Eating fewer calories than you burn is required to lose weight, which is known as energy balance.
Controlling calorie intake is so important because if you eat more calories than you burn, you gain weight, and if you eat fewer calories than you burn, you lose weight.
So how do you accurately measure your calorie burn? Is a simple calculation really good enough?
What Is Your Calorie Burn?
Your calorie burn is the sum of three components:
1) Basal Metabolic Rate (BMR) – This is how many calories your body burns at rest. Even while you rest, your respiratory system is operating, digestive system, and other body processes that require energy (i.e. burn calories). Your BMR represents roughly 65% of your total calorie burn.
2) Activity Level – This is how many calories you burn that requires physical movement, or when your body is in motion. The more active you are, the more calories you will burn. Activity level represents roughly 20% of calorie burn, which depends on how active you are of course.
3) Thermic Effect of Food – Digesting food requires energy, but typically the thermic effect of food only adds up to about 10% of the total amount of calories you burn.
Calorie Burn Method #1: Harris Benedict
Most calorie burn calculators found on the internet use the Harris Benedict (HB) method, which takes into account your age, weight, height, and sex to arrive at your BMR. But we still have to figure out your activity level, so that BMR value is multiplied by an “Activity Multiplier” to get your total calorie burn (see equation at bottom of post). The thermic effect of food is already reflected in your BMR calculation.
Notice that the HB method does not take into account your body composition. Individuals with more muscle tend to be more metabolically active and burn more calories. The HB method overestimates calorie burn for individuals with a high body fat percentage and underestimates calorie burn for those with low body fat (and thus more muscle). While it’s not perfect, the HB method is a very helpful starting point.
Calorie Burn Method #2: Katch & McArdle
The Katch and McArdle (KA) method takes into account your body composition to arrive at your BMR and for that reason is considered to be more accurate. The KA method uses the same activity multiplier as the HB method, but has a big downside of its own. The KA calculation depends on your body fat measurement, which may not be accurate (depending on what type of body fat measurement you are using). I would definitely take the KA method over the HB method, but they usually only vary for the average person by a few hundred calories on the high end (for KA equation, see bottom of post).
Calorie Burn Method #3: Measure BMR & Activity Level
A more precise way to measure your BMR is with a metabolic analyzer. If you fear you have a very slow metabolism, this may be a smart idea for you. How it works is you breathe into a tube for around 10 minutes and the analyzer gives you a reading. Because a Metabolic Analyzer can cost thousands of dollars, it’s best to try to find a nutrition practice, or hospital that charges for the test per reading (usually around $150). Even the metabolic analyzer has its drawbacks because your BMR can fluctuate depending on a number of factors. Still, it’s considered the gold standard of BMR measurement.
The best way to measure your activity level is using a calorie tracker like a FitBit, which attempt to measure your movement with accelerometers. None of these trackers is scientifically proven to accurately measure calorie burn and they range in price from $99 to $299. A couple challenges these trackers face is measuring your calorie burn when cycling on a bike, or weightlifting. I think these calorie trackers are definitely interesting and have potential, especially as a motivational tool to help people to get off the couch.
So how the heck do you accurately figure out your calorie burn if your BMR is a moving target that’s tough to assess and your activity level is just as challenging? In my opinion, starting out with the HB/KA methods will give most people a very good idea of calorie burn, but ultimately you need to validate them with measurable results (i.e. weight loss, or weight gain).
Calorie Burn Equations
Harris Benedict Method
BMR Men: = 66 + (6.23 X weight in pounds) + (12.7 X height in inches) – (6.8 X age)
BMR Women: = 655 + (4.35 X weight in pounds) + (4.7 X height in inches) – (4.7 X age)
Katch & McArdle Method
BMR (Men + Women) = 370 + (21.6 * Lean Mass in kg)
Lean Mass = weight in kg – (weight in kg * body fat %)
1 kg = 2.2 pounds, so divide your weight by 2.2 to get your weight in kg
(Both HB + KA Method use same activity multiplier)
Little or no exercise, desk job = 1.2 x BMR
Light exercise, sports 1 to 3x per week = 1.375 x BMR
Moderate exercise, sports 3 to 5x per week = 1.55 x BMR
Heavy exercise, sports 6 to 7x Per week = 1.725 x BMR
Thanks for breaking everything down! The way you present information makes it very easy to understand. I also really enjoyed your Get Lean Guide report and learned a lot, even though I majored in biochem in college. I will definitely check back to see new posts!
