This is part of our Road Trip 2018 summer series "Taking It to Extremes," which looks at what happens when people mix everyday tech with insane situations.

This weekend all eyes are on the UFC.

On Saturday night, in the main event of UFC 234 in Melbourne, Robert Whittaker defends his middleweight title against rising star Kelvin Gastelum, a heavy handed striker with the potential to knock his opponent out at a second's notice.

It's nothing Whittaker hasn't dealt with before.

On June 9, 2018, Whittaker found himself in a similar fight, with similar stakes, in the Ultimate Fighting Championship's caged octagon, where for 23 years combatants have fought by mixing techniques from jiujitsu, kickboxing, wrestling and any other martial art that actually works.

Whittaker, the UFC's 28-year-old middleweight champion, is at the sharpest edge of arguably the world's most extreme sport. On that night in Chicago at UFC 225, a show that raked in a live gate of $2.5 million and had 250,000 others paying around $60 apiece to watch on pay-per-view, the Australian fought mixed martial arts legend Yoel Romero, of Cuba, in the prestigious main event.

Romero, a former Olympic wrestler, is a freak athlete. He's 41 but looks 21. He's stronger than Whittaker and moves more explosively too. Built like a granite sculpture, Romero has muscles so hard that Whittaker broke his hand punching him in the first round. For the remaining 20 minutes of the 25-minute fight, Whittaker had only one useful fist.

Yet Whittaker combined an iron defense, timing and precision to win by a narrow split decision.

Astonishingly, fighting in the octagon is the easy part of Whittaker's job.

Dylan Buell/Getty Images

The hard part, Whittaker has said, is getting to the fight. Grueling training and conditioning. Constant monitoring of nutrition and rest. And the weight cut: a dangerous process all UFC fighters go through that has them lose up to 20 pounds in water over five days so they can meet the strict weight limits in each fighter class.

The technology employed by Whittaker, an elite fighter in the UFC arena, is beguilingly simple. The lifelong gamer finds stress relief in the sprawling digital worlds of his favorite video games, and stockpiles data about his training and conditioning in Excel.

Yes, Microsoft Excel.

A team of five coaches rely on the same program used by number crunchers everywhere to hoard information on Whittaker, which they then use to fine-tune his body into the perfect fighting machine.

"The only predictor of future behavior is past behavior," says Fabricio Itte, one of Whittaker's coaches.

For the past five years, Itte has collected mountains of data about the fighter: weight, calorie intake, macronutrient split (finding the right balance of protein, carbohydrates and fat), resting heart rate, rate of perceived exhaustion, training volume. Whittaker can't take a step without it being recorded.

Nearly his entire training regimen revolves around collecting and analyzing the numbers.

Extreme Excel

UFC is a huge business. In 2016 -- 20 years after Sen. John McCain dismissed it as "human cockfighting" -- a consortium led by the William Morris Endeavor talent agency acquired the UFC for $4.2 billion. The previous owners, Frank and Lorenzo Fertitta, had bought the UFC in 2001 for $2 million, transforming the fight entertainment from a renegade mixed martial arts promotion to an international blockbuster.

Some fighters have criticized the company for underpaying its athletes, but there's serious money to be made at the highest levels. Those at the top of a pay-per-view card, an exclusive club that now includes Whittaker, can earn around $500,000 per fight. Become a big name star like Conor McGregor, known for his Muhammed Ali-esque ability to boost mainstream interest in a bout, and your annual earnings can soar into the $20 million range.

Yet with so much money at stake, Whittaker's team relies on filling out spreadsheets -- every day, all the time -- to get their man into fighting shape.

Itte tells me a carefully curated and monitored set of spreadsheets has created a real-life algorithm: The team has enough data to predict how Whittaker will react to almost any combination of training, food intake and rest. They use this to program him. If he needs to weigh a certain amount in four months, or feel a certain way in six months, they know precisely how to achieve that goal.

The key, says Itte, is creating a program built on an athlete's specific data. "A lot of the time [people] go, 'You're going to do these workouts and this is the diet you should follow," Itte says, explaining where trainers can go wrong.

"We've got the data and say, 'When you eat these foods, you're able to still work out. When you eat that and you drink like that, you're fine.' It doesn't sound like a big difference, but it is."

Dylan Buell/Getty Images

I asked Itte how often the strategy needs to be recalibrated. Is training on a given day based on how Whittaker feels? The answer: No calibration needed. The team already knows how Whittaker feels before he even arrives at the gym.

The equation could go something like this: Calorie intake and workload have stayed steady at X; resting heart rate (measured on the same Fitbit every morning on waking) rose to Y -- telling us that today Whittaker will feel Z.

The spreadsheets provide that window into Whittaker's fitness.

"It allows us to have written evidence on how we've been in previous [fight] camps, how I've felt with previous training," Whittaker says. "It allows us to take a scientific approach to workloads and exertion levels and whatnot."

