IBF Heavyweight Champion and newly-crowned poster boy of British
Joshua is well-known for his power, incredible fitness levels and generally being a mild-mannered and bloody nice bloke.
A couple of days after his defeat of Klitschko I started seeing some content about his diet doing the rounds in the media (ok, on Facebook), with many claiming that he was eating 4,500-5,000 calories per day in the lead-up to the fight.
It got me thinking, that doesn’t really sound like much for a 6ft 6 guy weighing in at 113Kg, carrying slabs of muscle and (from what I’ve seen/read) smashing in the most intense training schedule for several hours each day in the lead-up to the fight.
I can quite happily maintain my weight (82Kg) on 3,000 calories per day doing a bit of walking around and lifting some weights 4-5 days a week.
So, being the geek I am I thought I’d drill down into the numbers.
First of all, let’s take a look at how many calories Josh burns per day.
N.B. I’m taking these figures from the Mail’s article (they all quote slightly different amounts).
One more thing before we dive into the analysis.
Below is a graph which shows the four different elements that contribute to our TDEE (total daily energy expenditure).
The ratios will be different for every individual based on different factors such as activity level, diet composition, age, gender, lifestyle etc but for almost everyone, BMR (base metabolic rate – a number of calories required every day just to keep you alive) will be the biggest contributor to TDEE.
BMR. or base metabolic rate is the number of calories individual burns at rest over the course of a day.
‘At rest’ literally, means laying/sitting down all day doing NOTHING (which pretty much sums up my perfect weekend).
Using the Harris-Benedict equation, Joshua’s BMR comes out at;
This is probably a bit lower than the genuine figure because lean body mass (to the amount of muscle an individual carries in relation to fat) affects BMR (the higher your lean body mass is, the higher your BMR will be).
For the purposes of this article, I’m going to add another 10% onto this figure to account for Joshua’s lean body mass, this gives us;
Neat stands for Non-Exercise Activity Thermogenesis.
This is the calories burned through low-level activity such as walking.
Let’s say Joshua, walks 5 miles per day (which is about 10,000 steps per day).
Walking 1mile burns approximately 100 calories for the average person, which makes 500 calories.
Again, because of Joshua’s weight and muscle mass, I’m going to add another 10% to this (which is probably very conservative), that gives us
During his training camp (98 days before hos fight) Joshua will arguably contend with one of the most intense training schedules of any sportsperson in the world. which means the amount of calories he’ll burn during his exercise sessions will be immense.
I’m going to use the following figures as a guideline for working out Joshua’s calorie expenditure through exercise.
Joshua allegedly ran 210 miles over the course of his 98 day training camp. This averages out at 2 miles per day.
I used the Under Armour calculator to work out that he’d burn 331 calories running at a pretty conservative pace of 15 minutes per mile – or 4mph (this pace would have likely varied wildly but 4mph seems like a fair average).
Joshua cycled 217 miles over his 98 camp, this equates to 2.2 miles per day.
I used the same calculator to arrive at a figure of 181 calories burned at a pace of 13mph, which is pretty slow really, but again let’s take it as a conservative average.
660 Rounds over the course of 98 days averages out at 6.7 rounds per day.
Each round is 3 minutes, so 3 x 6.7 = 20 minutes.
Again, the Under Armour calculator gives us a total of 243 calories.
The amount of calories you burn lifting weights is notoriously difficult to work out (if you’ll excuse the pun), unless you’re wearing a heart rate monitor.
Unfortunately, I don’t have access to Joshua’s data, the Daily Mail (rolling eye emoji) claims that he trains for 4.5 hours per day. I’m assuming that this is just resistance work and excludes his running, cycling and sparring.
The amount of calories he’ll burn really depends on what he’s doing. He’ll burn WAY more calories doinf deadlifts and squats than he will doing bicep curls for example, but I’m just going to have a shot in the dark and say he’ll go through 1,000 calories over 4.5 hours of resistance work. This is probably REALLY conservative.
Totting all that up, I’d estimate that Joshua burns 1,755 calories through exercise
Thermogenic Effect of Food
The thermic effect of food is how many calories our body uses digesting food.
The energy used digesting a given food will depend on the macronutrient ratio.
Protein requires the most energy to digest, followed by carbs and then fat. Here’s the amount of energy required to digest each macronutrient;
This means that if you ate 1000 calories worth of protein, 300 of those calories will be expended just digesting that food.
N.B. These are rough figures, the exact amounts are up for debate, and I have to confess I got these from Bodybuilding.com rather than a credible, scientific source which I’m really embarrassed about. I need better references.
Anyway, in order to calculate how many calories Joshua might burn just through digesting food, I’ve taken the supposed ‘4500 calorie’ figure quoted as his daily intake and split that up into what I believe would be an ideal macronutrient ratio for him.
If you want to know more about why I think this is a good macro split for him, get in touch.
So to work out the thermogenic effect of each macronutrient, we first need to work out how many calories of protein fat and carbs he’s eating.
Based on the above assumption, this would be;
Protein: 1,124 calories
Carbs: 2,476 calories
Fat: 900 calories
Next, we need to work out what percentages of those macronutrients would be burned via thermogenesis.
Based on my (potentially ropey) figures from Bodybuilding.com this gives us;
Protein: 337 calories
Carbs: 248 calories
Fat: 45 calories
This gives us a total of 630 burned via thermogenesis
Time to total everything up.
If we now add up all the figures from the different sources of calorie expenditure, this should give us a rough idea of Joshua’s TDEE (Total Daily Energy Expenditure).
BMR: 2,666 calories
NEAT: 560 calories
Formal Exercise: 1,755 calories
Thermogenic Effect of Food: 630 calories
After all that we have a grand total of (drumroll);
5,611 calories per day
Now, remember that this is probably quite a conservative estimate. I would imagine that Joshua’s BMR is a bit higher than the figure I arrived at, owing to his very favourable body composition. I would also suggest that AJ would burn way more than 1,000 calories during his 4.5 hour resistance session (although this would be highly dependent on the intensity of the sessions).
In reality, this is just a guess, but when my FitBit tells me I burn an average of over 3,000 calories per day when I’m essentially desk-bound for 8 hours and weighing in at 82kg (and I have very good reason to believe this is accurate) I can certainly believe AJ would easily steam through five and half thousand calories a day.
So what gives?
Well, one of two things.
- Joshua’s TDEE wasn’t this high every day because he didn’t do 4.5 hours of resistance training every day. I could speculate on where he did or he didn’t (4.5 of resistance training for 98 consecutive days does seem hellishly gruelling even for a heavyweight champ).
- Joshua’s nutritionist set up this diet for him to lose weight throughout the course of the training camp. If he was burning 5,611 calories a day, here’s how much much weight he’d be losing.
If he ate 4,500 calories per day: 0.5kg every 3 days (over 1kg a week)
If he ate 5,000 calories per day: 0.5kg every 6 days (just over 0.5kg a week)
3. The media got their wires crossed and were totally wrong about his activity, or his calorie consumption (or both). If his goal was to main weight throughout the training camp, his calories would have needed to be closer to 5,600 per day.
4. I’m an idiot and my calculations are all wrong.
If you’d like me to help you calculate your TDEE, and the amount of calories you need to be consuming to either lose body fat or gain muscle, then get in touch.
I can’t help you KO Wladimir Klitchsko though, sorry.
Joe is an online weight loss coach and qualified personal trainer of 15 years who helps busy, professional men and women lose fat and build muscle.
Having a 9-5 desk-job, Joe understands the struggles of juggling a hectic life with trying to maintain a good physique.