Here is an excerpt from the text verbatim:
Current weight guidelines can be too generous
In the USDA's 2000 dietary guidelines, for Americans, healthy weights are those corresponding to BMIs between 18.5 and 25. BMIs above 25 are clearly labeled as unhealthy, but the guidelines dodge the issue of setting a lower healthy limit by not putting any label on BMIs below 18.5.
In choosing these limits, the committee charged with setting the guidelines tried to balance scientific evidence with public policy and perception. That's a difficult job, because there is no simple breakpoint between healthy and unhealthy weights. Panel members agreed that the risk of heart disease, diabetes, and high blood pressure begins to climb at BMIs of 22 or so. But they didn't feel justified choosing such a low number as the cutoff between healthy and unhealthy weights, because doing so would have labeled the majority of the U.S. population as overweight. Instead, they chose a BMI of 25 as the upper bound of healthy weights, based on clear evidence that the risk of dying prematurely increases above that point. Thus almost everyone with a BMI over 25--except for extremely muscular body builders--would be healthier with a lower BMI, but many people with a BMI of 23-25 are not at their healthiest weight.
Another problem with defining a range of BMIs from 18.5 to 25 as healthy is that this "allows" you to gain a fair amount of weight and still stay in the healthy range. For example, a woman who is five feet six inches and weighs 130 pounds (BMI 21) could gain 25 pounds and still be in the healthy range (BMI 25), whereas this much added weight poses clear health risks.
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