It's no secret that the pounds creep up on you - it's not one or two huge meals that put on the pounds but instead the incremental, everyday diet and lifestyle choices.
On the other hand, most people also believe that with Americans so fixated on their weight, people (especially women) are painfully aware of every calorie they consume and each new ounce they gain - much like the Bridget Jones film and book character.
A new study suggests that for many women it's not true.
In a study published in the March issue of the Journal of Women's Health, University of Texas Medical Branch researchers found that a significant number of women evaluated at six-month intervals did not recognize recent gains in weight.
Researchers tracked 466 women of various ethnicities over 36 months and found that nearly one-third of women did not notice a weight gain of approximately 4.5 pounds over a six-month time, and one-quarter of women did not notice a weight gain of nearly 9 pounds over the same period.
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The study, which is believed to be the first to explore the accuracy of self-perception of recent weight gain, found that African-American women and women who used DMPA users (the birth control shot), were more likely than white or Hispanic women to notice their weight gain.
The new findings are in line with previous research.
In 2010, for example, a study found that nearly four in 10 overweight women believe themselves to be thinner than they really are. The study's authors surveyed 2,224 women between 18 and 25 years old from a variety of ethnicities.
Using the subjects' calculated Body Mass Index (BMI) and self perception of weight, the researchers found that 36.8 percent of the overweight women (and 10.5 percent of the obese women) believed themselves to be underweight, or of normal weight.
Though it's often assumed that most women think they are too fat, only 16 percent of normal-weight women in the study perceived themselves as overweight. The vast majority (84 percent) accurately perceived themselves as normal weight or underweight.
These findings concern researchers because if people don't realize they are overweight they won't make an effort to lose weight. These findings also have implications for the wider obesity epidemic, because doctors should not assume that their overweight or obese patients are aware of their weight gains (or even their absolute weight).