Being overweight or obese can negatively impact your health. But how do you know if your weight has crossed the line into unhealthy territory? There are a few different ways to assess whether excess fat is putting your health at risk.
BMI Categories
One of the most common ways to estimate if someone’s weight is unhealthy is using Body Mass Index (BMI). BMI is a calculation that uses your height and weight to estimate your body fatness. It is used as a screening tool to indicate if someone may be underweight, normal weight, overweight or obese.
Here are the BMI categories:
| BMI | Weight Category |
|---|---|
| Below 18.5 | Underweight |
| 18.5 – 24.9 | Normal weight |
| 25.0 – 29.9 | Overweight |
| 30.0 and above | Obese |
A BMI of 25-29.9 is considered overweight, while a BMI of 30 or more falls under obese. So according to BMI categories, you would be considered unhealthy if your BMI is 25 or higher.
Body Fat Percentage
While BMI is easy to calculate, it does have some limitations. BMI is based solely on height and weight, so it doesn’t directly measure body fat. Two people with the same BMI may have very different amounts of body fat based on their muscle mass.
A more accurate way to assess unhealthy levels of body fat is to directly measure percentage of body fat. There are a few different ways body fat percentage can be measured:
- Skinfold test – Uses calipers to pinch skin at different body sites to estimate fat.
- Bioelectrical impedance – A low-level electrical current is sent through the body to estimate fat and fat-free mass.
- Hydrostatic weighing – Calculates body density by weighing a person underwater.
- DEXA scan – Uses low-dose x-rays to measure bone density and estimate fat mass.
While methods vary, general body fat percentage recommendations for health are:
| Classification | Women | Men |
|---|---|---|
| Essential fat | 10-13% | 2-5% |
| Athletes | 14-20% | 6-13% |
| Fitness | 21-24% | 14-17% |
| Acceptable | 25-31% | 18-25% |
| Obese | 32% and higher | 25% and higher |
So according to body fat percentage recommendations, women with more than 31% body fat and men with more than 25% would be considered to have unhealthy levels of body fat.
Waist Circumference
In addition to BMI and body fat percentage, waist circumference is another simple way to estimate unhealthy levels of abdominal and visceral fat. This abdominal fat located deep in the belly is associated with metabolic abnormalities and increased disease risk.
Guidelines for healthy waist circumference are:
- Women: Less than 35 inches (88 cm)
- Men: Less than 40 inches (102 cm)
So if your waist size exceeds those numbers, it’s an indication you may have unhealthy excess abdominal and visceral fat.
Associated Health Risks
Carrying unhealthy amounts of body fat, especially around the abdomen, is associated with increased risks of:
- Type 2 diabetes
- High blood pressure
- High cholesterol
- Heart disease
- Stroke
- Cancer
- Osteoarthritis
- Sleep apnea
- Gallstones
- Fatty liver disease
The more excess fat you have, the greater your risks for obesity-related diseases. However even modest amounts of excess fat can negatively impact metabolic health.
Assessing Overall Health
While numbers like BMI, body fat percentage and waist circumference give quantitative guidelines, it’s also important to look at overall health.
Two people with the same BMI or body fat may have very different metabolic health and disease risk based on factors like:
- Exercise and fitness level
- Diet quality
- Stress level
- Smoking status
- Blood pressure
- Cholesterol and triglyceride levels
- Blood sugar control
- Family history
So while numerical cutoffs can serve as useful screening tools, it’s important to consider the whole picture when determining if excess fat is impacting your health.
Conclusion
There are a few different ways to estimate if excess body fat has crossed over into the unhealthy range:
- BMI of 25 or greater
- Body fat percentage exceeding 25% in men and 31% in women
- Waist circumference over 40 inches in men and 35 inches in women
Meeting any of those criteria indicates you likely have unhealthy levels of body fat that could increase your risks for chronic diseases. However, overall health and disease risk are influenced by many factors beyond just BMI, body fat percentage or waist circumference. The best approach is to consider all these measures in the context of your overall diet, exercise, medical history and other health habits.