ideal weight : About the "Peoples Choice" Ideal Weight formula

The "Peoples Choice" formula for Ideal Weight was designed by Dr. SB Halls. Its origins and justification are described on this page. The formula tries to predict what other similar people would choose as their own ideal weight.
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The formula is partly based on the publication by Dr. D. Crawford and K. Campbell1, entitled "Lay definitions of ideal weight and overweight", from the International Journal of Obesity in 1999. That article published data from an Australian survey which asked people to describe their own perceptions of "ideal weight" and "overweight".

People were asked: " Ideally, how much would you like to weigh at the moment?"

The study found that peoples Age and current Weight, correlated with the weight they considered to be ideal. In other words, the heavier people currently are, the heavier they believe their ideal weight is. And older they are, the heavier they set their own ideal weight.

The data from the Crawford and Campbell study is shown in the charts below. The authors published their data in units of Body Mass Index ( BMI = kg/m2). Since BMI = weight (in kilograms) divided by height (in meters) squared , their use of BMI allows their data to be applicable to adults with a broad range of height stature.

In the "Age vs Ideal Body Mass Index" chart (above), notice that Men's mean ideal BMI has less slope than women. Age has little influence on Mens percieved ideal weight, but Age has more influence over how Women perceive their ideal weight.

The second data source for the Peoples Choice Ideal Weight formula, is from the NHANES III study3 which provided a very large dataset of the American population's height and weights. Correlating the two studies, mens Age does not appear to be an independent variable in how men describe their ideal weight, while mens current BMI strongly influences with their perceived ideal weight. In women, both Age and current weight independently influence their perceived ideal weight.

Using the published data from the Australian study and the more detailed data of Americans from the NHANES III study, Dr. SB Halls created a formula in February 2002, which uses a persons Age, Gender, Height and Current Weight, to predict the mean body weight that a similar average person would say they considered as their "Ideal". This formula calculates the "Peoples Choice ideal BMI" (in kg/m2), which can then be converted to an ideal body Weight (in kilograms), by multiplying by height (in meters) squared. Weight in kilograms can be converted to pounds by multiplying by 2.2046.

Men Ideal BMI = 0.5 * kg/m2 + 11.5

Women Ideal BMI = 0.4 * kg/m2 + 0.03*Age + 11

By Steven B. Halls, MD