First, a Little History
Weight has had both positive and negative connotations in societies worldwide.

Historians have found overweight related to fertility, particularly citing prehistoric Venuses, statues of obese female figures, as symbols of womanhood and fertility. Prior to the 20th century most traditional cultures associated fatness with prosperity and good health, largely because low weight signified malnutrition and wasting diseases such as turberculosis. The belief also prevailed in life insurance circles that weight above average represented a reserve that could be drawn upon in the event of disease, trauma or emergency.

Then between 1900 and 1920 this relationship began to disappear in Western countries by a report published in 1908 "The Influence of Overweight and Underweight on Vitality" by Brandreth Symonds, a leading figure in life insurance medicine. The report demonstrated statistically the relationship between weight and longevity and showed that overweight was a greater risk factor in reduced life span than underweight. The results were published in a table in 1942. And so began the height and weight charts and Ideal Body Weight (IBW).

Ideal Body Weight (IBW)
You probably have had the opportunity to look at an Ideal Body Weight (IBW) chart. For some it may be an unpleasant experience, for others it may be misleading. The IBW chart is based on mortality and not morbidity. In others words, IBW does not correlate weight to health or prevention of disease. Other criticisms of the IBW chart is that it does not allow for body composition, body type or genetics. Someone with large bones or with a high percentage of lean tissue (muscle) would appear to be overweight according to the chart. Trying to attain IBW may be an unrealistic and unnecessary goal for many. It may also lead to unnecessary or fad dieting to achieve this magical number on the chart. So why use IBW at all? IBW can be used to determine if you are underweight, which may be associated with poor health or disease (see Can You Be Too Thin?). The IBW is a place to start, but should not be considered the only number.

Body Mass Index (BMI), A Better Indicator
The emphasis changed toward healthy weight ranges for adult men and women of all ages with the published Dietary Guidelines for Americans, USDA/DHHS. Then in 1989 the National Research Council (NRC) published Diet and Health: Implications for Reducing Chronic Disease Risk, proposed ranges for Body Mass Index (BMI). The BMI is now used to help assess weight to health risks. BMI is a ratio between weight and height. It is a mathematical formula that correlates with body fat. The BMI is more generous than IBW.

How to Measure BMI
BMI is determined by calculating your weight in kilograms divided by your height in meters squared (BMI=kg/m2). But there is no need to crunch numbers here! Use FirstPath.com's BMI Calculator to find your BMI.

Exceptions to BMI
BMI is a better predictor of disease risk than ideal body weight (IBW). However, there are certain people who should not use BMI as the basis for estimating body fat content: competitive athletes and body builders, whose BMI is high due to a relatively larger amount of muscle, and women who are pregnant or lactating. The BMI is not intended for use in growing children or for frail and sedentary elderly individuals.

Why is BMI Important?
The health risks due to excess weight appear to be the same for older as for younger adults. A BMI of 25-29 is considered overweight, a BMI of 30 or higher is considered obese. According to the National Heart Lung and Blood Institute a BMI of 27 or higher may increase your risk of developing co-morbid conditions. These conditions include, but are not limited to:

• Hypertension (High Blood Pressure)
• Cardiovascular Disease
• Elevated Cholesterol and Triglyceride levels
• Adult-Onset Diabetes (Type II)
• Sleep Apnea
• Osteoarthritis
• Female Infertility
• Gastroesophageal reflux
• Urinary stress incontinence

Obesity and Co-morbidity
A co-morbidity is any condition associated with obesity that:

1. Usually worsens as the degree of obesity increases and
2. Often improves as obesity is successfully treated

Improving Your Health:
Recent statistics show that 33% of adult Americans have a BMI of 27 or higher, resulting in over 300,000 lives lost each year due to weight-related illnesses.

If you have a BMI over 27, prevention of further weight gain is important and weight reduction is desirable.

Weight reduction is an important way to reduce your BMI and improve your overall health. Even a modest 5% reduction from your current weight is beneficial to your health. For instance, a 5'5" female who weighs 166 pounds (BMI=27), can improve her health by losing as little as ten pounds, reducing her BMI to 26. Lasting weight management can best be achieved by a long-term program that includes increased physical activity, healthy eating, and behavior modification For more information see Tips for Achieving a Healthy Weight.

Can You Be Too Thin?
Being too thin may be the result of anorexia nervosa, other eating disorders, loss of appetite related to certain diseases or treatments (such as chemotherapy) and is linked to menstrual irregularity. Excessive thinness can put women at risk for osteoporosis and in both women and men at greater risk of early death.

Many people-especially women-are concerned about body weight, even when their weight is normal (within IBW range). Excessive concern or obsession about weight may cause or lead to unhealthy behaviors such as excessive dieting or exercise, self-induced vomiting, and the abuse of laxatives or other medications. These practices can cause serious health problems.

If you lose weight suddenly or for unknown reasons, see a physician. Unexplained weight loss may be an early clue to a health problem.

Are You An Apple of A Pear?
Research suggests that the location of body fat also is an important factor in health risks for adults. Excess fat in the stomach area (apple shape) is a greater health risk than excess fat in the hips and thighs (pear shape). The easiest way to check your body fat distribution is to measure around your waistline with a tape measure and compare this with the measure around your hips or buttocks to see if your abdomen is larger. If your waist is larger, you are an apple. If your hips and buttocks are larger, you are a pear. If measurements are equal, you are a box.

The Problem with Being an Apple
Extra fat in the abdomen is linked to high blood pressure, diabetes, early heart disease, and certain types of cancer. Smoking and too much alcohol increase abdominal fat and the risk for diseases related to obesity. To reduce abdominal fat and decrease the risk for these diseases, incorporate daily exercise and lose excess body fat. For more information see Tips for Achieving a Healthy Weight.

References:

• Dalton .S., Overweight and Weight Management, The Health Professional's Guide to Understanding and Practice, 1997
• Blackburn, G. Effect of degree of weight loss on health benefits. Obes Res., 1995
• Kuczmarski, Flegal, Campbell, Johnson, Increasing prevalence of overweight among US adults: the National Health and Nutrition Examination Surveys, JAMA, 1994
  

Resources:

• National Heart Lung and Blood Institute