This video explains the distribution of maintenance calories, and give you some insight into why it’s actually not that simply to answer the questions ‘How many calories do I burn a day?’.
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If you’re interested in losing weight, the single most useful piece of information you can know is how many calories you burn in a day, also known as your maintenance calories or ‘total daily energy expenditure’ (TDEE).
This number helps you plan your deficit, which is key to weight loss. So if you burn 3,000, you can safely say 2,300 is a solid starting target. If you use 2,000, then 1,500 is a better option.
If you go to an online calorie calculator, enter gender, age, weight, height and activity level, it will give you a detailed estimate like:
2,891!!
Correct to nearest calorie, this number looks precise. It comes from a calculator branded ‘highly accurate’ and ‘scientific’. So it’s completely natural for me to trust it. After all humans are wired to trust precise numbers.
But there’s a problem. This calculator is built on an inaccurate estimate multiplied by a dodgy guess (the activity multiplier). This result could be off by 500 calories in either direction. So even if I nail my diet, I may end up seeing little to no results.
To add some detail to the video I’ll explain:
- The Maintenance Calories of Men and Women
- Four Reasons Our Energy Needs Vary
- Two Fatal Flaws of Calorie Calculators
- Calorie Targets for Men and Women
- How to Find What Works for You
1. Maintenance Calories: How Many Calories Do Men & Women Burn
You may have heard that the average woman burns 2,000 calories, or that a man burns 2,500 calories. These numbers are well intentioned catch all figures for public health policy, but they’re misleading. Modern Americans have calorie needs that are distributed in bell shaped distributions around 2,400 calories for women and 3,100 for men.
We can see this using data from the Institute of Medicine’s Dietary Reference Intakes.
How many calories do women burn?
Here’s the distribution for 382 women:
Here’s a quick summary
- 20% burn less than 2,000 calories a day (low needs)
- 65% need 2,000-2,800 calories (average needs)
- 16% burn more than 2,800 calories a day (high needs)
- the median woman in this sample burns 2,365 calories
What about the men I hear you ask? Good question.
How many calories do men burn?
The calorie needs of men are also distributed in a bell shape. But men have more muscle, less fat and larger organs (liver, kidneys, heart) at similar bodyweights to women. So they have higher metabolic rates.
Here’s what the distribution of the 264 men in the sample looks like.
Here’s the cliff notes:
- 19% burn less than 2,600 calories a day (low needs)
- 59% need between 2,600 and 3,800 calories (average needs)
- 20% burn more than 3,800 calories a day (high needs)
- the median man burns 3,076 calories
I’m not going to dwell on these figures, because at this point I realise everyone is asking ‘where on this chart am I?’.
This is a tough question. But understanding why calorie needs vary can help.
Bottom line: Energy needs have a bell shaped distribution
2. Four Reasons Calorie Burn Varies
There are lots of genetic and behavioural reasons why our calorie burn varies which are hard to pin down. But there are a few things we can explain with evidence. Specifically age, height, weight and activity level.
Let me show you with some visuals.
Young people burn more calories
It’s not crystal clear why, but energy needs decline as we age. Some of this is lost muscle mass, some changing lifestyle and some seems to be things changing at a cellular level too. Whatever the reason you can see it clearly in the data.
The orange dots are the data for 381 women. The black dots are 264 men. And the ‘lines of best fit’ act as a rough average. Although you can see the variation is huge age is only explaining 10-20% of this.
Average needs for women drop from 2,700 calories at age 20 down towards 2,000 at age 70. While for men they begin way up near 3,400 at 20 and fall to 2,800 by 70 (which seems surprisingly high).
Tall people burn more calories
Tall people burn more energy than shorter people. Part of this is simply having more surface area to dissipate heat. But they are also likely to weigh more and have bigger organs. Here’s the correlation.
Virtually all the women with low energy needs (below 2,000) are shorter than 170cm (5’7). You can also see from the black dots the high energy need men (above 4,000) are often up around the 6ft mark.
Heavy people burn more calories
Heavier people generally have higher metabolic rates. This reflects the fact that more energy is required to move a larger body and their bigger muscles and organs. Here’s how the data looks for weight:
Even for the same weight men typically have an energy expenditure that is 500 calories higher than women, due to less fat, more muscle and larger organs.
Light women (around 110lbs) average just 2,200 whereas 100kg (220lbs) women can expect to use 2,800. The effect of weight on energy needs is even greater in men. 100kg (220lbs) men regularly clock in around 3,500 calories a day.
