>I don't think young toddlers know what a calorie is, or how many they need - or the difference between a good calorie and a bad calorie.

Perhaps also worth noting that obesity is a relatively new problem in Thailand. While the obesity rate is rapidly increasing, it was below 5% only 20 years ago. It's not a problem they've been dealing with for multiple generations the way we have in the West, and the grandparents of today's children grew up in a time when hunger was a much bigger problem than obesity.