Body mass index (BMI) is a person's weight in kilograms divided by the square of height in meters. BMI is an inexpensive and easy screening method for weight category—underweight, healthy weight, overweight, and obesity.

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..

'A healthy BMI for women is between 18.5 and 24.9 – this is also the same for men. However, it's important to note that even at the same BMI, women tend to have more body fat than men. A woman's ethnicity and age may also impact their BMI measurements..

Choose minimally processed, whole foods-whole grains, vegetables, fruits, nuts, healthful sources of protein (fish, poultry, beans), and plant oils. Limit sugared beverages, refined grains, potatoes, red and processed meats, and other highly processed foods, such as fast food.

The changes in BMI units ranged from 0.5 to 2.5 between the ages of 70 and 90 years but were greater for women than for men. The absolute differences with age between body mass index (BMI) calculated from current height and height corrected to maximal height before age 40.