TAKOMA PARK, MD. -- Sometimes a simple idea makes so much sense, you have to wonder: Why didn't folks think of this sooner?

Here's an excellent example: Increase the value of federal nutrition benefits, such as food stamps, if families use the extra money to buy healthy options like fresh fruit and vegetables, especially at farmers' markets.

This is one of those rare public policies where everyone wins. No trade-offs or downsides. Families stretch their food budgets while improving their diets. Farmers sell more produce. Society benefits through reduced health care costs.

Oren Hesterman, president of the Fair Food Network in Michigan, wrote last year in The Hill newspaper: "Boosting the amount of fruits and vegetables consumed by vulnerable populations is critical. These are the very same people who are disproportionately likely to suffer from type-2 diabetes, hypertension and heart disease. And how is that treatment for those diseases paid for? Often with Medicaid or Medicare."

"We can quite literally pay the farmer now instead of the doctor later," he writes.

This is federalism at its best, with variations on the theme bubbling up in different localities. One of the pioneering projects started here in Takoma Park, a Washington suburb, when a man named John Hyde was selling baked goods at a farmers market in a wealthy neighborhood.

Just a few miles away lived a community of poor Hispanic immigrants, who seldom patronized his stand. So in 2007, Hyde created the Crossroads Farmers Market, located it closer to the low-income families, and raised $7,000 from the National Watermelon Promotion Board to subsidize their purchases.

It was a "total gamble ... a crazy radical idea," says Christie Balch, who now runs Crossroads. The Department of Agriculture called Hyde the day before the market opened and told him, "What you're doing is illegal."

Fortunately, Hyde had influential friends, including a senior official at the department, who called his bosses and said: "What do you think the Washington Post would have to say about your trying to prevent poor people from eating fresh fruits and vegetables?"

They backed down. Now, more than 500 markets in 30 states utilize some form of subsidy program. The systems differ a bit, but basically work this way: A shopper who qualifies for food stamps (officially called the Supplemental Nutrition Assistance Program, or SNAP) tells a clerk at the market how much she wants to use from her benefit account. Say it's $15. That amount is deducted from the shopper's SNAP card, and the clerk gives her coupons worth $30, which can be spent like cash.

"We don't have to buy the $1 bag of Cheetos. We can spend a little bit more on healthier things: fruits and veggies," Melissa Davis of Lehi, Utah, told a local Fox station.

Vicki Zilke, a farmer who sells her produce at a market in Ypsilanti, Michigan, told YES Magazine: "I make more money, I expand my business, and then I can hire more people. If I hire more people, I then improve the bottom line of my community. It's a ripple effect."

These are not just isolated anecdotes. The Union of Concerned Scientists and the Center for a Livable Future at Johns Hopkins published a joint report that concluded: "Incentives for fruit and vegetable consumption could reap enormous health and economic benefits over time."

There's one problem: Subsidies are expensive, and each market has to raise funds to finance the bonus coupons. Here at Crossroads, the annual $55,000 budget comes from a mix of private donors, foundations and local governments, but Balch expects that when fall comes, accounts will run low and subsidies will have to be trimmed.

Washington has finally woken up to the possibilities here. Last year's farm bill provided $100 million in seed money, and this spring, about one-third of that was dispensed to underwrite local experiments.

The Forsyth Farmers' Market in Savannah, Georgia won a grant to establish a "mobile market" that will deliver directly to low-income "food deserts" where fresh produce is hard to find. Greensboro, North Carolina will try out a "customer rewards program" that encourages repeat shoppers.

The Rhode Island Public Health Institute will start "nutrition education and cooking demonstrations." New Orleans will set up a subsidy system at Circle Foods, "a locally and minority-owned grocery store."

This is exactly what many voters want from government: efficient programs that leverage the energy and creativity of local initiatives.

This is beyond politics. This is about improving health, helping farmers and saving money -- all at the same time. Who can be against that?

By Steven and Cokie Roberts, NEA Columnists