How To Calculate Your BMI - Body Fat
There is a rough measurement you can use without equipment to find the general body-weight levels that will be likely to limit you to a healthy level of body fat. With this method, which is their personal variation on what is known in exercise physiology as the Mahoney Formula, the calculation is slightly different from women and men.
Note: When you do your calculations, you will come up with two numbers, which represent a range corresponds to a healthy range of body fat. Therefore, if your real weight falls within the range of these numbers, your body fat will fall within the healthy range. (These formulas are derived from studies of normal adult body types. Growing adolescents, highly conditioned competitive athletes, and others with a high proportion of bone or muscle mass may actually have a low percentage of body fat, even though they are relatively heavy.)
The BMI Calculator Formula For Women
To find a body weight containing the healthy range of 18 to 22 percent body fat:
Here’s how this formula would work: if you are a women who is five feet three inches in height: First, you find your height in inches, which would be 63 inches. Then, you multiply that by 3.5 to get 220.5. Next, you subtract 108 from 220.5 to get 112.5-or the number of pounds that represents about 18 percent body fat for you.
Now, you multiply 112.5 tomes 0.10, a calculation that gives you 11.25, Finally, add 11.25 to 112.5 and you’ll get approximately 124 pounds-or the upper range of body weight that represents about 18 percent body fat for you.
Now, you multiply 112.5 times 0.10, a calculation that gives you 11.25. Finally, add 11.25 to 112.5, and you’ll get approximately 124 pounds-or the upper range of body weight that represents about 22 percent body fat.
So your desired body weight range for a healthy percent of body fat (18 to 22 percent) is 112.5 to 124 pounds.
What if your actual weight is above 124, to 22 percent body fat? You probably need to lose weight. Consult your physician.
What if your actual weight is below 112.5, or 18 percent body fat? That’s most likely all right….and may be expected if you are particularly athletic or have a naturally low- fat body type.
But generally, for optimum health, a woman’s body- fat percentage should be above about 12 percent of total body weight-for several reasons. Women, even more than men, must guard against losing too much body fat. For one thing, premenopausal women who are too thin may upset their hormonal balance by producing too little estrogen-and as a result experience amenorrhea, or the loss of at least three periods in a row.
Second, a women with too little body fat will be at a higher risk for osteoporosis, or thinning of the bones, which leads to a spontaneous fractures.
Also, a rapid weight loss may indicate another serious health problem, such as gastrointestinal problems or cancer.
Finally, excessively low weight may signal an eating disorder.
The BMI Calculator Formula For Men
To find a body weight containing the healthy range of 15 to 19 percent body fat:
So if you’re a man who is five feet ten, your height in inches is 70. Multiply that 4 to get 280. Then substract 128, and you’ll end up with 152 pounds, or the weight that will give you 15 percent body fat.
Now multiply 152 by 10 percent (0.10), and you’ll get 15.2. Add that to 152 pounds, and you’ll have 167.2 pounds as the upper range of healthy body weight for you-a fingure that includes about 19 percent body fat.
In contrast to women, there is less concern for men whose body fat dips below the 15-to-19 percent range- especially those men who are competitive athletes. On the other hand, an unusual or rapid weight loss-or weight loss accompanied by a decline in muscle mass-can suggest health problems that should be evaluated by a physician.
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