What is it called when a persons body weight is lower than the weight range that is considered healthy?

What is it called when a persons body weight is lower than the weight range that is considered healthy?

Assessment of weight and health risk involves using three key measures:

  1. Body mass index (BMI)
  2. Waist circumference
  3. Risk factors for diseases and conditions associated with obesity

Body Mass Index (BMI)

BMI is a useful measure of overweight and obesity. It is calculated from your height and weight. BMI is an estimate of body fat and a good gauge of your risk for diseases that can occur with more body fat. The higher your BMI, the higher your risk for certain diseases such as heart disease, high blood pressure, type 2 diabetes, gallstones, breathing problems, and certain cancers.

Although BMI can be used for most men and women, it does have some limits:

  • It may overestimate body fat in athletes and others who have a muscular build.
  • It may underestimate body fat in older persons and others who have lost muscle.

Use the BMI Calculator or BMI Tables to estimate your body fat. The BMI score means the following:

 BMI
Underweight

Below 18.5

Normal

18.5–24.9

Overweight

25.0–29.9

Obesity

30.0 and Above

Waist Circumference

Measuring waist circumference helps screen for possible health risks that come with overweight and obesity. If most of your fat is around your waist rather than at your hips, you’re at a higher risk for heart disease and type 2 diabetes. This risk goes up with a waist size that is greater than 35 inches for women or greater than 40 inches for men. To correctly measure your waist, stand and place a tape measure around your middle, just above your hipbones. Measure your waist just after you breathe out.

The table Risks of Obesity-Associated Diseases by BMI and Waist Circumference provides you with an idea of whether your BMI combined with your waist circumference increases your risk for developing obesity-associated diseases or conditions.

Risk Factors for Health Topics Associated With Obesity

Along with being overweight or obese, the following conditions will put you at greater risk for heart disease and other conditions:

Risk Factors

  • High blood pressure (hypertension)
  • High LDL cholesterol ("bad" cholesterol)
  • Low HDL cholesterol ("good" cholesterol)
  • High triglycerides
  • High blood glucose (sugar)
  • Family history of premature heart disease
  • Physical inactivity
  • Cigarette smoking

For people who are considered obese (BMI greater than or equal to 30) or those who are overweight (BMI of 25 to 29.9) and have two or more risk factors, it is recommended that you lose weight. Even a small weight loss (between 5 and 10 percent of your current weight) will help lower your risk of developing diseases associated with obesity. People who are overweight, do not have a high waist measurement, and have fewer than two risk factors may need to prevent further weight gain rather than lose weight.

Talk to your doctor to see whether you are at an increased risk and whether you should lose weight. Your doctor will evaluate your BMI, waist measurement, and other risk factors for heart disease.

The good news is even a small weight loss (between 5 and 10 percent of your current weight) will help lower your risk of developing those diseases.

The body mass index (BMI) is a measure that uses your height and weight to work out if your weight is healthy.

The BMI calculation divides an adult's weight in kilograms by their height in metres squared. For example, A BMI of 25 means 25kg/m2.

BMI ranges

For most adults, an ideal BMI is in the 18.5 to 24.9 range.

For children and young people aged 2 to 18, the BMI calculation takes into account age and gender as well as height and weight.

If your BMI is:

  • below 18.5 – you're in the underweight range
  • between 18.5 and 24.9 – you're in the healthy weight range
  • between 25 and 29.9 – you're in the overweight range
  • 30 or over – you're in the obese range

If you want to calculate your BMI, you can use the healthy weight calculator.

Accuracy of BMI

BMI takes into account natural variations in body shape, giving a healthy weight range for a particular height.

As well as measuring your BMI, healthcare professionals may take other factors into account when assessing if you're a healthy weight.

Muscle is much denser than fat, so very muscular people, such as heavyweight boxers, weight trainers and athletes, may be a healthy weight even though their BMI is classed as obese.

Your ethnic group can also affect your risk of some health conditions. For example, adults of South Asian origin may have a higher risk of some health problems, such as diabetes, with a BMI of 23, which is usually considered healthy.

You should not use BMI as a measure if you're pregnant. Get advice from your midwife or GP if you're concerned about your weight.

Further information

  • Healthy weight
  • Better Health: lose weight

Page last reviewed: 28 November 2022
Next review due: 28 November 2025

What is it called when you are below the standard weight range?

underweight. a condition in which a person is less than the standard weight range for his or her height. nutrient-dense foods.

What does it mean to have a body weight that is more than what is considered normal or healthy for one's age or build?

The terms “overweight” and “obesity” refer to body weight that is greater than what is considered normal or healthy for a certain height. Overweight is generally due to extra body fat. However, overweight may also be due to extra muscle, bone, or water. People who have obesity usually have too much body fat.

What happens if you are below average weight?

Weighing too little can contribute to a weakened immune system, fragile bones and feeling tired. You can check if you're underweight by using our BMI healthy weight calculator, which shows your body mass index (BMI). If your BMI is below 18.5, this suggests that your weight may be too low.

What is being heavier than the standard weight range at your height called?

Weight that is higher than what is considered healthy for a given height is described as overweight or obesity. Body Mass Index (BMI) is a screening tool for overweight and obesity.