That "whatnot" includes Whittaker's condition on fight day after the weight cut. It's a battle unto itself.

The fight before the fight

Whittaker weighs around 200 pounds, but he fights in the 185-pound middleweight class. That means he needs to lose at least 15 pounds the day prior to his fight. The weight-cutting process involves some dieting to shed fat, but it mostly uses extreme dehydration to drop weight in the week before the bout.

If you're overweight on weigh-in day, even by a fraction of a pound, you're either kicked off the card or stripped of a significant portion of the purse.

Whittaker was a beneficiary of this at UFC 225. Romero came in at 185.2 pounds. That meant Whittaker's middleweight championship belt was no longer at stake and 30 percent of Romero's payout, which was $350,000 for their last fight, went to Whittaker.

It's all about gaining a competitive advantage. A fighter who doesn't have to cut weight will be smaller and weaker than a 200-pound fighter who nips down to 185 for weigh-ins. But that bigger athlete will only be 185 pounds for around an hour.

Here's how the process works: Fighters diet in the weeks before fight week. Then, around five days before weighing in, they start reducing water intake. In the last 24 hours before weigh-ins, they usually drink no water at all. After a successful weigh-in, they have around a day and a half to refuel on food and water.

Christian Petersen/Getty Images

Kids, don't try this at home.

While a successful weight cut gives a competitive advantage, a poorly planned weight cut can be ruinous.

"When your body is that dehydrated, the kidneys are no longer operating at full capacity, so the organs can start to fail" explains Dominique Condo, a lecturer of sports nutrition at Australia's Deakin University.

Athletes can additionally ramp up dehydration by taking diuretics and spending lots of time in a sauna. That makes it even riskier to their health, Condo says. "When you're doing some of these things, it can make the heart work harder, so there's the risk of heart failure as well."

This is especially troubling at the amateur level, where less-experienced athletes and coaches may try to make up for poor planning with a last-minute dehydration dash. In December, amateur Muay Thai fighter Jessica Lindsay, 18, died following a mismanaged weight cut. Three years ago, 21-year-old Yang Jian Bing died after his weight cut led to cardiopulmonary failure.

Weight cutting is safe as long as it's planned far enough in advance by people who understand their athlete, says Condo. "This is an area where there isn't a blanket method or blanket rule," she says. Everyone is going to be so different.

"The more data you get on [the athlete] after they've been through periods of cutting and regaining, and what you did to get them there, the safer it will be."

Achilles' heel

It's tiring being an ultimate fighting machine.

Training for UFC competition is a constant mental and physical grind, says Whittaker. It's training multiple times a day, sometimes up to seven days a week, to improve your technique and conditioning. His program includes high-level Brazilian jiujitsu, boxing, wrestling and Muay Thai kickboxing, plus strength and endurance training.

"You know those hard days you go home where you've been worked to the bone and you just want to do nothing?" he asks. "In fight prep, every day is that day." That's where video gaming comes in.

Whittaker is an avid gamer, and online multiplayer games are his go-to -- he once joked about spending 60 percent of his UFC earnings on League of Legends items.

"It's definitely a reason I game so much: to forget about the pressures of fighting and the hardships of training and everything," he says.

Hey guys I’ll be streaming tonight playing Elder Scrolls online 7pmAEST on twitch hit me up at robwhittakermma👊🏽 @bethesda pic.twitter.com/EHjtt6d9Ov — Robert Whittaker (@robwhittakermma) June 22, 2018

Most athletes have a ritual on fight day to help them cope with anxiety and stress. Hours before his battle with Romero, Whittaker played The Elder Scrolls Online from his Alienware gaming laptop.

Now, with another win under his belt, Whittaker gets ready for his next fight, against a worthy contender. Kelvin Gastelum: a young, hungry contender with bricks for hands. It's an interesting stylistic match-up. Whittaker's last three match-ups have been against wrestlers and Jiu-Jitsu specialists: in short, people who have wanted to take him to the ground.

Getty Images

This fight will almost certainly be different. It presents a different set of risks. Whittaker's strengths are speed, unorthodox striking on the feet and incredible cardiovascular fitness. All of which will be tested come fight night.

But Whittaker confided to me one of his weaknesses. It's not something Gastelum can take advantage of when they finally meet.

"Microtransactions," he says guiltily, referring to the online stores where gamers buy in-game currency or items. "I have a bad habit of blowing my money on those things."

"Skins get wins!"

First published Aug. 20, 2018 5:30 a.m. PT

Update, Feb. 5 at 2:54 p.m.: Recasts with information on Whittaker's upcoming title match against Kelvin Gastelum.

The Smartest Stuff: A look at the people working to make you — and the world around you — smarter.

Life Disrupted: Reporters' dispatches from the field on tech's role in the global refugee crisis.