After my residency in internal medicine in Boston, our young family moved to Philadelphia, where I went to work as an instructor at Temple University's School of Medicine. I was so new at this that sometimes I wasn't quite sure who was the teacher and who was the student, and I loved every minute of it.

But all was not perfect.

Heading home after teaching with my preschooler in tow, we quickly realized we couldn't find a grocery or supermarket with the fresh fruit, produce and other healthy foods we were accustomed to eating.

How could this be? The answer was out on the street itself.

My office looked down on North Broad Street, a 13-mile arrow-straight boulevard laid out by William Penn himself. The street runs through the middle of some of the worst urban blight of any American city in the past 40 years.

Unseen beneath the boulevard, the SEPTA subway flows north like a tributary from Center City, ferrying to Temple thousands of commuter students who seldom witness what life is like on the streets surrounding their campus oasis.

What they would find is a neighborhood of about 20,000 people who are poor, mostly African-American and Hispanic, and chronically disadvantaged.¹

Lower North Philadelphia can be a menacing world for children. Too many kids hang out in front of abandoned or boarded-up buildings, vulnerable to gangs, gun violence and worse. For many, it's not safe to walk to school, walk to a community center or use the playground (if one exists).

Barely one-third of the workforce has jobs. Less than 30 percent graduate from high school. Most of the housing is old and decaying. Even today, some homes lack indoor plumbing and phones. A majority of residents are renters; less than half own cars.

The U.S. Census Bureau in 1995 first began measuring whether households have access to food. That's when nutrition experts began talking about “food security,” when families have enough food at all times for active, healthy living.²

In Lower North Philadelphia, however, the issue is “food insecurity.” That's jargon for what happens when people go hungry. Or can't always afford nutritious, healthy food.³ Or live where the only places to buy groceries are high-priced convenience stores stocked with everything that is bad for you and almost nothing that's good for you.

It's a national problem. The latest census data tell us that just over 15 percent of all households with children are food insecure.⁴ That's an alarming 12.4 million children.⁵

More than half of these families can't afford to feed their kids good meals balanced with fresh fruit and vegetables. And the great majority—81 percent—rely instead on high-calorie, energy-dense junk food,⁶ which means fatty foods loaded with refined grains and added sugars.⁷

Even today the only alternatives in that neighborhood are a handful of bodegas and corner stores where you can't buy an apple but you can wash down one ounce of Cheetos (10 grams of fat)⁸ with a 22-ounce Coca-Cola Classic Slurpee (330 calories + about 88 grams of carbohydrates).⁹

Three blocks off Temple's campus stands a shuttered supermarket flanked by a wig shop and Popeye's Chicken & Biscuits (1 spicy chicken breast + buttermilk biscuit = 770 calories for $2.99).¹⁰ It's a busy place. A recent survey found that compared with other areas of the city, residents of Lower North Philadelphia are about 33 percent more likely to eat fast food and local take-out because that's all there is and it's cheap. Not surprisingly, nearly 30 percent of the children over age 5 have medical or physical disabilities, many of them diet-related.¹¹

This is the great paradox of food insecurity in America. When there isn't enough good food available, low-income families and kids have to eat what is available—food that is low in nutrients, high in calories, and certain to make a hard life even worse. They don't call it “junk food” for nothing.

One of my colleagues visited the area last year and encountered a little girl in the third grade who had just discovered her first banana. Imagine, in modern-day America!

How this is about to change and what it means for the future of the health and health care of everyone in America, we'll get to shortly. But first, let's take a look at the big picture.

Coast to coast, the insidious spread of childhood obesity is the rule rather than the exception, even in the most food-secure corners of the country. City, suburbia, exurbia, rural countryside—no family or community is immune.

Just like the calm and silent water of the proverb, most of America didn't realize an epidemic was rising until the shape of kids, teens and adults everywhere was changing and, along with it, the health of our entire society.

Today more than 33 percent of all children and adolescents, and about 65 percent of all adults are overweight or obese.¹² That works out to nearly 13 million kids and teenagers and some 144 million men and women, more than half the population of the United States.¹³

Like anyone who travels, I see overweight and obese kids everywhere, from airport concourses to the schools, community centers, clinics and grantee sites that I visit. It is a common sight. Kids of all ages, huffing and puffing, unable to climb stairs, parked in front of video games and computer screens as they munch their way through mountains of fatty snacks and sip gallons of sugary drinks.

If you think kids look bigger, it's because they are. This past year more than 250,000 children under age 6 exceeded the weight standards for regular car seats and new “husky” car seats were being developed and marketed.

