Most Americans are happily overweight but refuse to admit it, hardly trying to shed flab, a new study has claimed.

Americans carefully avoid counting the calories they consume over thanksgiving, a Gallup poll has found, adding their waistlines have increased and so has their perceptions of ideal weight.

Researchers found that men's average ideal weight is up 6.3 kg since Gallup first measured it in 1990, and their average actual weight is up 7.2 kg, the 'Discovery News' reported.

According to the poll, women's average ideal weight is up 5 kg since 1990, and their average actual weight is up 6.3 kg.

Over the past two decades people have consistently said they wanted to lose about 4.5 to 6.8 kg off their current weight to achieve their ideal weight.

About one-third of men say they are at or below their ideal weight, and about one-quarter of women say they are at or below their ideal weight, the poll found.

The idea that most Americans (and especially women) are in a constant struggle to lose weight is a myth. Only one-quarter of respondents say they are seriously trying to lose weight, which as Gallup notes "is much lower than the percentage who are above their ideal weight or say they would like to lose weight.

"Why aren't more people trying to lose weight? The answer is simple: because - despite two-thirds of Americans being overweight or obese - The majority of Americans say their weight is 'about right,' as they have typically responded over the past 20 years.

"But the 60 per cent who describe themselves as 'about right' is the highest Gallup has ever found," The Gallup report said, referring to this paradox as "weight denial".

It's important to note that the subjects' weight in this study were self-reported, and not verified by a doctor or scale. This may be a problem because people often lie about their weight, or simply don't know it.

According to a 2010 research study, nearly 40 per cent of overweight women believe themselves to be thinner than they really are, the report said.

That study also found that, contrary to most women thinking they are too fat, only 16 per cent of normal-weight women in the study perceived themselves as overweight.