Active people burn more calories
Activity level is derived from dividing someone’s total energy use by their basal metabolic rate. Fitness websites often equate activity level with how much exercise you do, but this is just part of it. Your activity level reflects genetics, work life, exercise patterns, muscle mass, postural control, propensity to fidget . . .
Here’s what the correlation looks like between energy needs and activity level.
Activity level is a stronger explainer of energy needs than age, height or weight. In this data set it explains 40-50% of the variation. If you’ve ever known one of those people that just doesn’t seem to put weight on regardless of what they eat you’ll probably find they are a world class fidgeter. Other things that drive up activity levels are physically active jobs (think manual labourer) and endurance training (think triathlete).
If you’ve looked at that graph and wondered how on earth do you know what your activity level is, you have just discovered why you should never take the result of a calorie calculator that seriously.
Bottom line: Activity level, weight, height and age affect energy needs
3. Two Fatal Flaws of Calorie Calculators
Calorie calculators should all come with disclaimers about how potentially inaccurate they are. In this section we’ll talk about two reasons you should always view their results skeptically.
Activity levels are tough to estimate
The primary reason you should never trust a calorie calculator, or any weight loss calculator for that matter, has to do with their simplistic treatment of activity level. Almost all calculators estimate your resting metabolism (which already has a degree of variability ±20%), and then multiply it by an activity multiplier based on exercise levels (typically 1.2, 1.375, 1.55, 1.725, 1.9).
Getting these multipliers right is very hard. And pretending they are determined largely by exercise is plain false. Let me show you some data to make this point.
Here’s what physical activity level looks like when graphed against age.
The standard range of 1.2-1.9 doesn’t even capture a huge share of this sample. And many weight loss calculators have taken to using their own lower ranges (1.1-1.6) that have no basis in real data.
In this chart average physical activity level (PAL) is 1.7, so is the median. Over 80% of people fall somewhere between 1.4 and 2.1. The things likely to take a person above 2 are a physically active job, endurance training or being one of those lucky fidgety folk that are wired to burn excess food. Going below 1.5 is likely to involve a desk job and is much more common in older people.
The reality is you can’t estimate your activity level with any accuracy without laboratory testing. So when a calorie calculator asks if you have a ‘sedentary’, ‘moderate’ or ‘active’ lifestyle the alarms bells should ring!!
Your calorie needs change over time
The second reason you can’t put too much stock in a calculator is that your energy needs change over time. During a diet your body will actively defend its fat mass by reducing energy use and increasing hunger signals. This is your hormonal defence system telling your brain (the hypothalamus primarily) to protect itself from losing too much weight.
Let me give you a concrete example. The graph below comes from a great free living study that looked at how people adapt to caloric restriction. Here’s what the average adaptation of people that started on a 25% deficit looked like after three months in that study.
These people lost 6kg (13lbs) in 3 months. At the start of the diet the deficit averaged 712 calories but by the end it had dwindled to just 258. The downward adaption was largely due to the decline in spontaneous activity (NEAT).
So in the process of losing just 6kg the average drop in calories burned was a whopping 450 calories a day!! That’s a 17% drop in their daily calorie burn.
Bottom line: Our calorie needs are varied and adapt over time
4. Calorie Targets for Men and Women
Seeing the four graphs earlier in this article for age, height, weight and activity should hopefully have given you a vague idea of your own energy needs. Even if its just a broad range.
To set up a solid calorie target for fat loss you need to apply a deficit to your needs. Because I have no idea where you sit on those bell curves I’m going to set a deficit for the whole distribution.
If you are going to carefully track your food (with a food scale) at 15-20% deficit is good. But because most of our readers are regular people, rather than physique athletes, let’s go for a more aggressive 25% deficit. This should bring the vast majority of our sample to 500-1,000 calories below their needs. In line with the National Institutes of Health (NIH) guidelines and big enough to allow some inevitable slip ups.
Starting targets for women
Here’s our female distribution after the 25% deficit has been applied.
Ok, here’s what we can see.
- low energy needs: target range 1,200-1,500 calories
- average energy needs: target range 1,500-2,100 calories
- high energy needs: target range +2,100 calories
The average needs women fall into a 1,500-2,100 calorie target range. This is their starting target. Scale weight may well end up telling them they need to be more aggressive, particularly women with desk jobs. Women with low energy needs will be forced to eat 1,200-1,500 to shift fat adequately. While high burners can lose well at +2,100.
I’ve shaded all the figures below 1,400 calories in orange because because these targets deserve some caution. In this sample 1,400 calorie figure does not meet the resting metabolism needs of 40% of this sample. Although it is well above the NIH safety floor of 1,200 calories for women.
