We’re fat. Really fat. And it’s not just us—it’s our kids, too. Have you seen them? They’re enormous.

According to the mantra of obesity experts, however, it’s much like Robin Williams (correctly) told Matt Damon in Good Will Hunting: It’s not your fault.

No, it’s not your fault, it’s not our fault, it’s not their fault. Unless “they” are restaurateurs, in which case it is their fault. That’s especially true for chain restaurants—the ones selling McAnything, blooming onions, and the like. They’re killing us by the greasy mouthful.

And because it’s their fault, these restaurateurs, we must give them their due regulatory dickens. Help is here, America. Trans fat bans. Menu-labeling here, there, and everywhere. More help is on the way, too. Caffeine and sugar and salt be gone. It’s for the children.

In some alternate universe, one that actually assigns blame to deserving people, it might be your fault, not theirs. Maybe it is your fault your kids are fat, since you feed them. Maybe the food that parents supply to their kids—and demand restaurants feed their kids—is making the kids fat. Which means parents need to do a better job of making sure their own kids eat healthy, and get some exercise.

Wouldn’t that be a refreshing message?

Cornell University marketing professor Brian Wansink, who heads the school’s Food and Brand Lab and served in the George W. Bush administration as executive director of the USDA’s Center for Nutrition Policy and Promotion, is not in the blame business. He’s an Ig Nobel-winning researcher, author of 2006’s Mindless Eating, and has been called “one of the world's leading authorities on consumer behavior.” Though he doesn’t point fingers, Wansink’s latest data suggests that our national fixation on blaming the restaurant industry for childhood obesity is misguided.

That conclusion comes from “The Joy of Cooking Too Much,” a study co-authored by Wansink and published in the Annals of Internal Medicine. In carrying out his research, Wansink and co-author Collin Payne, assistant professor of marketing at New Mexico State University-Las Cruces, relied on the simple premise that people tend to eat about two out of every three meals at home.

To learn whether home cooking might be a chief culprit behind America’s portliness, Wansink and Payne pored over seven decades of The Joy of Cooking, one of America’s most popular and durable cookbooks. After identifying recipes for 18 foods that had appeared in each edition of the book, the authors examined the calorie counts and serving sizes for those food over the years.

“If you look at all the common recipes, their calories and serving sizes, there’s about a 43% increase,” Wansink told Reason. “About two-thirds can be attributed to ingredients—more butter, more sugar, more use of sauces, nuts, and raisins—but the other third can be attributed to increases in portion size.

“The same pie that was to be cut in eight pieces in 1937? The Joy of Cooking now recommends you cut it into 6 pieces.”

Sounds perfectly sensible. But aren’t cookbooks just responding to increased restaurant portion sizes, thus putting the blame back on restaurateurs? Not quite. “A lot of the increases in calorie and serving sizes we started seeing in cookbooks before we saw them in restaurants,” Wansink said. “Our penchant for larger servings started in the home and then moved to the restaurant.”

But how might Wansink’s argument go over with parents—and other food and nutrition experts? That his book Mindless Eating earned kudos from such divergent sources as John Stossel, who featured Wansink’s work on 20/20, and the holy trinity of unholy food nannies—Marion Nestle, Kelly Brownell, and the Center for Science in the Public Interest—showed reason for hope.

Last month Wansink sat on a panel on ways to raise a healthy eater

At the annual South Beach Wine & Food Festival in Miami Beach last month, Wansink sat on a panel entitled Beyond Chicken Nuggets: How to Raise a Healthy Eater. In addition to Wansink, the panel featured food celebrities Rachael Ray and Tom Colicchio, South Beach Diet inventor Dr. Arthur Agatston, cookbook author (and wife of comedian Jerry Seinfeld) Jessica Seinfeld, and moderator Tara Parker-Pope, wellness columnist for The New York Times.

On its face, a panel featuring a daytime talk-show host, high-end restaurateur and head judge on Bravo’s hit Top Chef, diet-book author, uber-rich foodie mom, and New York Times writer wouldn’t appear to pose any danger to the restaurants-make-us-fat myth. (This year’s panel at least had better myth-busting potential than last year’s, which featured celebrity chefs—and torrid food nannies—Jamie Oliver and Alice Waters.)

But the overwhelming message of the panel was that parents—not the government or restaurants—are ultimately responsible for what their kids eat.

“We have to take some responsibility for the foods we bring into the home,” said Parker-Pope.

Taking responsibility often means, in the context of home cooking and lunch-sack packing, a healthy serving of chicanery.

“I advocate lying to children,” Parker-Pope declared.

Lying might mean mixing whole-wheat pasta in with white-wheat pasta, declared the chipper Ray, in a husky Kathleen Turner voice.

But lying isn’t the only solution. Colicchio advocated cooking with kids, giving them a stake in the meal. And though Wansink has launched a new project that nudges children to make healthier lunchroom choices, he’s also a father of two daughters, ages 2 and 4, who openly feeds his kids an eclectic mix of foods: “They’re lovers of sushi, vegetables—especially broccoli—foie gras, Diet Coke (when they can steal a sip from me), and McDonald’s cheeseburgers and French fries.”

Regardless of whether kids love healthy foods or not, argued Colicchio, parents are the gatekeepers to a healthy diet, and must be firm with kids. “If some blob of a thing was sitting on the ground, and you saw your kid pick it up and go to eat it, you’d say, ‘No!’” Colicchio said. “And so it’s just a matter of thinking about what we’re eating and sometimes, just saying, ‘No. We’re not going to do that.’”

But Colicchio made it clear that this choice is the parent’s alone.

“There’s a big discussion in some circles, with the Obamas coming in, about getting the nation to eat better,” Colicchio said. “But we can’t have a bunch of elitist chefs getting preachy and telling the country what they should eat. Fast food is here to stay. But we’ve got to get fast food makers to understand that there’s healthy food out there, and the only way they’re going to survive is if they make healthy fast food.”

Still, fast food makers have tried time and again to offer healthier foods, with mostly dismal results. Remember the McVeggie Burger? Regional fast-food chains that boasted fewer calories and less fat, like O’Naturals in Boston, never saw their dreams of vast expansion realized. Why?

One reason is that building a better—or healthier—McNugget isn’t easy. Seinfeld, for one, must know this. Her deceptively delicious chicken nugget recipe—which features healthy ingredients like flaxseed and pureed broccoli—met withering parental criticism at one popular recipe website.

But what about those menu-labeling and trans fat bans? Aren’t those efforts making kids healthier? Again, Wansink says the data doesn’t support that conclusion. “They’ve either been ineffective or disturbingly counterproductive,” he says. “All the data we’ve seen about menu labeling doesn’t show a consistent answer at all.

“Trying to change capitalism is a lot of work,” he adds, “and it won’t work.”

Obesity lawsuits aren’t the answer either, says Wansink.

“If we believe it’s a restaurant that’s made our kids fat, we’re not going to change, because it’s their fault,” he says. “We’re not going to arrest the control we do have as parents. We have the perfect justification: it’s not our fault. That’s where it really becomes dangerous. These suits obscure the difference we can make in our own lives right now.”

That difference starts and ends with parents. If this panel’s all-star cast can agree that parents hold the key to their own kids’ healthy eating, then the debate over childhood obesity might just be entering a healthy new chapter.

Baylen Linnekin is a writer living in Washington, D.C. He blogs at Crispy on the Outside.