Body mass index (BMI) is simply a relationship between weight and height. For the vast majority of people, BMI will give a good measure of whether the weight is normal or needs to change. Some populations such as bodybuilders will have a higher BMI because of muscle mass. This tool cannot distinguish between muscle and fat so it is up to you to decide whether you have excess fat or are muscular. To calculate your BMI, simply enter your weight and height into the form below and click calculate.
What is BMI and is it reliable?
Body mass index (or BMI for short) is a ratio between your weight and height that is used to asses your risk of certain health problems such as cardiovascular disease, diabetes and strokes. Numerous studies have shown a correlation between an increased ratio of weight and height with an increased risk of health problems. Generally, the more you weigh, the unhealthier you are. This doesn't mean that being skinny is perfect, but losing weight in a healthy manner will improve your overall health by lowering your risk of some serious health problems.
BMI is only one of the ways to look at your overall health. One problem with BMI is that it doesn't take into account what type of weight you carry. If you are overweight but muscular, you are obviously healthier than someone who is overweight and fat. Since BMI can't tell thedifference between fat and muscle, you need to either decide for yourself whether its accurate for your body type or use another method such as body composition. However, if you eat as much as you want and rarely exercise, your overweight or obese BMI categorization is most likely accurate.
What are the BMI categories?
Your BMI is a number, the ratio between your weight and height. Categories were set up to make it easier to read what your BMI means. A BMI under 18.6 is considered underweight while anything above 24.9 is considered overweight (obese for a BMI of over 30). A BMI between 18.6 and 24.9 is considered ideal.
Whether you are underweight or overweight, the fix is fairly simple. Calorie balance is what controls weight. Calorie balance is the difference between the amount of calories you eat and the amount of calories you burn. Whether or not you're actively controlling your weight, calorie balance has three possibilities: losing weight, gaining weight or maintaining weight. Your first step in your weight controlling journey is to figure out how many calories your body needs each day. The calorie calculator uses your age, size, gender and activity level to estimate your daily caloric needs. Only by figuring out how many calories your body uses can you move onto the next step of weight control, calorie control.
Losing weight requires that you create a calorie deficit. A calorie deficit is a state in which you burn more calories than you eat. If the calorie calculator estimated that your body burns 3,000 calories per day, eating 2,500 calories per day would create a 500 per day calorie deficit. This calorie deficit forces your body to look for energy from non-food sources, typically body fat. Over time, this causes weight loss.
The bigger your calorie deficit, the faster you'll lose weight. You can create a calorie deficit by eating less, exercising more or a combination of both. Avoid cutting your calories too drastically which will cause the body to slow down your metabolism in order to compensate for the lower intake. If you find yourself not losing weight fast enough, consider trying a more intense and longer exercise routine.
Gaining weight requires that you create a calorie surplus. A calorie surplus is a state in which you eat more calories than you burn. If you eat 500 calories more than you burn, your body will either take that extra energy and increase your muscle mass or turn it into fat. If you are engaged in a strength training routine, you will gain muscle. If you only create a calorie surplus and watch TV all day, you'll get fat.
Maintaining weight is fairly easy, simply eat the amount of calories that your body needs and you will neither store/burn fat or build muscle. Just because you're already at an ideal weight doesn't mean you should ignore the principles of living a healthy lifestyle. Weight is only one indication of overall health. Your exercise routine and diet will also determine your overall health. There are plenty of people at an ideal weight who are also unhealthy.
The Bottom Line
Keep in mind that BMI is not the only measure of health. Being a few pounds overweight while eating healthy and exercising isn't as bad as being in the normal weight category while smoking, eating junk food and leading a sedentary lifestyle. There are plenty of ways you can measure your overall health and BMI is simply one of them.