Eating disorders are about 10 times as common in women as in men. Anorexia, in which people starve themselves to control weight, leads to death in one in 10 cases, killing approximately 1,000 adolescent girls in the United States every year. Cassie’s healthy outlook is no accident. She has a terrific role model in her mom. Lisa Harwood, a marketing executive, runs her own business, Kicks for Kids, which introduces soccer programs to schools and youth groups. Though Lisa watches her weight, the word “diet” is a no-no in her home. Instead, she tries to keep the family eating basic, healthy food. A former school athlete, Lisa works out every day, and she is big on activities like biking and volleyball that the family can do together. Her favorite jogging partner is Cassie. “It’s important that she sees me doing these things,” says Lisa, 41. “It’s establishing a way of life.”

And it will pay dividends for years to come. For many women the commitment to healthy living comes after an adult health scare. But the seeds of health are planted in girlhood, when the body develops the strength to fight off disease. The flip side of this is that missing out on key nutrients and physical conditioning during childhood and adolescence lays the groundwork for trouble down the road. With women’s rates of osteoporosis, heart disease and cancer all rising, experts are working to reverse the trends for today’s girls. The message to mothers and daughters: for good health, start early and start right.

To get off on the right foot, pour your daughter a glass of milk. In addition to containing important nutrients like magnesium, vitamin D and potassium, milk is loaded with calcium, crucial to the prevention of osteoporosis. This crippling disease, which afflicts some 8 million American women, results from a loss of bone mass, usually after menopause. In fact, a woman’s chances of breaking her hip at the age of 80 are greatly influenced by the strength of her bones at 18. “It’s a pediatric disease with geriatric consequences,” says Dr. Duane Alexander, director of the National Institute of Child Health and Human Development. That’s because nearly 90 percent of adult skeletal mass is formed by the end of the teen growth spurt. Once peak mass is reached, between the ages of 20 and 30, a woman can work to maintain what she has. But she can’t add more.

It’s a message that millions of women and girls aren’t heeding. Studies show that 85 percent of adolescent girls do not get the four to five daily glasses of milk (or their equivalent in other calcium-rich foods like green leafy vegetables, tofu and sardines) needed to build optimal bone mass. Many girls stop drinking milk because they think it’s fattening (eight ounces of low-fat or skim milk have only 100 calories or so). They also stop exercising–the other prescription for healthy bones. Until they’re 9 or so, girls are as physically strong and confident as boys. But when puberty sets in, the nimble bodies that so easily climbed trees and swung from ropes start developing strange curves, and hormonal surges unleash aches and mood swings that seem impossible to understand or control. The result: girls begin to concentrate more on how they look than on how they feel.

The health consequences can be serious. Many adolescent girls develop negative habits like physical inactivity and destructive eating patterns: only two thirds of high-school girls exercise the recommended three times a week. More than half diet frequently; nearly 20 percent binge and purge. Yet girls who are physically active and have a good self-image are more likely to spurn dangerous habits like smoking, drinking, drug use and risky sexual behavior.

So what’s the best way to get young women through this crisis of confidence with their health intact? Moving the emphasis from thinness to fitness is key. In her book “The Body Project: An Intimate History of American Girls,” Joan Jacobs Brumberg writes that societal messages about beauty force girls to turn their bodies into a full-time project at the expense of their well-being. One way to fight this pull is through sports and the arts. If girls run from softball practice to guitar lessons, they have less time to obsess over their looks. And girls who play competitive sports or participate in activities like music have greater self-confidence, which translates into better health and overall achievement.

It worked for Dr. Renee Jenkins. As head of the department of pediatrics and child health at Howard University Hospital in Washington, D.C., Jenkins had confronted just about all of the problems girls struggle with. She enrolled her daughter Kristinza in violin lessons at 6 and tennis lessons at 9. By high school, Kris was performing with the D.C. Youth Orchestra and playing in tennis tournaments. “It gave me something to excel at,” says Kris, now 18. “It made me feel good about myself.”

It is never too early to set positive examples. For instance, if you tell your daughter to eat an apple instead of potato chips because the chips will make her fat, you’re sending one message. If you encourage her to eat broccoli by telling her it will give her more energy and strength for her soccer match, you’re sending another. And practice what you preach. An 8-year-old who sees her mother skipping meals and then bingeing is more likely to develop destructive eating patterns. Likewise, a girl who sees her mother walk, bike and enjoy physical activity is more likely to enjoy it herself.

In fact, mothers start shaping the health of their daughters before they are born. In his new book “Life in the Womb,” fetal physiologist Peter Nathanielsz of Cornell University concludes that the likelihood of developing diseases like diabetes, heart disease and obesity is programmed during pregnancy. “We’ve been sold a bill of goods that everything wrong with us is in our genes,” he says. “But the environment in the womb is just as important, if not more so, in determining who we are.” An expectant mother who eats well, exercises and avoids excessive stress may actually reduce her child’s risk of high blood pressure or cholesterol in old age.

That’s because fetuses pick up messages about their environment and adapt accordingly. Fetuses deprived of oxygen and adequate nutrients, for instance, adapt their blood flow, sending more blood to crucial organs like the brain and less to areas like the abdomen. The result, says Nathanielsz, is babies with larger heads and comparatively smaller abdominal organs like the liver and pancreas. For most of a person’s life that’s no big deal. But there may be a price to pay in old age. Babies born with disproportionately small abdomens have a greater tendency toward high cholesterol, high blood pressure and diabetes after 50.

This “prebirth programming” may also influence the likelihood of obesity. Paradoxically enough, it starts with too little food in the womb. When a pregnant woman does not get adequate calories and nutrients, her fetus adapts, adjusting its physiology to make the most of every calorie, and even to hoard every spare calorie as body fat. If that child is born into an environment where food is readily available, he or she is more likely to become obese than the child who got enough good food in the womb.

Does all of this mean that if you binged on french fries during pregnancy, your daughter is doomed to poor health? Absolutely not. The risk for disease may be reduced or even eliminated with healthy new habits. So even if your mother passed her weight problem and high blood pressure on to you, you can change the habits of your daughter and positively affect the health of her future daughters.

That’s what Mary Kimm is counting on. At 44, she has struggled with a weight problem all her life. For years she went on and off fad diets. Three years ago her daughter Emma’s weight started to balloon. Just 8, Emma was teased mercilessly by kids at school. She regularly came home in tears. “Having a daughter struggling with the same issues I had made a huge difference in my level of commitment,” says Kimm, editor in chief of a Virginia-based chain of newspapers. Last year, with the help of a physician, Mary and Emma overhauled their lifestyle. They adopted a balanced, low-fat eating plan and started exercising daily. Since then they’ve lost a total of 60 pounds, and they are training to run a 5K race together this summer.

That doesn’t mean it’s easy. There are plenty of days, says Emma, when she’d like to ditch the treadmill altogether and just veg out in front of the television with a soda and cookies. Making a long-term commitment to eating right and exercising is tough stuff at 11. “It’s probably something I’m going to be stuck with for the rest of my life,” says the sixth grader. Sure, it sounds like a raw deal now. But in 50 years, Emma will be telling her granddaughter it was worth it.