Ideal body weight (IBW) is a concept used in medicine, nutrition, and fitness to determine a healthy weight range for an individual based on factors such as height, gender, and body composition. Unlike actual body weight, which can be influenced by muscle mass, fat distribution, and bone density, IBW provides a reference point for assessing health risks and medical dosing. Understanding IBW is essential for managing obesity, malnutrition, and various chronic diseases.

Several methods have been developed to estimate ideal body weight, with the most commonly used formulas being the Devine formula, the Robinson formula, and the Miller formula. The Devine formula, originally designed for drug dosing, estimates IBW in men as 50 kg plus 2.3 kg for each inch over 5 feet and in women as 45.5 kg plus 2.3 kg for each inch over 5 feet. Other formulas provide slight variations, but all aim to establish a weight range that minimizes health risks 1–4.

Body Mass Index (BMI) is another widely used measure that classifies individuals into weight categories based on height and weight. Although not a direct measure of IBW, BMI helps determine if a person falls within an optimal weight range. However, it does not account for variations in muscle mass, making it less accurate for athletes and individuals with higher muscle density 5,6.

Ideal body weight plays a crucial role in medical and surgical settings. For instance, some anesthetic drug dosages rely on IBW rather than total body weight to prevent complications such as overdosing in obese patients. Additionally, IBW is used to assess nutritional status, guiding interventions for patients who are underweight or overweight.

In obesity management, ideal body weight serves as a target for weight loss goals, helping patients and healthcare providers develop realistic plans to reduce cardiovascular risks, diabetes, and other weight-related conditions. Conversely, in cases of malnutrition or eating disorders, IBW or the related concept of expected body weight is used to determine appropriate weight restoration targets 7–9.

Despite its usefulness, IBW has limitations. The standard formulas do not consider variations in muscle mass, bone density, or ethnic differences in body composition. For example, highly muscular individuals may have a weight above IBW but still be in excellent health. Similarly, older adults with significant muscle loss may fall within their IBW range but still be at risk for frailty-related conditions 8,10.

Newer methods, such as bioelectrical impedance analysis and dual-energy X-ray absorptiometry (DEXA), provide more precise assessments of body composition, offering a better understanding of an individual’s health status beyond IBW alone 11,12.

Ideal body weight remains a valuable tool in medical and nutritional sciences for assessing health risks and guiding treatment plans. While IBW formulas provide a useful reference, they should be used alongside other measures, such as BMI and body composition analysis, for a more comprehensive evaluation of an individual’s health. Advances in technology and research continue to refine our understanding of what constitutes a healthy weight, emphasizing the importance of personalized approaches to weight management.

References

1. Evidencio. Ideal body weight (Devine formula) – Evidencio. https://www.evidencio.com/models/show/430.
2. Evidencio. Ideal body weight (Miller formula) – Evidencio. https://evidencio.com/models/show/431.
3. Evidencio. Ideal body weight (Robinson formula) – Evidencio. https://www.evidencio.com/models/show/432.
4. Ideal Body Weight. https://www.cdc.gov/dengue/training/cme/ccm/page57681.html.
5. CDC. Adult BMI Calculator. BMI https://www.cdc.gov/bmi/adult-calculator/index.html (2024).
6. Calculate your body mass index (BMI) for adults – NHS. nhs.uk https://www.nhs.uk/health-assessment-tools/calculate-your-body-mass-index/calculate-bmi-for-adults (2023).
7. Sandowski, S. A. What is the ideal body weight? Family Practice 17, 348–351 (2000). DOI: 10.1093/fampra/17.4.348
8. Chichester, S., Holmes, T. M. & Hubbard, J. Ideal body weight: a commentary. Clin Nutr ESPEN 46, 246–250 (2021). DOI: 10.1016/j.clnesp.2021.09.746
9. Le Grange, D. et al. Calculation of Expected Body Weight in Adolescents With Eating Disorders. Pediatrics 129, e438–e446 (2012). DOI: 10.1542/peds.2011-1676
10. Knapp, T. R. A Methodological Critique of the ‘Ideal Weight’ Concept. JAMA 250, 506–510 (1983). DOI: 10.1001/jama.1983.03340040046030
11. Feng, Q. et al. Comparison of body composition measures assessed by bioelectrical impedance analysis versus dual-energy X-ray absorptiometry in the United Kingdom Biobank. Clinical Nutrition ESPEN 63, 214–225 (2024). DOI: 10.1016/j.clnesp.2024.06.040
12. Okasora, K. et al. Comparison of bioelectrical impedance analysis and dual energy X-ray absorptiometry for assessment of body composition in children. Pediatr Int 41, 121–125 (1999). DOI: 10.1046/j.1442-200x.1999.4121048.x