The BMI, or body mass index, is used to assess a person's appropriate weight range based on their height. BMI is useful for assessing risk because waist circumference measures the quantity of central fat.
 |
| Photo by Anna Shvets from Pexels |
For most persons above the age of 18, the BMI is a helpful assessment. However, it is merely a guess, and it does not account for factors such as age, race, gender, or body composition.
An increase or reduction in BMI can have a major impact on physiology at the cellular level. Insulin resistance, inflammatory states, and cognition have all been linked to BMI in studies.
Classification and Definition of BMI
BMI, or body mass index, is a statistical indicator that uses a person's weight and height to calculate body fat in males and females of any age.
BMI = weight (in kg)/ height2 (in m2) is determined by dividing a person's weight in kilograms by their height in meters squared. The individual's BMI number is then calculated using this equation.
Individual differences exist, and BMI alone is inadequate to characterize a person as fat or malnourished. For example, because of their increased muscle mass and weight, a raised BMI does not immediately connect to their health condition among top athletes and bodybuilders.
The BMI number and classifications are provided below; the NIH and the World Health Organization utilize these classifications for BMI (WHO Scale for BMI)
- Severely underweight - BMI less than 16.5kg/m^2
- Underweight - BMI under 18.5 kg/m^2
- Normal weight - BMI greater than or equal to 18.5 to 24.9 kg/m^2
- Overweight – BMI greater than or equal to 25 to 29.9 kg/m^2
- Obesity – BMI greater than or equal to 30 kg/m^2
Risks associated with being overweight.
Being overweight increases the risk of a number of serious diseases and health conditions. Below is a list of said risks,
- High blood pressure
- Stroke
- Type II diabetes
- Higher levels of LDL cholesterol, which is widely considered "bad cholesterol," lower levels of HDL cholesterol, considered to be good cholesterol in moderation, and high levels of triglycerides
- Coronary heart disease
- Gallbladder disease
- Osteoarthritis, a type of joint disease caused by the breakdown of joint cartilage
- Sleep apnea and breathing problems
- Certain cancers (endometrial, breast, colon, kidney, gallbladder, liver)
- Mental illnesses such as clinical depression, anxiety, and others
- Body pains and difficulty with certain physical functions
- Low quality of life
- Generally, an increased risk of mortality compared to those with a healthy BMI
As can be seen from the list above, being overweight may have a variety of unpleasant, and in some cases deadly, consequences. In general, a person should attempt to keep their BMI below 25 kg/m2, but they should first visit their doctor to see whether they need to make any lifestyle adjustments in order to be healthy.
Being Underweight carries a number of risks.
- Malnutrition, vitamin deficiencies, anemia (lowered ability to carry blood vessels)
- Osteoporosis, a disease that causes bone weakness, increases the risk of breaking a bone
- A decrease in immune function
- Growth and development issues, particularly in children and teenagers
- Possible reproductive issues for women due to hormonal imbalances that can disrupt the menstrual cycle. Underweight women also have a higher chance of miscarriage in the first trimester
- Potential complications as a result of surgery
- Generally, an increased risk of mortality compared to those with a healthy BMI
