The Sunday paper isn't the only game in town when it comes to printed grocery coupons: Some health insurers are sending discount mailers to consumers as an incentive to eat healthier.
By their measures, at least, there's some evidence that it's working. Among recipients of such mailings, purchases of healthy items (per USDA guidelines) grew 4.5 percent in 2012 to 43 percent of grocery spending, according to a white paper from Linkwell Health.
The firm creates healthy-eating content for more than 15 insurers, including Humana and several local Blue Cross Blue Shield providers. Shoppers' purchases of seafood rose 95 percent and vegetables, 15 percent. Processed meat consumption fell 44 percent, and sugar purchases, 50 percent.
"There's a high literacy rate of coupons," said Ben Gardner, founder of Linkwell Health. The deals provide an extra nudge to shoppers who want to—or have been told by a doctor they should—eat healthier foods.
Such coupons could help make a dent in health-conscious shoppers' tabs.
The healthiest diets cost about $1.50 more per day, according to a study released in December from the Harvard School of Public Health. In part, that's because shoppers are typically relying on just store sales for fresh fare such as produce and meats, said Teri Gault, founder of sale-tracking site The Grocery Game.
"It's tough to eat healthy—it really could cost more," she said. On packaged foods, it's easier to stack a combination of manufacturers' coupons and store sales and coupons.
In a study published this year in the Centers for Disease Control and Prevention's Preventing Chronic Disease, researchers found that only 3 percent of the 1,056 online supermarket coupons it tracked were for vegetables, 1 percent for unprocessed meats and less than 1 percent for fruit.
Manufacturers' coupons also offer slim pickings. In the last week of March, 2,395 coupons were available to consumers from sources including weekly mailers and digital sites, according to The Grocery Game. Of those, just seven were for organic products; five, gluten-free; and two, whole wheat.
But consumers should take some of insurers' coupons with a grain of salt. Linkwell reported a 197 percent increase in purchases of low-sodium and low-fat deli meats—incentivized with coupons. "If the coupons are driving a 'healthier' processed meat, a 'healthier' less-processed snack food, I'd be concerned about that," said Dr. Davis Liu, author of "The Thrifty Patient." "It's still processed meat."
Nor are coupons smart savings if they get you to buy items you otherwise wouldn't, or that may be less healthy than your usual fare, Liu said.
"In general what's healthier is more fruits and vegetables, less meat and smaller portions," he said. "Just because it's cheaper, that doesn't mean you should buy it, or buy more of it."
In a few cases, insurers' definition of healthy is further astray. Last year, one Anthem Blue Cross Blue Shield policyholder showed the website Consumerist a "healthy savings" mailer he'd received that included coupons for mayonnaise, ice cream and pasta.
An Anthem Blue Cross Blue Shield spokeswoman said its program has been revamped with the insurer's partnership with Linkwell and the introduction of the program to more states. "We've actually discontinued those categories to avoid any confusion," she said.
Linkwell's Gardner said the company limits its coupon offerings to foods that pass USDA filters on salt, sugar and fat content, among other qualifiers, while encouraging small shifts in shopping habits.
"If we continue just to tell people that half of their plate should be fruits or vegetables, you're really shutting down the channel of communication," Gardner said. A waistline-conscious frozen dinner may fall short compared with a nutritious home-cooked dinner, but it's a better choice for shoppers who would otherwise buy a frozen meal that's high in calories, salt and fat, he said.
"We're not saying we've got this nirvana approach," he said. "But it's a step."
—By CNBC's Kelli B. Grant.