Dear Doctor: My teenagers refuse to eat vegetables unless they're fried. Are they doomed to obesity and ill health?

Dear Reader: We wish we could reassure you and say it'll all be OK, but studies have long been clear on the matter. What your kids eat now will shape their health for years -- and maybe decades -- to come.

Poor eating habits have caused a spike in childhood obesity in the last few decades. Today, more than 17 percent of kids ages 2 to 17 qualify as obese. That's double what it was 20 years ago.

Being overweight has put young people at increased risk of all kinds of health problems and led to a sharp increase in the diagnosis of conditions such as diabetes, high blood pressure, elevated blood cholesterol, fatty liver, and even asthma and sleep disorders.

But before you confront your kids with a list of "don'ts," which teens are naturally primed to resist, be aware that the newest study on youth nutrition has some great news. It arms you with the information you need to right the nutritional course while encouraging your teens in a positive way.

Here's the gist: Young people who ate fruits, vegetables, lean proteins and whole grains, and who steered clear of sugar, red meat and processed foods, gained significantly less weight as they entered young adulthood.

The study, conducted by researchers at the University of Minnesota, followed the eating habits of 2,500 adolescents from the time they were 15 until they turned 25.

Researchers found that by eating well at age 15, young people developed the habit of good nutrition, and it carried on into their 20s and beyond.

The takeaway? You can guide your children to a more healthful adulthood by helping them establish good eating habits while they are in their teens.

Some strategies:

-- Stock the fridge with plenty of vegetables, fruits and whole-grain products.

-- Clear out the processed foods and the fatty, salty snacks.

-- Serve lean meats, poultry, fish, beans and legumes for protein.

-- Make sure that serving portions are a reasonable size.

-- Make the home a no-soda zone. This includes diet drinks.

-- Steer clear of sugar and sweets.

The goal is moderation, and your best chance at success is to get creative. Instead of being forbidden, let the fried foods your kids love become special-event treats. That way, they'll be less likely to feel deprived and sneak-eat. Cooking together -- scouting recipes, shopping, preparing the food and eating as a family -- can go a long way to cementing the new eating behavior.

Exercise makes a big difference, not just to teens but for adults as well. There's no better way than to lead by example. Start taking family hikes or bike rides. Pick out a local race to train for and set an in-family competition with personal goals and rewards.

If you market these changes as something that's fun for the kids and for yourself, you're far more likely to create healthy habits that will last for life.

(Eve Glazier, M.D., MBA, is an internist and assistant professor of medicine at UCLA Health. Elizabeth Ko, M.D., is an internist and primary care physician at UCLA Health.)

(Send your questions to askthedoctors@mednet.ucla.edu, or write: Ask the Doctors, c/o Media Relations, UCLA Health, 924 Westwood Blvd., Suite 350, Los Angeles, CA, 90095.)

Dear Doctor: Do I really need a yearly mammogram?

Dear Reader: This might be hard to accept, but if you're woman at low to average risk of breast cancer, you probably don't need a yearly mammogram. That's not to say we shouldn't give mammograms their due.

Mammograms can reduce deaths from breast cancer, and they're an important reason why breast cancer death rates have decreased over the last 40 years in this country. Studies have found a decreased death rate from breast cancer among women who have had mammograms compared to those who didn't.

Now let's look at just how much benefit. The public health advocacy group the U.S. Preventive Services Task Force calculated that, if 10,000 women between the ages of 39 and 49 had regular mammograms for 10 years, it would prevent three breast cancer deaths. For the same number of women between the ages of 50 and 59, there would be eight fewer breast cancer deaths. And for women between 60 and 69, there would be 21 fewer breast cancer deaths over that 10-year time period.

In short, the overall death rates were not significantly different between those women who had mammograms and those who didn't. This has especially been shown in studies in Canada and Sweden that compared the impact of annual mammograms with yearly breast exams from a health professional. In a 22-year Canadian study of 89,000 women, no difference in death rate was seen among women who had regular mammograms compared to those who had yearly breast exams with a health professional. This may point more to the importance of getting a yearly breast exam than the benefit of getting a mammogram.

Mammograms also have downsides. A primary one is that they have many false positives, leading to more imaging, breast biopsies and significant anxiety for patients. Another is that many breast cancers, such as ductal carcinoma in situ, would never be of clinical significance, so finding them on a mammogram is of little benefit.

