed oils. Other useful books are "That Sugar Book" and "The Fat Revolution"
As a general rule, anything with 2% or less "sugars" is OK. Sucrose [aka cane sugar] is 50% fructose and 50% glucose - it's a double molecule. Manufacturers are not required to indicate what's are included in "sugars". But by and large it's safe to assume that it is 50% fructose. So staying under 3%, say 2% max, means that for every 100g of the product you take in, you get 1g of fructose. Do that 10 times a day and you've reached your 10g per day allowance.
Percent = % = grams per 100 grams.
The exception to all this is yoghurt. It generally contains 4.7% of lactose-based sugar [aka milk sugar]. This metabolises as glucose so is OK. Therefore "sugars" in yoghurt are OK to say 5% . But watch out for low-fat yoghurts - when they remove the fat the flavour goes with it, and they replace that with salt and sugar. Most fruity yoghurts are loaded with sugar. Yoghurt is by its nature, pretty sour stuff. There is one brand of which has been sweetened by some sort of enzyme magic which is low in sugar AND tastes sweet :-) It's "Black Swan, Naturally Sweet, GREEK STYLE, Breakfast Yoghurt" which is also lactose free if that's a concern.It only comes in 500g packs and costs about $3 to $4.
Hope this helps :-)
JohnN