What Is Considered a Slim Waist Size?

Waist sizes aren't as slim as they used to be. According to a survey conducted by SizeUK, the average British woman had a waist size of 27.4 inches, compared to a waist size of 34 inches in 2004. A similar survey by SizeUSA resulted in similar findings in American women. An expanding middle doesn't just mean you have problems finding accommodating clothes; larger waist sizes are associated with health conditions such as heart disease and diabetes.

BMI and Waist Size

Although the definition of a slim waist may be arbitrary, given your height and physique, one thing experts know is that superfluous abdominal fat may be a risk to your health 2. According to the Weight-control Information Network, or WIN, using your Body Mass Index, or BMI, in conjunction with your waist size can help you determine if you're overweight or obese. A BMI of 25. to 29.9. indicates that you may be overweight, while a BMI of 30 or more suggests obesity. However, the problem with BMI is that it doesn't necessarily tell you how your ratio of fat to lean muscle. For example, trained athletes can have a high BMI and still be perfectly fit.

Taking Measurements

How to Calculate BMI

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Even if your BMI is within normal, it's still a good idea to measure your waist, because it's still possible for you to carry too much fat in this area, says WIN. Adult females with a waist size of more than 35 inches and adult males with a waist size of more than 40 inches may have too much abdominal fat. Another way to make sure that your waist size suggests an even distribution of body fat is to look at your waist-to-hip ratio, or WHR. You can derive this number by dividing the circumference of your waist by that of your hips. Women and men with a WHR of more than 0.80 and 1.00, respectively, have apple shaped bodies -- an indicator of excess abdominal fat.

Waist Size Dangers

Results of the SizeUK survey indicate that only 8 percent of the female population have an hour-glass shape seen in classic movie stars such as Sophia Loren and Marilyn Monroe -- a nipped-in waist with curvy breasts and hips. However, aesthetics aside, a waist size that's disproportionately large can mean trouble on the health front. The deep visceral fat under your belly secretes hormones and chemicals almost like a gland, according to Harvard Medical School. One reason visceral fat can be so devastating is that the substances it releases find their way into the liver and may ultimately cause insulin resistance.

Trimming the Middle

Is There an Ideal Waist-to-Chest Ratio?

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According to a September 2004 BBC News report, the SizeUK and SizeUSA surveys were conducted to help manufacturers better design clothing that fits the average customer. However, if you don't want to fall into a demographic that features expanding waistlines, there's something you can do about it: exercise. According to Harvard Medical School, moderate to vigorous aerobic activity whittles your waist into shape. Aim to get 30 to 60 minutes of exercise each day.