Body Mass Index is actually the measurement of your weight for your body surface area and it’s considered a reliable indicator of body fatness for most people.The two deciding factors are your weight and height. A BMI less than 18.5 is underweight. Below 25 is normal. A BMI of 25 through 29.9 is overweight, and 30 or higher is considered obese. However, these days many experts are questioning whether the BMI is an accurate way to measure a person’s fitness levels and general health. For example, people who are normally muscular or athletic or have high bone density would have a BMI comparable to someone who’s out of shape but that doesn’t mean they’re more prone to obesity-related lifestyle diseases. Therefore, nowadays there’s a greater tendency to measure a person’s body fat percentage which many believe is a more accurate indication of one’s health and well-being.