# Seeking for the math in calories

• Can someone tell me, or give a web site, or a book name that shows the math on how to figure your calorie intake at the weight you are at and how much you need to take away alone with your height?

I know that it is 3,500 calories to a pound and the popular number is taking away 500 calories for the calories that is keeping you at the weight you are at to lose fat but I have some missing equations in my head I can't figure out.

Like if you are at 215 Lbs. What is the math equation that tells you the number of calories that is keeping you at 215 pounds

then the math equation to take off a pound or two a week. I am sure I am going to need my inches in how tall I am to factor in.

Yes I know there are calculators on line to do this for me but I want the good old math standard and equations locked into my head because there are days I am not going to be near a computer and it is good to know.
• Here's the problem (err, the main one)--there is NO FORMULA that works for everyone. 2 people the same height and weight and age and gender can need 2 very different caloric intakes to maintain their weight based on differences in body composition, activity level, metabolism, and genetics.

That said, many online calculators use the "Harris-Benedict" formula. You can Google this to find the actual formula, but I'm going to say from memory that it's such a complex (read: annoying) equation that you're better off just waiting until you can get to a computer to use an automatic calculator.

Here, I did my own quick Google, and this is the Harris-Benedict formula for determining your basal metabolic rate (BMR):
Adult female: 655 + (4.3 x weight in lbs.) + (4.7 x height in inches) - (4.7 x age in years)

There are, however, forulmas other than the Harris-Benedict floating around out there--it's just the only one I could remember off the top of my head.
• I read a rather simplistic "formula" the other day in Women's Health magazine. Take your current weight and multiply by 10. That gives you an APPROXIMATE number of calories to eat to maintain. Deduct from there to lose.
• Another very simple one is 2 times your weight by 7. So if you are 215 lbs. then in order to lose you should eat 1500 cals. But the only way to know for sure is through trial and error. No one or nothing can tell you for sure for sure just what the right number is.
• Quote: I read a rather simplistic "formula" the other day in Women's Health magazine. Take your current weight and multiply by 10. That gives you an APPROXIMATE number of calories to eat to maintain. Deduct from there to lose.

See that just doesn't seem right, wouldn't that be a bit low for some people...Like your ticker is 140 so 1400 calories to maintain?? To loose one lb you need 500 calories less per day...giving you 900 calories a day!! I thought under 1200 was a BIG BIG no no....I guess with added excerise you could raise it to 1200 though....(I want to eat a little more than 1200 calories!!)

That just doesn't seem right with people whose weight is under 150....This is all sooo confusing....LOL
• Quote: That just doesn't seem right with people whose weight is under 150....This is all sooo confusing....LOL
Which is EXACTLY why there is NO formula that works for everyone! As robin mentioned, trial and error is the ONLY way to know what works for YOU.
• It sounds like you've had some good input on estimating your basal calorie needs. I won't repeat the same stuff - the reality is that it's all an estimate and you have to experiment to find what works best for you.

If you're interested in knowing exactly what your calorie burn is, on a day-by-day basis, I can't talk enough about a device I use called a bodybugg. It's kind of like a pedometer on crack - you strap this thing to your tricep which registers your body temperature, movement, and skin galvanic response (i.e. how much you're sweating), as well as the ambient temperature, and uses a set of algorithms to estimate your caloric burn on a constant basis. In combination with a food log, it gives you a direct measure of your "calorie deficit" - how much less (or more) you're eating than burning, and allows you to set goals for an optimal deficit which will allow for weight loss.

I always struggled with the standard calorie calculations - it just seemed too unreliable. I had my RMR (resting metabolic rate) tested using a "BodyGem" at around 1400 calories (meaning that if I just lie in bed blinking at the ceiling, I'll burn 1400/day), which helped me see that I was under-eating whenever I was "on a diet" and aiming for 1200 - if I burn 1400 doing nothing and I stay active all day, I'm obviously going quite low to eat 1200.

But it wasn't until I got the bodybugg that I realized just how much my daily burn can vary. I've been using it on and off for over a year, and I've seen days where I've burned over 3000 calories without a workout (when I'm on my feet all day and walking up and down the hallways a lot) and days where I'm sitting on my butt at the computer for 8 hours and even a 4-mile run doesn't bring me above 2500 for the day. Frankly, knowing your resting metabolism doesn't really tell you much when you compare it to measuring your actual daily output.

