Q: What is the best method for determining an individual's ideal body weight?

A: To determine ideal body weight, individuals should not rely solely on a bathroom scale, height-weight tables, or percent body-fat measurements.

Sound nutrition and exercise science principles, along with common sense, mandate that individuals should avoid setting ''hard and fast'' body-weight goals. Rather, they should strive for achieving a level of body weight that is compatible with a healthy lifestyle (e.g., sensible eating, regular exercise, etc.).

All factors considered, the body weight that results from adopting such a lifestyle should ultimately be considered as the ideal union between an individual's wellness level, genetic potential, and a state of reality.

What represents a safe, realistic, and, perhaps more importantly, attainable body weight for an individual will depend (to a large extent) on the following factors:

• Medical history
  An individual's current medical history, to include a thoughtful review of personal health-risk factors, should be taken into account when attempting to define ideal body weight. For example, if an individual's blood pressure is elevated, a modest weight reduction (as little as 10 lbs.) has been shown to be quite beneficial.
  
  Extra body mass means that the heart must work harder to pump blood through miles of extra capillaries that feed that extra tissue. Type 2 diabetes and blood lipid-lipoprotein profiles are further examples of medical conditions that can be positively affected by weight loss.
  
  

• Family history
  Body weight, like most other physical characteristics, is strongly influenced by genetic factors. If an individual's parents and siblings are extremely overweight, it is highly unlikely that such an individual will ever be ''model-thin.'' As unfair as such a judgment might first appear, such a limitation should be kept in mind when establishing realistic body-weight goals.
  
  
• Body composition
  Leaner bodies are more effective calorie burners. The more muscle or lean body mass individuals have, the more calories they burn.
  
  Men naturally have more muscle mass than women, and, as a result, have higher metabolic rates. Furthermore, individuals who exercise on a regular basis tend to have more muscle mass and higher metabolic rates compared to their sedentary counterparts.
  
  Accordingly, although individuals who have a relatively high amount of muscle may weigh substantially more than others of similar heights, their body-weight levels may be entirely appropriate given their lean muscle mass.
  
  

• Body-fat distribution
  Body fat located in the upper-body region is very risky in terms of health profiles. If individuals possess a high amount of upper-body or abdominal fat, they should consider losing weight (specifically body fat) through a combined program of sensible eating and exercise.
  
  One commonly accepted method of determining whether individuals have excessive amounts of upper-body fat is to look at their waist-to-hip ratios. The waist-to-hip ratio (WHR) is a simple, yet accurate, method for determining body-fat distribution patterns.
  
  WHR is determined by dividing the waist circumference by the hip circumference. Waist circumference is defined as the smallest circumference between the rib cage and belly button. Hip circumference is defined as the largest circumference of the hip-buttocks region.
  
  Men with WHR values exceeding 0.95 are considered to have an excessive amount of upper-body fat, while those with less than 0.95 are deemed to have an acceptable level of upper-body fat. Women with WHR values above 0.86 are considered to have an unhealthy amount of upper-body fat, while those with scores less than 0.86 are designated as having a reasonable level of accumulated adipose tissue on their upper bodies.

• BMI (Quetelet’s Index) assesses weight relative to height. It is derived from body mass and stature to evaluate normalcy of one’s weight. While ideal for ranking and determining patterns of distribution, it is not valid for children, senior populations or hypertrophied populations groups (athletes)

• Functional ability
  If the ability to effectively and efficiently perform activities of daily living and to comfortably engage in a variety of recreational pursuits is inhibited, an individual should strive to attain a level of body weight that will support a healthy, functional lifestyle.