I blogged last fall about a survey that found parents are more comfortable discussing sex, drugs and alcohol with their kids than addressing the should-be-less-weighty topic of their excess pounds.

Why is it so hard to talk about weight with our kids? It shouldn’t be so challenging to say to a child, “Those extra pounds you’re carrying around are hard on your body and not so good for your health. Let’s see what we can do together to change that.”

But we’ve managed to layer everything related to weight — our own and our kids’ — with all kinds of emotional, cultural, psychological and otherwise unhelpful baggage that it seems impossible to cut to the practical quick.

But a new guide for parents does just that. “Weigh In: Talking with Your Children About Weight and Health,” produced by the STOP Obesity Alliance and the Alliance for a Healthier Generation, focuses on excess weight as a health issue that requires effort to manage. The guide acknowledges the many forces — a parent’s own obesity, misunderstanding of BMI measures, body image, bullying, cultural norms that favor larger body shapes — that work against such a pragmatic approach and helps parents navigate around them. In fact, it provides scripts that you can follow, providing just the right words for you to say.

For instance, consider the sticky situation that occurs in families in which one sibling is of normal weight and another is overweight, a scenario in which teasing often takes place. (The guide cites research showing that nearly half of overweight females and a third of overweight males report having been teased by family members.)

The guide suggests that a parent in such a family might take the teasing sibling aside and say, “I don’t know if you know this, but your sister is dealing with a health issue,” and “Like some of your friends who may have asthma or trouble concentrating, your sister carries around too much weight and that can hurt her health too.”

And, the parent might add, “What’s most important for us as her family is that how much she weighs is not a measure of who she is as a person. Because we know she is (FILL IN with positive attributes, e.g., caring, a good friend, smart, a hard worker).” From there, the sibling can be enlisted to help think of simple, easy-to-monitor-and-implement things the family can do together to help promote a more healthful lifestyle.

Press materials announcing the release of this “conversation guide” note that the document  “was created and reviewed by experts from a cross-section of fields including pediatrics, obesity research and psychology, but most importantly, these experts have children of their own.”

That last bit is important. Throughout, the guide keeps the temperature low and promotes compassion and a spirit of cooperation; there’s no pity, condescension, criticism, guilt or anger here.

Have you had “the talk” with your overweight child? What did you do right — and what do you wish you had done differently?