Measures of obesity (Edexcel GCSE Biology Combined Science): Revision Notes
Measures of obesity
Both BMI (Body Mass Index) and the waist-to-hip ratio are tools used to assess a person's general health, particularly in relation to obesity. While these values provide a useful starting point for understanding someone's health, they do not account for all factors, such as muscle mass or distribution of body fat.
Body Mass Index (BMI)
Used as a guide to help weight description calculated from height & weight.
| Body Mass Index | Weight Description |
|---|---|
| Below 18.5 | Underweight |
| 18.5 • 24.9 | Normal |
| 25 • 29.9 | Overweight |
| 30 • 40 | Moderately Obese |
| Above 40 | Severely Obese |
If you eat high fat/sugar diet/not enough exercise you are more likely to take in more energy than you use which is stored as fat so more likely to have high BMI
Problems
- It Isn't reliable for athletes as muscle weighs more than fat so they could have high BMI but not be over weight
Waist to Hip Ratio
Definition: This ratio measures the proportion of fat stored around the waist compared to the hips. It is useful for assessing the risk of developing health problems related to body fat distribution.
The higher the ratio the more abdominal fat
Obesity Threshold:
The World Health Organisation (WHO) defines obesity using the waist-to-hip ratio as:
- Above 0.85 for women.
- Above 1.0 for men.
Health Risks:
- A high waist-to-hip ratio indicates a higher amount of abdominal fat, which is linked to increased risks of heart disease, type 2 diabetes, and other health problems.