I've been there and still working on it.
The best things that have helped is to try not to talk about it but to sneakily change their diet. The SCD Diet (Specific Carbohydrate Diet) was and is the biggest help.
The meals have just changed and I don't tell the kids or friends that I have. Emphasize vegetables- at snack time you'll hear me say: Pick a vegetable or protein you've had enough carbs! Snacks tend to be home cooked and include fruits, veggies and meat. There is not a single junk food in our house.
Dinner just stopped having carbs everyday. I make potatoes or pasta very infrequently and always, always have vegetables. I try to get them raw veggies too. They don't like salads (age 13, 17) but will each veg. slices, sticks etc. So dinner just is veggies and meat most nights.
They can have unlimited fruit and I spend a lot of money on fruit. Breakfast I try to sneak veggies in, quite often it is last nights dinner, a meat and veggie meal.
The SCD diet is radical but after 20 years, it really seems to be the only treatment that really worked for me personally (with my yeast issues).
I'm still searching for answers for my kids because the battles over food choices are harder now that they are older. But their diets are much improved and symptoms less even though I don't do a 70% vegetable diet.
The diet changes I made when the kids were very young (like 6 and 2 yrs) they accept the most. They resent the changes/improvements I've made over the years but slowly adjust to them.
The kids haven't had any skin yeast infections since I started moving towards the SCD diet. Also giving them vitamins everyday really, really helps. Vitamin C is a miracle worker for them. I give the 13 yr old who is only 70 lbs 1 gram morning and again at night. More when he is reacting or sick.
The constipation improves with diet changes but we feel in our family it is also due to yeast and other parasites. So we are still working on that angle while supplementing with Vit C and Magnesium to keep the bowels moving.
I throw away sugary stuff the kids are sent home with, or loose it until they forget. At strangers' houses we do the best we can, you can always try to end run by saying if the kid doesn't eat the dinner they don't get dessert. Or a rule that most families accept, (like no soda with dinner) to keep Sugar stuff down. If at the house of a non-believer I just take the nutritious mom route to avoid problems.
And yes, mine get Sugar when they go to parties but not as much as they could.
Hope this helps and for the light colored stool it can mean the liver is not working well. Herbs seem to be the best for kids, can't see coffee enema's or Liver Flushing for them though it works for me. I haven't tackled that issue with the kids yet I'm still doing diet improvement (more veggies for more alkaline) and parasite cleansing. Try reading over on the Liver Flush Forum .