BMI is only an indirect indicator of body fatness and therefore will not accurately classify all individuals, specifically because it fails to distinguish between

Question

BlackTom AI · Accepted Answer

BMI is calculated as weight (kg) divided by height (m) squared: BMI = weight / height^2. It is an indirect index of body fat because it uses total body mass without separating its components.

1. Relevant knowledge points and concepts
- Body mass has two principal components for this purpose: fat mass (adipose tissue) and fat-free mass (muscle, bone, organs, water).  
- BMI is a simple ratio that correlates with population-level body fat but cannot distinguish composition in an individual.  
- Body fat percentage and body composition measurements (e.g., DEXA, bioelectrical impedance) directly assess fat versus fat-free mass.

2. Step-by-step reasoning
- Since BMI uses only total weight and height, two people with identical height and weight will have the same BMI regardless of how their mass is partitioned.  
- Therefore BMI cannot tell whether a high weight is due to adipose tissue (fat) or to increased lean tissue (muscle, bone, water).

3. Example calculation with intermediate steps
- Person A (athlete): height = 1.80 m, weight = 90 kg. BMI = 90 / (1.80^2) = 90 / 3.24 = 27.78 (overweight category). Suppose fat mass = 10 kg, fat-free mass = 80 kg → body fat% = 10/90 = 11%.  
- Person B (obese): height = 1.80 m, weight = 90 kg. BMI = 27.78 as well. Suppose fat mass = 40 kg, fat-free mass = 50 kg → body fat% = 40/90 = 44%.  
- Same BMI, very different fat vs fat-free composition — demonstrates BMI’s limitation.

4. Why the correct answer is correct
- The core limitation is precisely that BMI cannot separate fat weight from fat-free weight. That is why it may misclassify muscular individuals as overweight or underestimate adiposity in people with low muscle mass.

5. Why other options are incorrect
- “Elderly and youthful people”: Age groups can influence composition, but the core failure is composition, not simply age.  
- “Males and females”: Sex differences affect typical fat distribution, yet BMI’s limitation is composition; it does not inherently fail only by sex.  
- “Water and muscles”: Water is a component of fat-free mass; the more general and correct distinction is fat vs fat-free mass.

6. Conclusion
The correct answer is fat weight and fat-free weight. This matches the provided answer and is supported by the reasoning and example above.

BMI is only an indirect indicator of body fatness and therefore will not accurately classify all individuals, specifically because it fails to distinguish between单项选择题

类似问题

In the past, people relied on height-weight tables that were based on insurance company mortality statistics, but these were inaccurate because

What is the primary reason why weight is not the most accurate metric to assess fitness, according to the New York Times article “How Fit Are You?”?

If one was to lose weight from dieting over a long period of time, approximately what percentage of the lost weight would be fat and lean mass?

According to experts, a percentage of body fat below the range of ________ is unhealthy.

The human body is made up of fat-free mass and

In the past, people relied on height-weight tables that were based on insurance company mortality statistics, but these were inaccurate because

Percent body fat classifications are significantly different for the two sexes. For example, a female could have a percent body fat that is “recommended” (or healthy) while the same percent body fat could be categorized as “obese” for a male of the same age.

The BMI measurement can overestimate obesity in which individual?

更多留学生实用工具

智能学习助手

风格化写作助手

论文查重助手

文献引用助手

课堂转译助手

课堂笔记助手

Quiz搜索助手

学校历年真题

智能刷题助手

智能匹配练习

希望你的学习变得更简单