Great article. Like a good credit card our bodies have a fair rewards points system, with the expense of cardio and strength training yielding passive calorie burn by raising our BMRs.
The BMR calc is great, I just laid it out in excel
Also, just have to mention Katch – he’s a prof at the UofM and I took his class – he’s exactly as you would imagine
I really like this section. You have made it much easier to understand BMR. It is also the first time I have seen calorie burn explained in such detail. Thanks.
Best explanation ever for BMR.
Best explanation for BMR.
I’ve always wondered — how much exercise do I need to do to lose a pound? Is there a simple equation to get that answer? Thanks!
1 pound of fat has 3500 calories, so in theory, if you burned 500 calories more than you eat per day, then you will lose roughly 1 pound of fat per week. You can also create a calorie deficit simply by eating less. In the real world, sometimes the math doesn’t work perfectly, because hormones can impact the rate of fat loss and our metabolisms can fluctuate, but I think the calorie balance equation (i.e. calorie intake vs. calorie burn) is still very helpful.
How do I take into account my activity level if I exceed the number of times of workouts per week involving ‘Heavy Activity’? What kind of multiplier should I have if it’s 8-10 times per week instead? Thanks.
@Ross – Wow, this comment slipped right past me! Sorry for the very, very late reply. The answer to your question is it depends. If you have 8-10 grueling workouts (intense sprints in the morning, then intense weight lifting in the evening), you will definitely need to increase the activity multiplier by whatever increment you think your workout is harder, or more frequent. So the difference between light, moderate, and heavy is roughly .2, then you can add .2, or .4 to the heaviest exercise level, which would imply 1.9-2.1 multiplier. Keep in mind some athletes like Michael Phelps literally eat 10,000 calories per day, because they are working out all day long. Hope that’s helpful!
Hi, I finally reached my goal weight of 134 and want to maintain it. Im sedentary meaning I have a desk job and ahave no time for exercise! So, to maintain my weight would I have to eat 1728 calories a day. Im 20 and 5″3.
Thank you 🙂
@Mary – The only way to validate a certain calorie level is to weigh yourself each week and see for yourself if it’s the right calorie level. Any calculation will simply be an estimate. Your calorie estimate based on the stats you provided sounds reasonable to me…and congrats on reaching your goal weight!
Also I heard maintaining carbs at 150 grams is a good idea, is that true or just a myth?
@Mary – I would call that a generalization. I think 150 grams of carbs is a reasonable level for someone who is not very active. My take on carbs is to choose them wisely and eat just enough to maintain your energy levels. No more. No less. 150 again sounds reasonable to me, and you can also play around with going even lower and seeing how it affects your energy levels. 150-200 grams is the sweet spot for me.
Great article. Thanks. I came up with 1566 for my BMR and 2427 calculating the activity multiplier. So does that mean my body burns approximately 2427 calories a day between activity and basic function and if I eat more than that I’ll gain weight and less than that I’ll lose?
@Kat – Yes. Exactly. Do keep track of your body measurements to validate the calculations though, as they are just helpful guidelines.
Hey, I’m still 12 years old and my weight is 50 kg and my height is 5ft 1 and i want to be 42kg but all I can find is adult weight loss programmes so how much calories am i meant to eat per day if i want to loose the extra weight? ps my activity level is moderate
Please answer soon
@Confusedgirl – you should consider reaching out to some of your school counselors to see if you can meet with a knowledgeable nutritionist. Here’s what I tell adults – At the end of the day, whatever calorie level you choose, you need to validate it with weight loss. In fact, you may be able to lose the extra weight without even counting calories at all if you focus on eating natural, unprocessed foods that fill you up but do not provide many calories.
sorry I meant light activity
So if my BMR is 1300, and my activity multiplier brings me up to around 2100 and I still eat around 1300 calories, will that technically bring my overall daily calories down to 500 and put me in “starvation” mode or slow down my metabolic rate over time? I used to eat 1200 a day and work out burning about 400 cals a day, but the math never added up (ended up gaining weight or losing very little leaving me frustrated and confused) and people told me I needed to eat more. What do you think?
