Not many fat people seem to be aware that they are indeed fat say doctors, adding that most of their obese patients did not think that they were fat enough to be in trouble.

According to experts, misperception of weight was becoming a major barrier to weight loss - a serious problem in India which had seen a near 20 per cent rise in overweight population rates between 1998 and 2005.

A University of Illinois study by researchers who surveyed more than 3,500 college applicants found that over a third could not report their weight accurately and overweight and obese men were more likely to underestimate their weight than women.

In physical exams, the height, weight and body mass index (BMI) of 3,622 18- to 20-year-old applicants to the Mexican University were recorded wherein only 33.6 per cent were found to be overweight or obese, but only 16.9 per cent described themselves as being in those categories.

Women seemed to judge their weight better than men, with the gap between the former's perception and reality on their weight being smaller -- 27.8 per cent of women were actually overweight or obese, as against only 21.2 per cent that believed that they were.

According to Margarita Teran-Garcia, professor of food science at the Univesidad Autonoma de San Luis Potos in Mexico, the misperception was important because the first step in  dealing with a weight problem was knowing that you had one.

According to experts, the findings of the study had serious implications for India where currently, 1 in 5 men and over 1 in 6 women are overweight, with some urban areas, recording rates are as high as 40 per cent.

According to cardiologist Dr Ashok Seth, chairman of Escorts Heart Institute, who spoke to The Times of India, India's perception of well being unfortunately was associated with being overweight. "The paradox here is that fat people are considered healthy while thin people are considered weak in India. Most of my patients who lose weight after a heart attack come to me thinking they have become weak."

One's perception of being fat relates to whether people around you are health conscious or overweight. More overweight people don't think they are fat because everybody around are like them. Obesity is one of the most important reasons for heart attacks as excessive body mass index increases chances of coronary artery disease," he added.

A recent study also suggests that Indian women seemed to be getting fatter, even as men were doing better in controlling their weight. The number of obese women in India in 2008, was 8 million (body mass index of 30 kg/m2) as against 4.4 million men. A BMI Of 18.5 or less is considered underweight according to standard BMI calculators, while normal range is 18.6-24.9, and overweight is 25 to 29.9 while obesity is above 30. BMI or body mass index is the ratio of your height to weight.

Excess bodyweight is a risk factor for various health conditions including cardiovascular diseases, diabetes, cancers, arthritis, hypertension and musculo-skeletal disorders, and account for nearly 3 million deaths every year worldwide.