Can you really cancel out a day of junk food simply by exercising harder?
It’s a question that’s sparked endless debate among fitness enthusiasts, athletes and nutrition experts alike. Most would argue the answer is a firm no, but World’s Strongest Man Mitchell Hooper decided to put the theory to the test in spectacular fashion by attempting to consume and burn 10,000 calories in a single day.
Rather than relying solely on a fitness tracker, Hooper combined his resting metabolic rate with estimates from his activity throughout the day to calculate his total energy expenditure, hoping to see just how close he could get to breaking even after an enormous fast-food feast.
Introducing the challenge, Hooper admitted he wasn’t convinced that eating would be the difficult part.
“Most people say no, but today I’m going to do my best,” he said. “I’m going to eat 10,000 calories, and I’m trying to burn 10,000 calories in the same day. This might be one of the hardest things I’ve ever tried. I don’t think the food’s going to be a problem, but am I able to move enough, between maintaining my body, my cardio, my strength work, recreation that we’re throwing in between, can I burn 10,000 calories? We’ll find out.”
His day began with a calorie-heavy breakfast that included Peanut Butter Oreos, pastries and bread, bringing his first meal to around 1,500 calories.
After a delayed start because of work commitments, Hooper headed out on foot before making his first fast-food stop of the day.
“You cannot eat 10,000 calories a day without one Costco glizzy,” he joked after picking up Costco’s famous hot dog, naturally accompanied by a Diet Coke rather than a sugary soft drink.
Despite the challenge, Hooper couldn’t bring himself to switch drinks.
“Even on a 10,000 calorie day, I just can’t bring myself to do anything other than Diet Coke.”
The hot dog also prompted an amusing philosophical debate.
“Something does make me wonder, though, about the total net health effect of a Costco hot dog,” he said. “Sure, it’s not good for you in terms of food, but it’s so good for you in terms of your soul. I feel like it could sort of cancel each other out.”
From there, Hooper squeezed in more walking before briefly interrupting the challenge for a scan on his knee.
Lunch came courtesy of McDonald’s, where he tucked into 20 Chicken McNuggets alongside a Quarter Pounder.
The order wasn’t quite what he’d hoped for.
“This is diabolical,” he laughed. “First of all, quarter pounder with cheese, no cheese. I did not want only mustard. I wanted only ketchup and cheese. If you get only mustard, you are a lunatic.”
With more than 3,000 calories already consumed, the focus shifted firmly towards burning energy.
Hooper spent time playing basketball before heading into the gym for a lengthy resistance training session.
Although the workout was demanding, he admitted lifting weights wasn’t particularly effective if the goal is simply burning calories.
“Workout done,” he said. “We got stuck into lat pull-down, a whole bunch of different rows, bicep circuit, and during that workout, I burned about 180 calories.”
He continued: “Volume was higher than I’m used to for sure. I think it’s probably being underestimated by the watch. But the principle remains true. Strength training and lifting weights is absolutely not the way to burn calories.”
He also stressed that calorie burning alone shouldn’t be someone’s primary objective when trying to lose weight.
Cardio, however, remained a necessary part of the challenge, even if Hooper admitted he wasn’t enjoying it.
“Problem with cardio is just so boring,” he said. “I’ve run a marathon. I’ve run three marathons. I know the process of chasing a 5k PB and flying down the road, and lifting weights is way better. I promise you.”
As the day progressed, another huge meal awaited him at Raising Cane’s, with approximately 2,500 calories sitting in front of him.
Looking at the mountain of food, Hooper was surprised by how manageable it appeared.
“This is 2,500 calories. It doesn’t seem like a lot, and it’s really not. You can stack in calories quick.”
By this stage, however, he had begun questioning the numbers being displayed on his Apple Watch.
“My Apple Watch right now has me at 1,700 calories,” he explained. “And that’s a problem. Problem one is there’s no way I’m going to hit 10,000 calories of expenditure.
“But the bigger problem is there’s no way that that’s accurate.”
Hooper believed wearables could significantly underestimate calorie expenditure for someone of his size and activity level.
“At 330 lb with 14,000 steps, 35 floors climbed, a 90-minute resistance training workout, I realise this seems to be way off.”
Using alternative calculations, he estimated he had already burned around 7,000 calories rather than the 1,700 displayed on his watch.
He explained why accurate energy expenditure matters.
“If I do, my body will have expended 10,000 calories and consumed 10,000 calories. I will literally be a net zero for the day,” he said. “If I did that for an entire year, I’d be eating fast food all day, 10,000 calories, and gain zero lbs at all.
“It goes to show, especially if you’re a different size, using expenditure strictly from a wearable can be a pretty inconsistent result.”
The evening brought another stop at one of Hooper’s favourite restaurants.
“Olive Garden is my favourite spot for a nostalgic reason that I’ll explain at a later date,” he said.
As always, it came with another Diet Coke, which received glowing praise.
“Olive Garden gets Diet Coke right more often than anyone else on the face of the earth in terms of quality, never running out of syrup, and providing refills in a very timely manner.”
After partially finishing his meal, Hooper picked up one final dessert for later in the evening — a large vanilla shake loaded with peanut butter cups.
He delayed drinking it while spending time with his children, explaining why family came first.
“We still have pasta from Olive Garden. That was partially because I didn’t want to eat it and partially because we were at the end of an enjoyable time with the children,” he said.
“As you all know who have kids, there’s a fixed amount of time that you can have a nice time, and it does not come back around.”
The final push involved even more movement, including swimming, walking and treading water, before Hooper tallied everything up.
By the end of the challenge, he had accumulated 24,697 steps, completed 90 minutes of resistance training and spent time playing basketball.
Although he had originally set out to both eat and burn 10,000 calories, his final calculations suggested he fell slightly short.
“I have this ice cream to finish off my calories for the day,” he said. “It’s going to have me around 9,200. So I’m going to guess my calories burned were around 8,700. And that includes my resting metabolic rate, my general daily movements, my efforts to stay alive, my exercise, my everything.”
“That’s a surplus of 500 calories.”
Even after consuming well over 9,000 calories, the result wasn’t nearly as dramatic as many might expect.
“If I chose to live this way every single day, I would be on pace to gain approximately 1 lb per week. Not too bad for eating over 9,000 calories.”
Reflecting on the challenge after finishing the final milkshake, Hooper admitted the experience was surprisingly manageable.
“Done and dusted. That actually was concerningly not that hard. That is a lot of food and a lot of burnt calories.”
Still, he had no intention of repeating the experiment any time soon.
“That was not very fun,” he concluded. “And I’m going to be extremely sore for the next couple of days.”
Featured image credit: Mitchell Hooper / YouTube