@bt – how much do you weigh, how tall are you, and what is your approximate body fat percentage? My guess is you are coming from the “How to calculate your calorie intake” post which I purposely closed comments because I was getting inundated with questions I just couldn’t handle myself. If you want a much more in depth answer to your question, happy to set up a coaching call, but in the meantime, I will give you my quick opinion.
Hey, I have worke dmy butt off and have lost just about 100lbs in the past year. im 15 lbs away from my goal weight witch is 150 and i got lost reading cause i clicked over to another page so could you please just give me some advice. for the most part i eat around 1000 cal. and just about every day im on the trid mill burning all of it off if not all atleast half. could you give me a about how many calories i should eat if i wonna cut back working out to about 3 or 4 days a week rather than every day! im so tired of working my but off but im not ready to give up! i just a little change in it for a while a slower paces. im 19 years old female 165 and 5’7. thanks alot for the articale!!!
@Amanda – Congrats on your weight loss! That’s fantastic news. I think this was the article you are looking for: How Many Calories Should I Eat To Lose Weight?. My best guess is around 1400-1600 calories could work well. You always want to track your results of course.
Thanks for this wonderful article which has really helped me! I have always thought I was under eating (confirmed now its true). My BMR is around 1600 (Katch/McArdle). However, my calorific intake has been 1200 (B.S. thinking that I would accelerate my weight loss). I noticed I had started gaining weight since my fat % increased. This was so confusing despite my vigorous weight lifting routines 3 times a week (113 Kcal per hour). Once I started taking into account on activity levels into my BMR, I am consuming at least 1800 Kcal per day. This has reversed the weight gain effect of under eating below my BMR.
@Ngamu – That’s awesome news. Congrats!
I’m seventeen and female and the Harris Benedict method put my BMR at almost exactly 2,000, but I only eat about 1700 a day and yet my body fat percentage keeps rising! Does anyone have ideas as to why this could be? I had pretty severe anorexia a few years ago and i’m wondering if that could have permanently screwed up my metabolism.
It sounds like you should consult with your doctor, or a nutritionist. I’m not aware of metabolism being permanently reduced unless muscle mass, or body mass is reduced.
Hey Marc, I would like to run something by you. I’m a 150 lb, 5’6″ guy trying to get a six pack. I am relatively lean and I workout 3 times a week at high intensity. My workout consists of HIIT training and intense lifting. I train abs only three times a week. My abs feel pretty solid and I am starting to see definition in my obliques. However, I cannot seem to get any definition in my core. I am guessing it is do to diet. I eat roughly 180 grams of protein a day and 160 carbs with maybe 50 grams of fat. This is an approximation but I consume around 1900 calories a day. Using the HB method with an activity level I would say is around Moderate, according to my results I should be consuming 2700 calories a day. I have searched around the internet and this ranges from 1500 to 2000 on average. Am I misreading the results or am I at too much of a calorie deficit to get leaner? Thanks
@Kris – Not sure how you are getting to 2700 calories. My guess is you are maybe burning 2700 calories, but your intake could easily be around 1800. Generally speaking, for a guy who is 5’6” and 150lb, somewhere around 1600-1800 will help you get leaner. What I’ve found in my experience is people tend to overestimate the calories they burn. Also, HB for reasons I describe in the article is notorious for overestimating calorie burn.
When figuring out exercise how long are you talking about on a daily basis. I typically do Jillian michaels 3-5xweek which is 30 minutes long and is pretty intense. Or I do the elliptical for 1/2hr-1hr instead. I was thinking that is moderate exercise. Is that correct?
I think so. It’s not an exact science, but if you have a sedentary job and workout 3-5x per week, I was use a 1.45 activity multiplier, which is between 1.35 and 1.55. That’s actually the level I recommend for most people.
Hi marc have a few questions i am 34yr 5,6 155 pounds i have worked out sence i was about 19 my gym closed & i gained some weight and i have lost 20 so far but this last month i have not lost any my doctor put me on 1000 cal 3 months ago could that be the reason. I eat 5 or six times a day i try to eat only fresh food but i do have oatmeal 2 times a day is oats ok sometimes i eat special k is that a good choice or should i stay away from anything i didnt make fresh i feel like i dont know what else i can cut out of my diet i have really been so good on this diet for the last 4 months i bought me the home spinning bike &, i do spinning classes 3 to 5 days a week i work 12 hours on my feet walking all day is 1000 cal to little and is special k granola or oat meal a good breakfast i get home at 8:00 pm from work is that to late to eat dinner my goal is to get lean and i want to have a six pack is 125 a real goal for me my high school weight thanks for your advice.
