You need to actively teach your child about nutrition so he can learn to make good decisions. The way to do that is to select items from the grocery shelves based on what the labels suggest is healthful instead of on what advertisers say is delightful. When your child urges you to buy a certain brand of cereal, study the label carefully instead of dismissing it out of hand. Point to the words fat and calories and their associated numbers so he understands why you're saying “no” and can learn to check labels. Verbalize your thoughts so your child can hear how to make nutritional decisions, and involve him in the search for the products you approve of: “Hot dogs made from beef contain too much fat and cholesterol. We need to find a kind that is filled with turkey, chicken, or vegetables. We need a fresh vegetable to go with them. Broccoli is high in calcium, which is good for your bones, and you're growing so fast right now. Or you could get your calcium from a glass of milk and choose a different green vegetable. Which would you prefer?”

As soon as your tween is old enough to read labels, send him off to find a kind of cereal or loaf of bread he likes that seems to him to meet the nutritional criteria for good health. If he comes back with a product that doesn't fit the bill, don't chastise him. Maybe he's trying to slip something past you or maybe he just doesn't understand. Don't assume the worst. Just say, “Let's look at the label together.” Then point out the figures for fat, sugar, and salt, and send him back to look for another brand.

If one of your youngsters lacks self-control, don't worry about the hardship for siblings who can keep their hands out of the candy bowl. Family members need to help and support one another. Maintain a junk-food-free household to help the child who can't moderate his own food intake, and praise the others for contributing to their sibling's welfare. Even if their sacrifice is not voluntary — and especially if it's not voluntary — they deserve kudos for helping out.