Despite all the chatter about how to lose weight, few talk about how much should be lost. If you are overweight, deciding how much weight you should lose is not as simple as it seems at first blush. I rarely have to tell a patient she’s overweight. She knows it and has an intuitive sense of whether it’s mild, moderate, or severe in degree. She’s much less clear about how much weight she should lose. If it’s any consolation, clinicians in the field aren’t always sure either. Five weight standards have been in common usage over the last quarter-century:
Metropolitan Life Insurance Company Height and Weight Tables from 1983
Aesthetic Ideal Weights
USDA/HHS Healthy Weights
Body Mass Index.
The Metropolitan Life Insurance Company Weight Tables list desirable or ideal weights that were felt at one time to be associated with maximum longevity. We know now that populations can be a bit heavier than the Metropolitan weights without impairment of health or longevity. The tables were controversial right out of the gate and are little used now; I mention them for historical interest. Aesthetic Ideal Weights are somewhat personal, although clearly influenced by culture. You know without much thought at what weight you look your best. Whether others agree with you, and whether you could realistically hope to reach that weight, are entirely different matters. If your personal Aesthetic Ideal Weight matches the Hollywood hunk or sex kitten actress du jour, prepare for failure. Thespians and models want to be thin because the camera puts weight on them. Many of our beloved photogenic celebrities workout three hours daily with a personaal trainer. And on top of that , many visit plastic surgeons. I suggest you find a friend with your type of body frame and height who looks “normal” and healthy to you. What does he or she weigh? I also suggest validation of your Aesthetic Ideal Weight by a trusted adviser. Now you’ve got something to shoot for. In 1995, the U.S. Department of Agriculture and U.S. Department of Health and Human Services issued a chart of Suggested Healthy Weight ranges. By the turn of the century, the USDA/HHS’s Dietary Guidelines for Americans had abandoned the Healthy Weight table, recommending the use of BMI instead. A Realistic Weight goal is one that you have a reasonable expectation of achieving, accompanied by significant psychological or medical benefits. This standard is flexible. There is no weight chart to consult since your potential psychological or medical benefits are unique. These weights tend to be higher than the other benchmarks thus far reviewed. The Realistic Weight concept accepts that you can feel better, look better, and have fewer medical problems while falling far short of the recommended “healthy” body mass index (BMI, discussed later). Many of the illnesses caused or aggravated by overweight are improved significantly by loss of only 5 or 10 percent of body weight. The concept admits the the body cannot always be shaped at will: much of your shape and fat distribution are genetically determined. If all your blood relatives, have big buttocks, thighs, and legs, you will also, although you do have control over degree. For many people, the Realistic Weight concept is helpful and valid, and prevents the discouragement felt when performance falls short of ideal. Let’s not allow the perfect to be the enemy of the good. It’s not realistic to expect a 40-year-old mother of three to weigh the same as a 17-year-old girl with no kids. Body Mass Index (BMI) is your weight in kilograms divided by your height in meters squared (kg/m2). To determine your BMI but skip the math, use an online calculator. From a health standpoint, BMIs between 18.5 and 24.9 are the best for people under 65–75 years old. About a third of the United States population is at this healthy weight. If you are 5-feet, 3-inches tall, your maximum healthy weight is 140 pounds (BMI 24.9). If you are 5-feet, 9-inches tall, your maximum healthy weight is 169 pounds (BMI 24.9).
BMIs between 25 and 29.9 designate “overweight” and accurately describe about 35 percent of the U.S. population. A BMI of 30 or higher defines “obesity” and indicates high risk for poor health. About 30 percent of us are obese. At a BMI of 35 and above, the incidence of death and disease increases sharply. The BMI concept is helpful to researchers and obesity clinicians, but the number doesn’t mean much yet to the average person on the street, nor to many physicians. It should be used more widely. Know your BMI. If it is under 25, any excess fat you carry is unlikely to affect your health and longevity; your efforts to lose weight would be purely cosmetic. If we look only at older Americans, over 65–75 years old, being overweight, but not obese, seems to prolong life on average. Longest life spans are seen in these older people with a body mass index between 25 and 30. Disability rates are lowest for older Americans with a BMI around 24. So, if you are over 65, you may have less disability at a body mass index of 24, but you may die slightly earlier that someone with a BMI in the overweight range. These numbers, of course, apply only to groups of people defined by BMI, not to individuals. So, how much weight should you lose?
As a medical man, I endorse the healthy BMI concept (BMI 18.5 to 24.9) while realizing you may have aesthetic reasons to shoot for the lower end of the range. If you have weight-related health issues, aim for a BMI of 18.5-24.9, with 25 to 30 as your fallback position. If you are over 65, consider a goal BMI between 25 and 30. It’s important to set a weight goal. If you don’t know where you’re going, you’ll never get there.
All matters regarding your health require supervision by a personal physician or other appropriate health professional familiar with your current health status. Always consult your personal physician before making any dietary or exercise changes.