Questions: I have always been an advocate for healthy eating and have tried to educate my children well in this regard. My thirteen year-old, however, likes to spend time with his friends hanging out at fast food places. I noticed that he’s getting a bit chunky lately. I don’t want to take away the fun he’s having, since we live in a small town where there’s not much to do for kids, but his weight gain concerns me. What should I do?

Answer: You are not alone. Most parents struggle at one time or another with their children’s eating habits. Teenagers especially, who are in the process of separating themselves from home and trying to find their own identity, will sometimes use food as a tool to assert their independence, simply because that may be an area where they have more control. This doesn’t have to give cause for alarm, unless someone develops serious eating disorders in the process.

I don’t think that’s the case with your son, though. Food may not even be the main issue. From the way you describe it, he just likes spending time with his friends and, unfortunately, that includes regular visits at fast food places – which is not a good idea at any age and certainly not for kids who are growing and are particularly in need of sound nutrition. If negative effects are already showing in terms of weight gain, it may be time to have a serious talk. You say that healthy eating habits are well established in your household. That should make it easier for you to remind your son of the importance of a balanced diet. It would be much harder if bad eating habits were common in your family and lifestyle changes had to be imposed on everyone.

Unfortunately, there is a certain urgency in all this. The damage your son is doing to his body right now may have serious consequences for his health later in life. In a few years, you will have less influence and control over your children’s lifestyle choices, and once they have money in their pockets and are old enough to drive, they are out of your reach.

Another obstacle that works against you is the omnipresence of fast food joints. Even in small towns like yours, they can be found on almost every corner. Health care professionals and policy makers have long urged legislation that keeps fast food outlets away from school grounds – obviously without much success. Worse yet, many schools depend on the funds they receive from snack food- and soft drink manufacturers for allowing them to sell their products on or near campus. Don’t expect for these policies to change any time soon.

So, what can parents in your situation do? As always, good communication is key. Your son is old enough to have a mature conversation about your concerns. At first, he may refuse to listen, but in my experience as a mother, nothing is really lost on teenagers, even if they pretend otherwise.

Question: My kids have discovered they like fruit drinks made at home from scratch. It’s all fresh fruit they are getting, so it’s supposed to be healthy, right? Should I be happy or worried?

Answer: Daily servings of fresh fruit are a good idea at any age and certainly beneficial for kids. Fruit is high in fiber and carbohydrate and has practically no fat, except for coconut and avocado (yes, that is a fruit too). The greatest benefits come from vitamin C and beta carotene and also from plant chemicals found in citrus fruits, berries, watermelons, grapes and apples.

Potentially negative side-effects of blenderized fruit drinks may be caused by the high sugar and calorie content. High quantities of fruit sugar can increase blood sugar levels to a degree that insulin secretion becomes elevated. This, in turn, may cause a “rebound drop” of blood sugar to a new low. The result is more intense craving for sugar. Overindulgence in high sugar drinks is one of the leading causes of obesity today. My advice to you: Everything in moderation – even the healthy stuff.

What about those Juice Smoothies? Same thing. Made with fresh ingredients, smoothies are nutrient-dense and high in vitamins, minerals, phytochemicals and fiber. The downside is that when you blenderize fruit this much, you do essentially the stomach’s digestive work in advance by breaking down the fiber and the chemical structure of the fruit. Therefore, the nutrients become more readily available for absorption. If the digestive process is cut short, a higher concentration of sugar from the fruit reaches the blood stream and elevates the blood sugar level quickly. The same effects occur that I described above.

Also, most smoothies contain additional ingredients other than fruit, such as milk or soy. Typically, they are 20 to 32 ounces in size and can contain as many calories as a full meal. Some have a high fat level from added milk or yogurt. Read the ingredients list carefully before you buy commercially produced fruit drinks and smoothies and watch the serving sizes.

Timi Gustafson is the author of “The Healthy Diner – How to Eat Right and Still Have Fun.” Find more tips for a healthy lifestyle in her book which is available at local bookstores, at www.amazon.com and at her blog. Visit timigustafson.com to read many more Glad You Asked™ Q+A sessions and post your own questions, comments and suggestions.