Hey Mandy, let me see if I can separate out your questions:
Hi marc have a few questions i am 34yr 5,6 155 pounds i have worked out sence i was about 19 my gym closed & i gained some weight and i have lost 20 so far but this last month i have not lost any my doctor put me on 1000 cal 3 months ago could that be the reason?
My Answer: Probably not, but it could be. 1200-1400 is probably a better level. Make sure you are drinking plenty of water as hydration level can make a big difference in fat loss.
I eat 5 or six times a day i try to eat only fresh food but i do have oatmeal 2 times a day is oats ok sometimes i eat special k is that a good choice or should i stay away from anything i didnt make fresh
My Answer: Ideally fresh food is best, but I’m hardpressed to believe eating oatmeal a couple times per day is going to halt fat loss as long as you are eating less calories than you burn, which it sounds like you are. You may want to consider keeping your carbs at 100 grams, or less if you are carb sensitive.
i feel like i dont know what else i can cut out of my diet i have really been so good on this diet for the last 4 months i bought me the home spinning bike &, i do spinning classes 3 to 5 days a week i work 12 hours on my feet walking all day is 1000 cal to little and is special k granola or oat meal a good breakfast
My Answer: a couple eggs and a handful of fruit (or even yogurt) is a better breakfast than special K, I’m not a big fan of cereal. 1000 calories as I mentioned does sound a little low considering how active you are. Maybe even 1400-1500 calories could work well.
i get home at 8:00 pm from work is that to late to eat dinner my goal is to get lean and i want to have a six pack is 125 a real goal for me my high school weight thanks for your advice.
My Answer: It’s never too late to eat dinner. Anything is possible if you put your mind to it and your patient. You should shoot for around 1lb of fat loss max per week. Anything more and you may be losing muscle.
I’m thoroughly confused and hope you can help! I am a 30 year old, 5’3″, 142 lb woman. I am trying to get down to 128 (I lost 5 lbs last month). I also do a bootcamp in the park 4 days a week, so, according to the Harris Benedict method, my BMR is approximately 1429 at rest and 2216 with my physical activity. The past month, I have been eating 1300 calories a day, but I only lost 5 lbs. I don’t understand, because according to my calculations (2216-1300 is a deficit of 916 calories), I should have lost almost 10 lbs. What is going wrong? Should I never eat below 1429 calories (my BMR at rest)?
Thanks in advance!
@Natasha – Losing 5lb of fat (I hope it was all fat!) is a very solid pace of fat loss. You can lose 10lb in one day, but that’s not a very good idea because it will be mostly water, muscle, and some fat. As I mention, calculating your calorie burn exactly is not possible, so trying to play the “I burned this amount and ate this, so I should have lost x amount of fat” doesn’t work, because you don’t truly know how much you burned. It sounds like you are trending in the right direction, so keep up the good work! If you were losing any more than 1 to 1.5lb per week, I would say that’s actually a problem that’s undesirable.
aoa i m working in an iphone app in which i m using running,walking,jogging mode i m going to use GPS to track user’s distance covered ,duration of either walk , jogg,run etc pls tell me any recommended equation so that i can calculate calories burned by a person i think formula needs “weight” , “duration of exercise” “speed”, “distance covered” pls let me know about formula i m googling it but failed to get any good formula ……………………
@erum – There are a ton of different equations, but the only one I can remember off the top of my head is based on metabolic equivalents, or MET. You would have to figure out a way to express the activity and the speed in terms of MET. For example, running 6 minutes per mile has roughly a 16.3 MET whereas 10 minutes per mile is 10.2. You can look online for charts. The equation is (METS x 3.5 x body weight in kg)/200 = k/cal per minute
I just found all of your wonderful information. I am 5’3″, 154 lbs. My goal is to lose 15lbs. My BMR shows 1442 and with activity (1.375) is 1982.75. I have been on a 957 calorie diet and have not seen much improvement. I burn around 1200 calories a week in cardio. Should I increase my daily caloric intake? What percentage of Fat, Protein & Carbs are reasonable?
