Training & Nutrition - Question: How many calories do I need for fuel?

I am a 16-year-old female, who weighs 135 lbs and stands 64.5 inches tall. I lead an active lifestyle and I stand all day long, doing a bit of cleaning and walking about...I also twitch a lot and sway back and forth, so I'm never really still. I also bike at a 12-14 MPH pace (working on endurance) for 14 hours per week and lift free weights (various upper and lower body moves--currently using 10 lb dumbells and working my way up to heavier weights) for 4 hours per week. I sleep 9 hours per night. On average, how many calories do I need per day? I do take one day to rest each week, but I'm just looking for an average number. I have IBS, which oftentimes kills my appetite, so it's helpful to know how many calories I need to eat. Otherwise, I tend to under eat by a long shot and end up getting fatigued and sick.

I ask this because, as a teen, I know that I require more calories than an adult of my size (for the sake of growth and all that jazz). I've tried using the calculator at http://www.bcm.edu/cnrc/bodycomp/bmiz2.html, but I've got no idea how to account for my already active lifestyle AND my exercise.

Thank you for any guidance!:)

Sign up for something like Fitday or the Dailyplate. Use their calculator to figure your basal metabolic rate (roughly), and use it to keep track of your exercise. I wouldn't bother including daily activity type things (work - unless it's hardcore physical, errands, etc), but would include biking, weights etc. Make sure you put in your sleep each night or your BMR will be off.

This won't be exact, but it should give you a pretty accurate picture of the calories you are burning. Then you can track the calories you are consuming from food and aim for a balance that suits your goals.

Both fitday and dailyplate are available for free.

First off, it makes no sense to get a value for your calorie burning if you do not carefully measure your calorie intake. Most people do not weigh their food or even keep track of their consumption by estimation.

Also, estimations on calorie burning are pretty problematic. One can measure calorie burn rates and it is not that hard to do if you have the expertise and a fully equipped laboratory. I just bet that no one here has both of those. Otherwise, all of this is just a guess.

You can go to one of the many web sites that offers estimations on calories burned. But individuals can be pretty different. There are people who never sit still. They fidget all the time and tend to jump up and move around frequently. There are other people who just sit still and relax. These two people if the same height and weight would probably have the same estimated calorie burn. But I bet the person who fidgets burns about 50% more calories in the "relaxed mode".

Also this is all based on observer estimation. People tend to not be horribly objective about themselves and are prone to error. Some people will greatly over estimate their fitness, work out intensity and so on. Other people will go just as far in the other direction.

You can get an estimate on this stuff. But there is a very high degree of unreliability in the estimate. It is better than nothing. It will give you a decent idea of your caloric burn just do not put a whole bunch of faith in it. But a check on whether you are in balance with your calorie intake and calorie burn is your weight gain. Another confounding problem you have is being an adolescent and that provides yet another variable into the whole mess.

Most calorie estimators for cycling overestimate the calories consumed, sometimes by quite a bit. Using a power meter is more accurate.

But it's a lot easier to just monitior your weight. If it goes up, eat less. If it goes down, eat more.
If you want to be more accurate, get one of those body composition scales. The % of body fat they report is not accurate but it is consistent (if you take hydration into account and weigh/measure yourself at the same time each day). The better ones report hydration and muscle+bone mass as well. You can use those numbers to track your body fat percentage. That method will take added lean body mass into account where going just by weight won't.

Pat, that made a WHOLE lot of sense. I, as a matter of fact, do weigh my food and track my calories er the suggestion of my doctor. He did not give me advice on how much to eat, though. I shall just have to play with it , I guess...you really opened up my eyes to reality, though. Thank you.

Sunflowered.

So you are weighing your food. It has been shown that people who weigh their food tend to eat fewer calories. It makes you eating intentional. Another thing you might try is to keep track of the grams of fat, carbo and protein in each food you eat. If you want to go even further, you could keep track of saturated fat and trans fat too. The point of this is foods that are high in fat tend to be very calorie rich. People can get quite a few calories without feeling like they are eating much.

As for exercise, it takes a potload of exercise to burn a lb of fat. For me, I have seen calories burned per mile of cycling differ by 100%. Does that amount of variance give you much faith in the numbers?

I figure that in order to burn a lb of fat, I have to ride at least 70 miles. It also means that I do not eat any additional calories in the day as a cosequence of the extra activity. That is NEVER true.

Now I did manage to lose 10 lbs in 14 days. But those 14 days were riding long distances up and down mountain passes in the Rocky Mountains. I was also very careful about what I ate. So one can lose weight fast with a whole bunch of aerobic workout. There were other people on the tour that gained weight. They ate the 3 meals provided during the day and went into town and had the largest cheese burger, the largest fries and topped it off with the largest sundaes they could find. No matter how much you exercise, you can more than make up for it by eating calorie rich foods.