Calorie targets for men
Here’s our male distribution after the 25% deficit has been applied.
Here’s what we can see for men:
- low energy needs: target range 1,600-2,000 calories
- average energy needs: target range 2,000-2,700 calories
- high energy needs: target range +2,700 calories
The bulk of our men fall into a 2,000-2,700 calorie range. Again if you’ve got a desk job don’t be surprised if you end up down around 2,000 calories relatively quickly. Some lucky guys will do well at +2,700 while those will low needs will need to jump straight in below 2,000
I’ve shaded all the figures below 1,800 calories in orange because this figure doesn’t meet the resting metabolic needs of 43% of this sample. Although once again this is well above the NIH safety floor of 1,500 calories for men.
Just to recap! These figures are only designed to give you an idea of where to start. I don’t want to give you the wrong idea that women can all get shredded on 1,800 calories or men at 2,400. That’s just not how it works sadly. At the same time the idea that all women should be jumping straight in at 1,200 calories is equally as absurd.
Bottom line: A 25% deficit is an aggressive starting target
5. How to Find What Works for You?
Ok. let’s try and make this a little more real.
The ‘average women’ in our sample is 43 years old, is 5ft5 (1.64m), weighs 153lbs (70kg) and needs almost 2,400 calories a day to maintain her weight. She can expect to lose over a pound a week starting at 1,800 calories (our 25% deficit), then gradually adjust to 1,700, 1,600 and 1,500 a day to keep things moving over time.
Will these numbers work for you? I have no idea. But I can show you how to find out in two steps.
1. Set a sensible starting target
I’m going to do these examples for women, because frankly it’s just a lot harder for women. Let’s start with an 1,800 calorie target, for a typical woman, and make a few adjustments.
- Age: < 30 (+100), 30-50 (0), > 50 (-100)
- Weight: <140lbs (-200), 140-180 (0), >180lbs (+200)
- Job: deskjob (-300), varied (0), active (+300)
Let’s do three examples
Jenny is 25, 170 lbs and an architect: 1,800 + 100 + 0 – 300 = 1,600
Ruth is 35, 160 lbs and a gardener: 1,800 +0 +0 + 300 = 2,100
Karen is 58, 130lbs and an accountant: 1,800 -100 – 200 – 300 = 1,200
Is this calculation perfect? No!! All calculations are estimates. This is a ‘starting target’ that could easily be out by a few hundred calories. That’s why we have to test it!!
Note: Men can you can use a similar estimation but start with 2,400 instead of 1,800.
2. Test if this target works for you
The second, and more important step is to test how this target works for you. Here’s a simple four step formula:
- Eat as consistently as you can for 5 weeks
- Weight yourself for these 5 weeks
- Calculate the average rate of loss from week 1-5
- Adjust your target to hit 0.5-1% loss per week
Let’s take Jenny. For six days a week she tries her best to hit 1,600 calories (Saturday is off). She weighs herself each weekday morning, and calculates the weekly average from these. She ignores the first week’s result (misleading water weight losses).
After 5 weeks the results are in. If her average bodyweight change in weeks 2-5 is 1lbs/week (0.6%) her target is awesome, she’ll keep that up till things slow. If she’s losing 2lbs/week (1.2%) she’ll add calories back, perhaps up to 1,800. If she’s only managed 0.5lbs/week (0.3%) she’ll drop calories to say 1,400.
In each scenario Jenny has succeeded in testing if her target works! Sure she had to work hard at it for five weeks, but in each scenario she know exactly what to do next. She can move on to focusing on how well she hits her target.
Now here’s the really interesting thing!!
You don’t necessarily need to count calories to use this technique. If over a month you are losing weight at a healthy rate (0.5-1% of body weight per week), your calories are solid!! It doesn’t matter if you’re tracking calories or macros. Eating paleo or vegan. Doing intermittent fasting or six meals. You in a deficit! You want to ride that phase out till the wheels fall off 😉
The key ingredient is consistency!!
Bodybuilders have been getting shredded like this for decades. They eat a consistent diet (by counting macros), track their results (morning weigh ins) and adjust to progress (100 calorie cuts from carbs or fats when things slow).
Simple to explain, but not easy to do.
Bottom line: You can test your target with consistent eating
How Many Calories Do I Burn?
Here’s what we learnt:
- Energy needs have a bell shaped distribution
- Age, height, weight and activity level affect our needs
- Calorie calculators are inaccurate guesses at best
- 1,500-2,100 is a good weight loss target for most women
- You can test your target by eating consistently for 5 weeks
For ideas on creating a deficit in style check out 5 Simple Strategies
