When it comes to living lean, sometimes it seems as though Americans just can't get it right.
That's the message from an Ipsos-Insight poll earlier this year that found that while 76 percent of consumers say they have healthy eating habits, 57 percent still consider themselves overweight.
So are tofu and celery more fattening than people thought, or do Americans just not get the healthy living equation?
Not surprisingly, experts say the disparity is due more to the diners than the dinners.
Ruth Kava of the American Council of Science and Health said recently that data such as these indicate that despite a flood of nutrition advice, people may actually understand very little about healthy eating.
She has no doubt people believe they are eating good diets, but said the reality probably is quite different, in part because many people confuse eating healthy foods with having an overall healthy diet.
"People say they have a healthy diet, but what does that mean to them?" Kava said. "Does it mean they eat an apple a day and the rest of the day eat burgers and french fries?"
The poll of 3,934 adults found that 87 percent of those surveyed said they eat healthy meals at least half the time. Eleven percent said they eat them always or almost always, while 12 percent said they rarely do.
What do people think a healthy diet is? Fifty-two percent said it is eating in moderation, while 51 percent said it was following the U.S. Food Guide Pyramid, which recommends a diet based on grains, lean meats and fresh produce.
Those answers may sound healthy, but experts say they are vague enough to leave plenty of room for weight gain.
Even those who eat healthy half or even most of the time probably aren't doing enough. Weight control is more nuanced than most people think, and eating healthy foods is not sufficient, said Richard Mattes, a nutrition professor at Purdue University.
Just a dozen or so extra calories a day — even from the healthiest foods — can cause a slow weight gain over the years.
People who eat so-called healthy diets but also are overweight probably are not active enough, Mattes said. As society has become more sedentary, it has become increasingly difficult to burn off those extra 12 calories.
But that's good news for the roughly two-thirds of Americans who are overweight or obese.
"The resolution doesn't require radical changes in diet or lifestyle," Mattes said. "The issue is to make small adjustments but to recognize that it will take some time for that weight to come off."
Of course, the collective American girth is not the only thing that's growing. Portion sizes have increased markedly in recent years, making it easier to add those dozen — or more likely a dozen dozen — daily calories.
Warren Belasco, an American studies professor who specializes in the sociology of food at the University of Maryland, said there also is a good chance people are not entirely truthful about their eating habits.
He said the data may better reflect what people want than what they do.
"That's generally the problem with figuring out how people eat. They generally cater to what the interviewer wants to hear," he said. "It's very hard to get around that."
The poll, which was conducted March 26-30 for Deloitte's Consumer Business Practice, has a margin of error of plus or minus 1.5 percentage points.