Welcome to Gaia! ::

There seems to be more growing people interested in getting fit and healthy on gaia than I meet up with in other places. Even though there are more kids, tweens, and teens around I see lots of them using an adult BMI calculator. When you're growing you have a million things going on, not to mention you're supposed to have a little baby fat (when you're active and eat clean and still have some pudge? That's probably just baby fat.) until some point in puberty. BMI for the adultlet! Because BMI isn't the best judge of a healthy fit person to begin with (it can't tell the difference between fat and lean muscle) might as well try and keep it as much on the up and up for people under 18.
this one has a calorie guide for your height,weight,age, and activity level. I have no idea if it is accurate or not. Sorry.Tone Teen is a site I found last night on accident and it may or may not be a good site.

As with all this internet stuff, talk to your doctor or professional.

You burn calories of every minute of every day, calories are the food your body eats so it doesn't die. I'm burning calories right now sitting at the computer and I'm even burning a bit more by exerting my body with typing. It's just not a large number.

How many calories you burn at rest is called "Resting Metabolic Rate"(RMR) and my varisty soccer playing brother and my fit co-worker burn more just sitting watching TV than I do because my body has a higher percent of lazy fat than they do.

"Basal Metabolic Rate" (BMR) is the amount of calories you burn everyday just to keep your body alive that with with no added activity.

So we all want to lose fat and gain lean muscle mass and have our BMR and RMR go up. In addition to exercising more to burn more calories and eating less food than we need to maintain our weight. Because having the diet and exercise is what will make us lose and also what will make the BMR and RMR go up (assuming you lose fat and not muscle to "weigh" less) so yay for win-win situation!.

So you burn while watching TV sitting down but you burn even more if you were to walk in place in front of the TV. Walking burns calories and jogging burns more. But if you you like to walk briskly as your exercise and you would do it longer than if you jogged than it may be your lower calorie workout at a longer interval burned more. Cool.

When we go on super low calorie diets our bodies freak out and try and conserve calories so the body doesn't die (it thinks there is a famine or why else wouldn't you be eating?) and so your metabolism slows down to compensate.

That's why your doctor and people will tell you the best way to lose is slowly by burning more fat through exercise and eating less calories than you need to maintain your body weight. Weight bearing exercise is what builds lean fat burning muscle so that is usually recommended too.

If you ask your doctor our some other professional to help you figure out how many calories you should be eating and how much to exercise I'm sure they woud be happy to help.
^^

We all start out not knowing things and then we get interested and then we find stuff and learn stuff and learn some stuff we thought we learned is wrong and discard that stuff and then we can help other people learn stuff. ^^

I'm not sure how old you are but having high school biology is actually a great base for fitness stuff. Learning the internal stuff. I love biology, it's one of my favorites. ^^ AP Biology was the best class I took in high school. Human Anatomy in university is also up there (although it was hardXD)