In 1963 an average weight 10-year-old girl weighed about 77 pounds; today she weighs about 88. The average weight for a 10-year-old boy back then was about 74 pounds; today he weighs about 85 pounds. And that's just the average.¹⁴

Remember when kids actually went outdoors and played? Traveling today, I drive past paved-over school playgrounds, barren of jungle gyms, swings, kids and laughter, eerie and empty relics of the good old days before so many schools abandoned recess. I watch kids at airport boarding gates, comforting themselves with junk food. And I make a promise to myself that we have to change all this.

It is an all-American crisis. The galloping prevalence of obesity cuts across all categories of age, gender, education, income, profession, locale, parentage, race and ethnicity.

The epidemic explodes when it collides with determinative social and economic facts of life that segregate America's “haves” from our “have-nots”—factors such as race and ethnicity, poverty, failing housing and failed education, and the geography of food quality and supply.

Among our children, the epidemic is particularly virulent and is redirecting the trajectories of millions of young lives away from hope and health and toward despair and disease.

By 2004 the accumulating evidence elevated our own foundation's awareness to Code Red. So, with TIME and ABC News, we convened a national summit on obesity at Williamsburg, Virginia.

Many of our high-profile allies in this struggle were there: David Satcher, former U.S. Surgeon General; Professor Kelly Brownell of Yale; Dr. Tim Johnson of ABC.

In words that haunt me still, Vice Admiral Richard Carmona, U.S. Surgeon General at the time, described the epidemic in the starkest of terms:

Fortunately, the public and our leaders are awakening to the danger. Through our philanthropy and the support of others, evidence of the epidemic's course and consequences has now reached a convincing weight and mass that can no longer be avoided or overlooked.

The public agrees. In a survey we sponsored last year with the Harvard School of Public Health, 92 percent of Americans said childhood obesity is a serious national problem.¹⁶

Unless we turn back the epidemic of obesity at its point of origin—among our children—our society will pay a terrible human and financial price for as far out into the future as we can see.

As a result, the United States is on the threshold of powerful and necessary social change propelled by our collective instinct to survive. This is not new to Americans. We've stood here before and we've changed before—and in ways that look like they will be sustained.

In 1965, 43 percent of us smoked cigarettes.¹⁷

Today only 20.9 percent of us light up.¹⁸

In 1982, drunk drivers killed about 22,000 people.

In 2005, the toll had fallen to just over 12,000.¹⁹

In 1983, only 24 percent of us used seatbelts.²⁰

Today 82 percent of us buckle up.²¹

These statistics tell a story of radical transformations in individual behavior that were impossible to achieve without simultaneous policy, social and cultural change. The lives saved are countless and the misery avoided is incalculable, all because the country chose to change to survive.

Now it is time to do it again, and the stakes are even higher.

When David Satcher was Surgeon General, he said, “Overweight and obesity may soon cause as much preventable disease and death as cigarette smoking.”²²

A controversial prophesy, certainly, but one America cannot afford to ignore. The growing body of evidence is too powerful. Accordingly, the Robert Wood Johnson Foundation is taking action.

We believe the significant threat calls for a substantial investment that will help set the national agenda for change and will provoke significant increases in other private and public investment.

We must be bold enough to expect permanent, sustainable results by 2015, with benefits to the population, health care and the economy extending deep into this century.

Our approach is direct, practical and strong:

• First, make the case—with solid research and objective evidence—for the problem, what works to roll it back and what doesn't. We will need as much effort on the community level as on the policy and industry level.
• Second, test and retest the best approaches, then widely install the most promising models as a firewall against the epidemic's further spread. A pile of bricks does not equal a wall. So, this will require that each of the most important approaches be integrated to have the full effect.
• Third, educate and motivate our leaders and invest in advocacy to foster change.

And build a resource base big enough to match the enormity of the problem. How will we know it is working? We'll know when the evidence tells us so.

Next to adequate and sustained funding for programs that work, it is evidence we need more than anything else, evidence that establishes:

• How to get kids to eat well and physically move more;
• What school and family actions work best;
• That industry's interest in healthier lifestyles and eating habits is sincere and produces innovations that work; and
• That government “gets it,” with realistic and responsive policies and budgets.

Our commitment is ambitious. With it comes risk and resistance. But it is a commitment the Robert Wood Johnson Foundation was invented to make. Our experience and the evidence command us to make it now.

As we progress, it is essential that we understand the epidemic itself and its effect on each of us and on all of us.