Cook from scratch. Eat foods in season. Buy locally. That is the conventional wisdom on what Americans must do to become healthier.

Ben Gardner disagrees. The founder of Linkwell Health knows that Americans, especially those with chronic diseases, should eat better. Consumers with diabetes buy twice as many candy bars and more than twice as much Mountain Dew as their healthy peers, according to the research firm Nielsen, while those with heart disease buy 10 times as many frozen dinners.

But instead of trying to persuade these customers to purchase fresh produce and prepare a home-cooked meal, Linkwell offers them coupons for more healthful frozen dinners or diet soda. In short, it doesn’t let the ideal be the enemy of better eating, and the strategy is working.

Gardner’s approach reflects his background, which is healthcare, not food. Health insurers had spent decades building sophisticated, and expensive, disease-management programs. And yet, given the skyrocketing rates of obesity and chronic disease in the United States, it was clear that they couldn’t compete with slick marketing campaigns for chips, candy, soda and other unhealthful foods. Why not, Gardner thought, steal a page from the food companies’ playbook to encourage more healthful eating?

“Instead of sending someone a 100-page booklet, which nobody reads, about how to manage your health, why not just give them a coupon that they can actually use?” he says.

Americans do love coupons. More than 80 percent say they use coupons regularly, according to NCH Marketing, which tracks usage. In 2011, fueled by tough economic times, we redeemed $4.6 billion worth of coupons, a 12 percent rise over the previous year. Most of those, a quick peek through the Sunday paper will prove, are for unhealthful foods: soda, chips and snack cakes.

Gardner’s task was to target the consumers who most need to change the way they eat. The answer was to utilize an innovative program implemented by — wait for it — the U.S. Postal Service. When you move and file an official Postal Service change-of-address form, you can elect to receive useful discounts on moving trucks, household appliances, furniture and storage. It’s what you need, when you need it. (Gardner worked for several years at Imagitas, the company that designed and manages the postal program.)

To target needy consumers, Gardner reached out to health insurers, which have detailed health data on patients who struggle with their weight and diseases. He asked them to include healthful food coupons in their regular mailings. To protect patients’ privacy, Linkwell never sees the health data nor do the brands that sponsor the coupons.

Over the past four years, Linkwell has partnered with 20 health plans, including EmblemHealth, Humana, United Healthcare and WellPoint, which cover 120 million consumers, mailing about 100 million coupons from well-known brands such as General Mills, Kellogg’s, Kraft and Quaker Oats. The take-up rate — the number of consumers who use the coupons they receive — is more than double that for coupons in the Sunday newspaper circulars.

Linkwell also has run pilot programs in which grocery stores offer discounts on fresh produce or seafood. It is experimenting with promotions in which customers who buy a box of, say, Special K get $1 off fresh blueberries.