@KeeG – thanks for the kind words. I don’t know is the short answer. Sounds like you need to trouble shoot your calorie level. Somewhere around 1200-1300 calorie intake sounds more reasonable given your body size. Check out this post for protein/carbs/fat breadkdown – Best Macronutrient Distribution For Fat Loss? | Q&A Weekly Roundup
This makes no sense. I am 52, weigh 259 and am 6’5″. Supposedly my resting BMR is 2300. I exercise 1 to 3 times per week. I am here to tell you that if I even ate 2300 cals a day I would weight 400 lbs by the time next year.
How the heck can these numbers be right? I know from 52 years of eating experience that 2300 cals a day is WAY WAY WAY too much for me to lose weight. With my exercise level I am supposed to be able to wolf down 2100 calories a day and still lose 2 lbs a week.
I am here to tell you, there is no way. I’ve eaten that much before. I get FAT.
@Bill Mitchell – I need to write an in depth article on metabolism/genetics because some people have lower metabolisms than others. It does sound very surprising to me that you would be unable to lose weight on a 2000 calorie diet, but it sounds like you know your body. You may consider getting your BMR checked out (there are machines that measure BMR as I showed in the article) and consulting a nutritionist to see what he/she has to say.
Ugh. All I can say is ugh.
I have tried everything. I’ve cut out all processed carbs, cut out all diet soda, cut out cereal. I am seesawing my calories between 1800 and 1400 a day. I am taking a 1/2 hour walk every day.
I have now weighed exactly 259 for 10 days! WTH? I was especially good yesterday. Ate only lean meat and vegetables. Had plenty to eat and came in around 1350 calories. Wasn’t hungry at all. Had been excited because I had finally broken below 259 the other day to 258. This is it finally! I thought.
But this morning back to 259! Seriously, I am a 6’5″, 259 lbs (large frame – I look slim in clothes at this weight – just a little soft shirtless but by no means fat), how do I GAIN a pound on 1300 calories? My BMR just breathing is 2000 calories a day.
It is as I am somehow defying the laws of thermodynamics.
The weird part is that I went from 269 to 259 just like that, But for some bizarre reason, 259 is a steel plated, kevlar coated kyptonite drenched wall of concrete. I have now been on a great diet plan for 10 days and have not lost 1 single ounce. My metabolism is clearly completely dead (and yet I feel fine).
@Bill – It’s only been 10 days, so I would consider 20+ days as a plateau. Could be water, sodium, glycogen etc. that could keep your weight a little higher. I would recommend taking a longer term outlook toward reaching your fitness goals. Maybe create short term goals of losing 1-2lb per week, and longer term goals as well. The point is that losing weight and changing your body is a marathon, not a sprint. Finally, if you haven’t checked out my free Get Lean Guide, I would check that out if I were you. The exercise portion may be particularly helpful. In my experience the magic happens when you have a great nutrition plan AND a great exercise plan.
Thanks. I think part of the problem may be that I am a colon cancer survivor and ever since then (4 years ago), my testosterone has been very very low (like a reading of 65 or something). Most me my age are around 350 I think.
The doctors cannot figure out why my testosterone is so low. The testes seem to be working fine. They believe that for some reason, the gland that tells the testes to make testosterone isn’t sending the signal.
However, I do not have any signs of low testosterone. I am energetic (for a 52 year old) and have no sexual dysfunction at all. I grow a normal beard (have to shave daily) and have a rather deep male voice. I “look” in the picture of health.
I don’t know, it is all quite weird. This is what I ate today:
Raisin Bran with Splenda
Baked pork chop
Cucumber salad with light balsamic dressing
About 5 glasses water.
No soda, no processed carbs.
About 1300 calories but ate PLENTY – 3 full meals and 2 snacks. This is how I eat every day but lose no weight.
@Bill – I really need to revise the calorie post because there is more to losing fat than just eating less calories. As you are experiencing, hormones can have a huge impact. my best guess is your low testosterone level is seriously affecting your ability to lose fat. I have a large article database with articles that we plan to write and testosterone is a topic we plan on covering in depth, but at this time it has not been written. With that said, I would consider natural ways of helping increase your testosterone to see if that helps. One more thing, I would consider eating eggs in general instead of dairy/grains in the morning. I used to eat dairy/grains for years in the morning, until i finally realized it was wreaking havoc on my digestion. Also has a pretty huge affect on insulin as well. You should certainly consider talking to your doctor about testosterone, as well as a naturopathic physician and compare what they say.