That's not to say mammograms aren't useful. They do find breast cancers. But doctors and their patients need to discuss their risks and their benefits.

If you're a woman who has a mother or a sister with breast cancer, or if you have the BRCA1 or BRCA2 gene mutation that increases breast cancer risk, then a yearly mammogram after the age of 40 is a good idea. If you have a combination of risk factors -- such as having had your first baby after the age of 30, having later-onset menopause or having had an earlier onset of menstruation -- then a mammogram is likely a good idea.

However, if you're at average risk of breast cancer and between the ages of 40 and 49, there is only a small statistical benefit in having a mammogram, which should be balanced with the risks of testing.

If you are between the ages of 50 and 69, the benefit of a mammogram may overcome risk. At that age, you should get a mammogram every two years.

If you're older than 70, keep in mind that breast cancer rates increase up to the age of 80, so the screening could have a benefit. But that benefit must be weighed against the likelihood of dying from something else. Here again, the recommendation is for a mammogram every two years, but you should discuss your individual needs with your doctor.

Breast cancer screening is still evolving, with newer 3-D types of mammograms, breast MRIs and the possibility of biochemical markers to detect breast cancer. We'll need future studies of these technologies to assess their effectiveness at detecting breast cancer and reducing death rates. In time, the recommendations may change yet again.

(Robert Ashley, M.D., is an internist and assistant professor of medicine at the University of California, Los Angeles.)

(Send your questions to askthedoctors@mednet.ucla.edu, or write: Ask the Doctors, c/o Media Relations, UCLA Health, 924 Westwood Blvd., Suite 350, Los Angeles, CA, 90095.)

Dear Doctor: I'm going sailing with friends soon. Since I tend to get motion sickness in cars and airplanes, I'm worried that means I'll get seasick as well. Are there any natural remedies?

Dear Reader: If it helps at all, you're far from alone. A large portion of the population suffers some degree of motion sickness during travel. The most common effects -- dizziness, nausea, even vomiting -- are sure to ruin your day. For some people, additional symptoms like cold sweats, a throbbing headache or a bout of anxiety only deepen the misery.

The culprit in motion sickness is believed to be (scientists still aren't sure) the disconnect between what your eyes see and what the sensitive mechanism in your inner ear, which controls balance, feels.

When you walk or run or twist or bend down, those structures in your inner ear, known as the vestibular system, are in sync with what your eyes are telling you. You are moving, but the ground you stand on is not.

On a boat, however, your eyes and your inner ear are sending seriously mixed messages to your brain. Your eyes know you are sitting still, but according to your vestibular system, you're in motion. For reasons that are still unclear, it is this sensory disconnect that lights up pathways in the brain, causing the symptoms of motion sickness. And all you want is relief.

Some sufferers rely on antihistamines such as Dramamine, an over-the-counter medication, which can control nausea and vomiting. Prescription medications, including the Transderm Scop patch and promethazine, can also help with the symptoms of seasickness. But these medications can have side effects such as dry mouth or drowsiness.

Since you want to go the natural route, let's take a look at your options.

According to the Centers for Disease Control and Prevention, simple behaviors can give you a leg up. Stay hydrated, skip the beer and cocktails, don't drink any caffeine and limit eating to small meals. If possible, gaze out at a fixed point on the horizon. This lets your brain confirm the input that it's getting from your eyes and your inner ear -- yep, you're definitely in motion. (For people who tend to get carsick, riding in the front seat can help in the same way.)

As for natural remedies, a lot of travelers swear by ginger, which has been shown to ease nausea associated with motion sickness. You can find ginger in powdered form in many natural food stores and pharmacies. Dramamine also offers what it says is a clinically tested full dose of powdered ginger, packaged in a single capsule. Candied ginger and ginger tea are also options.

Although there is conflicting evidence over its effectiveness, acupressure has its proponents. In this method, constant pressure is applied to the insides of the wrists via special elastic wristbands.

When you do find an effective natural cure, there's a bonus. You're now prepared for the latest frontier in motion sickness -- virtual reality!

(Eve Glazier, M.D., MBA, is an internist and assistant professor of medicine at UCLA Health. Elizabeth Ko, M.D., is an internist and primary care physician at UCLA Health.)

(Send your questions to askthedoctors@mednet.ucla.edu, or write: Ask the Doctors, c/o Media Relations, UCLA Health, 924 Westwood Blvd., Suite 350, Los Angeles, CA, 90095.)