My mother in law recently found she has cancer and she got all sorts of blood work done at this natural health clinic . She had asked me to go over the results with her and explain some of the numbers. In looking at it, I also saw that she was just over the border into diabetes. So I talked to her just a little bit about fasting…for both the cancer and the diabetes. She looked over the info from Jason Fung I gave her, but she still had a lot of questions. We had arrived yesterday at my sister-in-law’s house. She and her three kids homeschool, and are doing the THM diet. So I got the idea to do a presentation for all of them on low carb, ketones, insulin resistance, intermittent fasting. For the kids (they are 12, 14, 16) I gave a lot of general info on food…like what types of food are primarily carbohydrates, etc. I had my blood glucose tester, so they had fun testing blood sugar before and after meals. A lot of the info was from the Grain Brain book because the parents are concerned about losing memory as they age. It must have gone fairly well, because everyone was psyched to start fasting…though I had to caution the 12 year old about doing much extreme fasting since he’s still growing. They went from “the worst thing you can do is to skip a meal” to planning how to regularly skip meals 
Gave a Keto Talk Yesterday
That is a wonderful thing to do for your in-laws… And what a great way to get them all excited and motivated together. So inspiring!
I don’t know about fasting, but a google will show, keto is being used with some mainstream cancer treatment
Sorry to hear about your mother in law’s diagnosis. I don’t know about kids/teens fasting, but great that you provided them with some accurate nutrition education. They certainly won’t get it in school- even if they go to med school!
Rather than have teens fast, I think they should learn how to maximize nutrient density, and how and why to avoid toxic addictive foods. I wish I had learned that when I was young…
for kids, stopping their metabolism from being damaged in the first place, would go a long way. Cutting out sugars including fruit juice and going easy on wheat. Go back to the 30-40% carbs of yesteryear.
simply doing that will turn around the obesity and T2 epidemic. keto if the family wants to.