Question: Our grandson weighed 6 pounds 10 oz. at birth. He is now 3 months old and weighs 18 pounds. The pediatrician says, "Don't worry. He'll run it off when he starts walking." The doctor has not given the parents any advice on feeding schedules. They pop a 6-ounce bottle into the baby's mouth every time he makes a noise. I'm worried that the baby is gaining too fast and developing bad eating habits that will make him a fat child or obese adult. —Grandma, address withheld

Answer: I share your concern. Your grandson's pediatrician is partially right about the leveling off that often occurs once a child begins to walk, but not if the child is already too heavy to get around.

It's a lot easier to prevent obesity with healthy eating habits and physical activity then it is to treat it later on. We are learning that "fat babies" are likely to become fat children who are likely to become obese adults. And the trouble with obesity is that it all too often brings with it serious medical problems such as high blood pressure, diabetes and its complications, heart and lung disease, an increased risk for cancer and even orthopedic problems.

We are in the midst of a pediatric obesity epidemic in our country. As a result, we are now witnessing the first generation in human history whose life expectancy is already shorter than that of their parents!

So, we are all concerned with preventing obesity these days. Your concern, though, about over-feeding a very young infant whose cries are misunderstood provides an all-too-often overlooked insight into one of our earliest opportunities for preventing obesity.

There are many risk factors for childhood obesity, and children are exposed earlier than we may think.

Genetics play a role, but so does the fetus' intrauterine environment: Though a certain amount of maternal weight gain during pregnancy is critical for the new baby's health, an excess puts that baby at risk for obesity later on.

Poverty is also a major culprit. Fatty foods and sugary sodas are cheap and filling, while foods high in protein and complex carbohydrates are expensive and scarce in poor neighborhoods.

The amount of television children watch, and the presence of TV sets in their rooms, correlates with their risk for obesity, partly because TV watching cuts down on time for running around, and partly because of the ads for sugar-coated cereals, cakes, fast and fried foods.

In many parts of our country, where school gym programs have been slashed, parks are unsafe or non-existent, and freeways have taken the place of sidewalks, children are less active than ever before.

The ways we eat also put us at risk — grazing, eating while watching TV, or standing up to wolf down fast food — all interfere with the natural signals from our guts to our brains that say, "That was good. Enough already."

Early feeding interactions are babies' first chance to learn to pay attention to these signals, and to distinguish them from other feelings and physical sensations.

Grandparents can't tell their children all of this, because they'll feel hurt, they won't listen, and they'll never ask for advice again. Of course your children want the best for their child as much as you do, even if they have not yet learned that even at three months, not every peep means, "I'm hungry."

You may, though, be able to help them observe the baby to discover the other needs that he may be expressing, and the way his other interests at this age can be enlisted when he begins to fuss. Parents learn more from their baby's behavior than from anything any grandparent can say.

Show him an attractive toy just as he's beginning to fuss and seems hungry to them. But don't explain what you're doing. His parents might be rushing to feed him because they don't know anything else to do for his protests. As he sees the toy, I hope he will quiet down, look interested, shape his hand to try to reach out for it. When you hand it to him, he'll examine it, mouth it.

This new reach may be so exciting that he'll continue to reach out for plastic spoons strung on a safe line across his crib. Prop him up to let him reach them and play with them. As his parents see that he can now begin to reach and play in periods instead of feeding, they may be so excited that they may begin to see that their baby already has several different cries, and that he is not always hungry.

Even in the newborn, there are six distinct cries, expressing hunger, but also boredom, discomfort, pain, letting off steam at the end of the day, and fatigue. All are different. New and maybe overwhelmed parents will lump them all into one — hunger.

As a result, your grandchild may be fed every time he tries to express himself. If you can simply show — without telling — how he responds to other things at such times, without criticizing them for their passion, you may have a chance to help them learn many ways to help him in the future, and he won't need to become obese.

Learning to understand and respect a baby's earliest cues is our first opportunity to teach that baby how to recognize when he is hungry, when he is full, and when he has other feelings that must not be mistaken for hunger.

Obesity prevention begins way before many people think — even before solid foods are first introduced!

For more help with early feeding challenges and suggestions on how to prevent childhood obesity right from the first, read our book "Feeding Your Child The Brazelton Way," Da Capo Press, 2004.

Questions or comments should be addressed to Dr. T. Berry Brazelton and Dr. Joshua Sparrow, care of The New York Times Syndication Sales Corp., 609 Greenwich St., 6th Floor, New York, N.Y. 10014-3610. Questions may also be sent by e-mail to: Questions of general interest will be answered in this column. Drs. Brazelton and Sparrow regret that unpublished letters cannot be answered individually.

Responses to questions are not intended to constitute or to take the place of medical or psychiatric evaluation, diagnosis or treatment. If you have a question about your child's health or well-being, consult your child's health-care provider. © T. Berry Brazelton, M.D., and Joshua Sparrow, M.D. Distributed by New York Times Special Features