This is great advice, she is not going to change to a healthy diet overnight if she is used to eating simple carbs and goodies.
In addition to having her just cut out a small amount of 'rubbish' carbs/week, have her switch to sweets or different carbs, so have HER starting to look for the whole wheat option/ezekiel bread.
Also, advice her not to eat anything that has glucose, glucose syrup, dextrose etc in it, but if it is sweetened with apple juice, grape juice, honey, barley malt, rice syrup, maple syrup (not refined if possible), agave syrup, date syrup, evaporated cane juice (you can also buy a lot of these on their own as sweetners).
They are all still sugar, but less refined, possibly have a few more good things in them, sometimes not as sweet, and a good way to wean yourself off sugar.
Sugar is a tough one to get off.
What is her fat intake like?