In a recent New England Journal of Medicine article, Danish researchers showed significant correlations between childhood obesity and coronary artery disease as adults. Looking at 276,835 children born between 1930 and 1976, a linear correlation was found with increasing BMI (Body Mass Index) directly related to increasing risk of having a heart attack. The example used was that a 13 year old boy who is 11kg (24.2 lbs) overweight will have a 33% higher likelihood of having a coronary event than a similar boy of average weight.
NIH statistics show that 17% 0f American children are obese, triple the number since 1980!
Smoking and obesity have become two of the major causes of morbidity and mortality in our country, both of which are preventable. Obesity is a multifactorial issue that stems primarily from the obvious - poor diet and lack of exercise. Granted, the "American diet" is horrendous overall, with plastic-wrapped, preserved offerings of fried this and that, breaded and cheese-filled whatevers, and heaping portions of processed carbohydrates. One of the problems is that these foods are being marketed to children. Sales and demographics experts run numbers to see how they can most effectively sell horrendously unhealthy foods to more and more children (don't you feel guilty, you heartless bastards?). Cartoons and plastic gifts are used to entice kids to throw fits until they get the Happy Meal or package of sweets that they saw on TV. Also, there is a trend in the media to say that "It's OK to be yourself (aka obese)." Yes, it is good to be comfortable with yourself as a person, but it is not OK to be morbidly obese! From a pure healthcare standpoint, once you are more than 10-20 lbs overweight, you should start looking at ways to lose some poundage, not find ways to justify your excess weight in the eyes of society. It's not insensitive or rude, it's your health. We have gotten so bad, that last year a physician in New Hampshire actually lost his license because one of his patients was offended that he told her that she was overweight and needed to lose weight for her health. She complained to the board and when he refused to go to sensitivity training, they took his license! This to me is absolutely ridiculous. It's like an alcoholic suing you because you told them to stop drinking!
It comes down to parents, however, to provide their children with a healthy diet and teach them lifelong lessons of nutrition and regular exercise. To do your child the most good, feed them locally grown, organic foods when possible, avoid prepackaged foods as much as you can, and avoid fast foods entirely. Minimal or no sodas/sport drinks/etc, water down your juices, and no bottled water (that's more of an environmental concern, though). Once the kids are out of the house, it's tough to encourage these things, so do it while you have their full attention. Also, don't forget the exercise! Limit TV/computer/video game time significantly. Go cycling or play ball with your kids, take them surfing or hiking instead of letting them vegetate in front of the television. Don't buy your child Guitar Hero, buy them an actual guitar! Fiddling with 4 buttons on a plastic guitar teaches them nothing except that it's OK to sit around on the couch and do nothing to better yourself in any way. Your son won't thank you for all the dates he DIDN'T get because you encouraged him to be an awesome "Guitar Hero." He may, on the other hand, thank you for the guitar lessons after the plethora of dates he actually got from his swoon-worthy real-life guitar melodies. Oh, and virtual dates don't count.
Baker JL et al. Childhood body-mass index and the risk of coronary heart disease in adulthood. N Engl J Med 2007 Dec 6; 357:2329.