Why 1000kcal workouts are BS: Why you shouldn't be concerned with calories burned in a session

The following is an excerpt from my weekly newsletter that you can subscribe to by clicking HERE

The burpees made a return the classes this week after I was left heartbroken on Tuesday morning, watching the highlights of the 49ers lose with the last kick of the game.

I won't bore you with the details, but it did have a domino effect for the day and led into this newsletter's topic. After my HIIT session in town that afternoon, which included burpees, I was asked how many calories do I reckon was burned. Truthfully, I did not know. There are too many variables I told him. For example, the work rate in the session, heart rate, age, gender, weight to name but a few. 

But on average, how much? I was asked. And I hate "b.s.ing" people. So I said there's too broad a range that giving a figure would not be helpful. And it wouldn't. 

How many calories do you burn in a session?
Let's take a spin class for a second. In a spin class, people say you burn anywhere from 400kcal to 600kcal an hour. And if you have ever been in a spin class, you know everyone is not bringing the same intensity to the session. So there's going to be a big difference in calories burned. Some are pretending to up the resistance on the bike, some haven't the energy to keep going etc. The difference is going to be huge. 

And then you have those that claim x class or type of training will burn more calories. One of the types, HIIT training, has an estimated 900 to 1000 calories an hour. Ok, that's a considerable difference to spinning. But, once again, the intensity of the exercises has to be called into question. If you can go full throttle, 100% as hard as you can, on every high-intensity exercise for an hour, with a minimal break? You are an actual machine. It's not possible. Realistically, there need to be parts of the exercise where you need to slow down and restore your energy levels before going again.

So while on paper, you would burn 1000 calories, realistically you won't get close to it. 

Also, jump rope burning 600-800 calories an hour? Are you really going to skip for an hour?

And there lies the problem, in my opinion. What I assume is happening here is that the hardest part of a HIIT session is being recorded for calories burned over the hardest 5 minutes. And then they are using that number as an average for the hour. That 5-minute intensity is not the same output for the entire hour. It's misleading marketing as you won't be able to maintain that intensity over an over.

Here's an article on how to burn 1000 calories in an hour. One of them is through sprinting. 30 seconds of sprinting... you can run fast, but you can not sprint for 30 seconds. And sure definitely can't repeat it for an hour. That is an injury waiting to happen. 

It slow periods in between a session, you can get up to 45 minutes of a great workout in. If it is spaced and organised right. After that, you run a risk of injury, and you still won't get near 1000 kcal burned in an hour. 

Why working out longer doesn't mean you are burning more calories.
Intensity, rather than time, matters more for a session. The longer you train at a really high intensity, the more likely you are to suffer an injury. 

Also, let's look at the estimated calories burned when I did the marathon this year and my disastrous first year:

Even though I was an extra hour on my feet on the course (a horrible day at the office), I burned fewer calories. This shows that time is not the main factor in burning calories.

Why fitness trackers are bad for counting calories. 
If you look at the calories burned in both marathons, they are over the 3,500 mark. Of course, neither included my heart rate. But I recorded the run this year on my FitBit. According to my FitBit this year, I burned 3,600 calories.

Only 100kcal difference to the Nike Run App over a 4 hour training period would lead you to believe that they are both accurate. However, it is estimated that you burn roughly 100 calories per mile for a marathon. That's a little over 2,600 for an entire race. 

There's a 1000kcal difference in the results there. Going from 3,600 kcal to 2,600kcal is a 27% decrease (honours maths yet can't count in a PT session!). Which is ironic as Stanford University did a study showing that the most accurate energy expenditure tracker is off by 27%. With other trackers but until 93%. 

What's the point in all of this, Seán?
Fitbit and other trackers can be great motivational tools. But when it comes to training, never assume calories burned number is accurate either through them, Apps, or what any promotional material tells you. If any type of class says you will burn 1,000kcal in a one-hour session, it's simply not true.

There are way too many variables to count calories being burned in a session. You can't accurately rely on them for how many calories you can afford to eat and maintain a calorie deficit. That is if your goal is fat loss.

So what do you do?
Stop overcomplicating your training with worrying about calories being burned. A tough 45-minute session is enough for most of us. Some sessions will feel better than others. Sometimes you will lift a little heavier, go a bit faster. Other times it will be roughly the same as the previous session, and that's ok too. Every session can't be the best session ever. But the main number you should be concerned with is the number of sessions a week. Not the amount of sessions but the consistency. Working out 5 days one week is excellent. But not if you get no sessions done the following week. Staying consistent 3-4 times a week and monitoring your progress will help you see results.

Calories in vs Calories out matter. But it is complicated to monitor calories out so focus on calories in by planning your meals and staying consistent. I did a podcast on this earlier this week on my top 7 tips to avoid overeating that you can check out below (along with talking about why 'Toning" muscles is not a thing).

You can check out the Coach Seán Fitness Podcast on Apple Podcasts by clicking HERE. 

Or on Spotify by clicking HERE

Stay consistent with your training. Make it sustainable each and every week yet challenging.