Calorie wise people would say I’m in “starvation mode” but I hardly think eating 3 full meals and 2 snacks is starving. I was stuffed after every meal.
The sad part is I am still 45 pounds from my goal weight. Is it going to take me a month of dieting to just lose a pound at a time only to have it reappear for no reason out of the blue? Is this the body I get from now on no matter what?
And before anyone says “maybe you are in starvation mode”, I’m not. I’m not hungry. I am eating lots. If you cut out bread and starches and dairy from your diet, 1500 calories is a A LOT of food (for instance, that’s about 15 chicken breasts – who could say someone eating 15 chicken breasts a day was “starving”?)
My meals are healthy, well balanced, drinking plenty of water, no soda, getting exercise.
How, seriously how?
can you help me , am 41, 5 foot 3 inches, 160 lbs, moderate exercise, how many calories should i eat to loose weight?
@dee – please see our how How Many Calories Should You Eat To Lose Weight? post.
Mark. Thanks for the great site an all the info. I am back on by weight loss journey once again. I have gained and loss weight for the past 10 years. I’ve gone from lowest of 185 to the highest of 260. I know that I know, when I am eating clean, eating under 2000 calories is very doable. If I work out 3 to 5 times a week, I can slowly lost weight. However, based on these numbers and my high weight at the moment, I am supposed to be eating 2500 calories. I just can’t wrap my mind around that. I really think that extremes of up and down dieting have fried my metabolism. What is the worse that can happen if I stick to around 1800 calories and work out about 5 times a week? Workouts would be a couple of 2.5 mile runs and about 3 lifting sessions. I always take a good amount of protein after workouts.
@Jamie – I need to update my “How Many Calories Should You Eat To Lose Weight” post, because individuals who have more fat to lose can get away with more aggressive low calories diets than those who are already getting leaner. So 1800 calories should work fine. Of course, yoyo exercising/eating is a major issue, so I hope that as you lose the weight this time it will be more manageable for you!
Hi there ! Thanks so much for the informative articles.
I am a 20 year 5 ft 10 old female, I did weigh 260lb in May this year but have managed to get myself down to 210 so far from calorie counting and exercise 3-4 days a week.
I made a bas mistake when I first started though of only eating 800 a day on top of exercising and I have a very active job as well where I am on my feet doing hard cleaning for 4 hours a day, and my weight loss stalled and I actually put on weight.
I looked more into BMR and so on after this and didnt realise you had to eat at least your bmr to lose weight.
Anyway what Im saying is I wanna accurately work out what I need to eat and how much. I worked out using the Harris Benedict method my BMR is 1803 for my sex and height, and as I exercise 5 days a week now as well as having an active job I put my activity multiplyer as moderate and added my bmr into it and it came out as 2794.
So I was just wondering, is this the amount I have to eat per day in order to healthily lose weight ?? It just seems very high to me, Im currently eating around 1500 and a little extra depending how many calories I burn off through exercise (usually burn about 800 a day from exercise) so I eat an extra 800 on top of 1500.
I just wanted to clear it up and make sure I am doing it right 🙂 Im a little confused as to 2794 is how many I should be eating.
Thanks in advance !!
@Jemma Benns – I need to update the how many calories should you eat to lose weight post, but I think for those people who have a good 30lb+ to lose, eating less calories than BMR is absolutely ok. It’s not a hard and fast rule. The idea is still to get the proper nutrients you need (vitamins and minerals) even with less food while not getting too hungry so you can sustain the diet. Good luck!
QUESTION: I’m a metrics person and wanted to know “WHAT ABOUT THE OTHER 10%?” (the article starts out noting 65%+20%+10% as the 3 ways burn occurs but it’s short by 10%… is there actually a 4th way it burns or are these 3 percents off?
What’s up, yeah this piece of writing is genuinely nice and I have learned lot of things from it on the topic of blogging. thanks.
Glad to hear it, Robt! Our goal is to educate, so we’re stoked to hear you’re gaining value from our articles.
-Kristin, BuiltLean Coach & Managing Editor