However, muscle is about 18 percent more dense than fat, so this is clearly not true. One problem with BMI is that it does not distinguish between muscle and fat.Ĭonsider that a person who does no exercise is 1.83 m, or 6 feet, tall and weighs 92 kg, or 203 pounds (lb), would have a BMI of 27.Īn Olympic athlete who is 1.83 m, or 6 feet, tall and weighs 96 kg, or 211 lb, would have a BMI of 28.Īccording to this, the athlete is more “overweight” than the person who does no exercise. However, he believes this new calculation gives a closer approximation to the reality of human shape and size. Humans are too complex to be described by a single figure. Trefethen points out that any calculation that assigns one number to a person will not be perfect. divides the weight by height to the power of 2.5, instead of 2, or squaredīMI (metric) = 1.3 x weight (kg) / height (m) 2.5īMI (imperial) = 5,734 x weight (lb) / height (in) 2.5.

multiplies the weight by 1.3 for metric measures (kg), or by 5,734 for imperial measures (lb).He recommends a “new BMI calculator” that: The result is that short people think they are thinner than they really are, while tall people think they are fatter than they are. The height term, he says, divides the weight by too much when people are short and by too little when they are tall. Trefethen argued that the formula leads to confusion and misinformation. In 2013, Nick Trefethen, a mathematician from Oxford University in the United Kingdom, wrote a letter to The Economist in which he questioned the usefulness of the current BMI formula, calling it a “bizarre measure.” After all, people are three-dimensional, not two-dimensional, and healthy bodies grow in different shapes and sizes. Now, some people argue, we have technology that can help us add some complexity to the calculation.

Surgery may also be a treatment option but is not available for everyone.When Quetelet devised the BMI formula, there were no computers, calculators, or electronic devices, so he developed a simple system. The Food and Drug Administration (FDA) has also approved medicines and other treatments for weight loss. Lifestyle changes that can reduce weight include following a heart-healthy eating plan lower in calories and unhealthy saturated fats and increasing physical activity. Talk to your provider before you consider stopping any medicine you are taking for another condition that you think is also impacting your weight. Some people find that their weight goes up when they start taking medicine for another health condition such as diabetes, depression, or high blood pressure. Unhealthy lifestyle habits, such as not getting enough physical activity and eating high-calorie, low-nutrient foods and beverages, can raise your risk of overweight and obesity. Your provider may talk to you about overweight and obesity if your BMI shows that your weight is above average for your height. BMI is a measure of body fat based on height and weight and is defined as the body mass (in kilograms) divided by the square of the body height (in meters) and expressed in units of kg/m². Healthcare providers use body mass index (BMI) to screen for overweight and obesity in adults.

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