More than three-quarters of obese Americans say they have healthy eating habits, according to a survey of more than 11,000 people.

About 40 percent of obese people also said they do ?vigorous? exercise at least three times a week, the telephone survey found.

?There is, perhaps, some denial going on. Or there is a lack of understanding of what does it mean to be eating healthy, and what is vigorous exercise,? said Dr. David Schutt of Thomson Medstat, the Michigan-based health-care research firm that conducted the survey.

The survey also found that 28 percent of obese people reported snacking two or more times a day, only slightly more than 24 percent of normal weight people who said they did. But the survey failed to ask people what ? and how much ? they ate, noted Dr. Jeffrey Koplan of Atlanta?s Emory University.

?The questions leave out quantity,? said Koplan, who chairs an Institute of Medicine committee on progress in preventing childhood obesity. Roughly two-thirds of Americans are overweight or heavier, and nearly one-third qualify as obese, according to the US Centers for Disease Control and Prevention.

Respondents to the survey were contacted through computer random digit dialing.