Before this sounds like a cheesy infomercial, I'll let you know that I've bounced around, lost over 15 pounds and then gained it back in the last year (and I'm now on my way back down, SLOWLY, again) - this tool isn't a guarantee of weight loss any more than any other gadget. However, it is a very handy tool that can really help you keep things in perspective - I no longer beat myself up if I eat above my standard calorie goals, since I can see that I may have exerted myself more today or yesterday and my body's just trying to rebuild. When I can see a daily deficit of 600-1000 calories, and the 1.5-pound average weekly loss that reflects the 700 calorie average deficit, I know I'm on the right track, even if I eat 1800 calories one day (and burn 2400) and 2400 the next (and burn 3500!). When I was just counting calories, I would be kicking myself for days about going over my "limit." It works pretty well for me - I'm a science geek and more information is always better.

Edit to add details - FYI, this sucker isn't cheap! It's \$400 for the armband and the first 3 months of the web service, and \$15/month or \$99/year for continued service (it's only a web-based software, so a slight ongoing expense). However, I bought mine when I was dropping my gym membership and consider it a much better investment - I get a lot out of it and after the initial expense it's a pretty reasonable cost for the ongoing service. If you're interested, let me know - I can give you more information but don't want to sound like a salesman!
• Weight LOSS calories for most people range from 1200-2000 calories a day. The more that you weigh, and the more active you are, the more you can eat per day and still lose.

2000 calories a day is more for men, OR for women who have a LOT to lose-say starting at 250 pounds or over.

Jill is 100% correct in the fact that calculators don't mean beans to some people. They don't work for me-only trial and error does.

Start out at the higher end-say 1800 calories a day for two weeks. Weigh in before you start, and weigh in after the two weeks. If you lost 1-2 pounds each week (or 2-4 at your weigh in after two weeks) then you are at a good level for you. If you didn't see any loss, then move it down by 100 calories a day to 1700...and then see what happens after the next week or two.

When you are going through this process-do NOT weigh in every day!!! Some people lose at a rate of 1 pound per week, which means that you very well might weigh in 3 days in a row and not see any change-this does not mean it isn't working-it means you need to take a scale break!

I recommend starting high and slowly going low for a couple of reasons-if you start off at the low end, say 1200-1300 a day, and your body adjusts to that, what happens 20-30 pounds down the line when you plateau? You don't have much wiggle room to break that plateau with a calorie change-the only real option then is to increase your exercise. You should do that anyhow over time...but you don't want to get stuck at 1200 calories a day, the low end, too soon.

Trial and error...trial and error.
• Quote: See that just doesn't seem right, wouldn't that be a bit low for some people...Like your ticker is 140 so 1400 calories to maintain?? To loose one lb you need 500 calories less per day...giving you 900 calories a day!! I thought under 1200 was a BIG BIG no no....I guess with added excerise you could raise it to 1200 though....(I want to eat a little more than 1200 calories!!)

That just doesn't seem right with people whose weight is under 150....This is all sooo confusing....LOL
I agree that this formula is overly simplistic and wouldn't work for me because I won't go below 1200 calories per day (but it is a good starting point for someone closer to 200 pounds). Because I am 140, the formula states that I should maintain at about 1400 calories, so in order for me to lose a pound a week by eating 1200 calories, I would have to incorporate EXERCISE that would use up another 300 calories per day. You know, the old eat less move more concept! I only offered this simplistic version because the original poster said she was over 200 and she could very possibly cut 500 calories and still come in at a very decent caloric intake and lose weight. Sorry to everyone if I caused any controversy!!
• No controversy here-

FYI-when I was over 200 pounds, I lost the first 10-15 easily at 1800 calories...I didn't need to take 500 from 2000, and eat 1500 a day that soon. I don't usually need to drop to the 1500 level until I am around the 180 weight range.

Everyone is different...that is why I don't use calculators.
• You don't really need a calculator to do this. If you currently weigh 215 lbs and you are maintaining this weight, just track how many calories you eat per day for a week or so and you'll know how many calories are keeping you at this weight. Then subtract 500 from that and you should start losing weight (give yourself at least a week, maybe two, to start seeing results). If you don't lose weight, then subract another 100 and give yourself another week to see results. Just keep subtraction 100 until you are losing weight at a rate you are comfortable with.

I agree with everyone else that the online calculators are not terrible accurate. For one thing, none of them includes body fat%, which is an important consideration in terms of calorie burn. Someone with 25% body fat is going to be able to maintain and lose weight at a higher level of calories than some of the same height, weight, and age with 35% body fat. Muscle burns more calories; this is why strength training is good for weight loss. Yet, I've never seen a formula or website that asks for this information.

Despite having said that I don't think they are accurate, here are a few websites with these calculators:
Be sure to pay attention to whether or not the calculators are compute the calories you need to maintain vs. lose weight.

It's also possible to get your resting metabolic rate (RMR) tested. Some gyms can do it (I know Bally's does it) and I think someone once mentioned that Kaiser Permanente can do it. This would probably be more accurate that the online calculators.