5 surprising facts about Arnold Schwarzenegger's diet and exercise routine from his new docuseries

• Iconic bodybuilder Arnold Schwarzenegger opened up about his fitness career in a new Netflix series.
• The seven-time Mr. Olympia shared the workouts he did as a teen, and his approach to dieting. 
• Schwarzenegger also revealed disappointing moments in his career and experimentation with steroids. 

A new Netflix docuseries on Arnold Schwarzenegger offers an inside look at the legendary bodybuilder's lifelong fitness career, from his teenage gym routine to dabbling in steroids as a pro athlete.

Along the way, the actor-turned-politician opened up about his workouts and eating habits, as well as some surprising setbacks he faced on the way to becoming the seven-time winner of the coveted Mr. Olympia title in "Arnold."

As a teen, Schwarzenegger spent three hours a day in the gym 

Schwarzenegger said his interest in bodybuilding began early in his life when he became fascinated by muscular icons like Reg Park.  As a young teen, he tagged along with a crowd of weightlifters and wrestlers who hung out at a local lake. 

Many of them trained at a weightlifting gym called Athletic Union in Graz, Austria, which Schwarzenegger joined so he could work out, too. 

"I could train, finally, with the big boys," he said. "This weightlifting club became, for me, the mecca. I became addicted to that, so I went every day."

Schwarzenegger said he would write on the wooden wall of the gym with a piece of chalk, marking down a line for each set he performed for each body part, such as biceps, triceps, chest, and back. 

The workout would be finished once he performed 20 sets of exercises for each, such as bicep curls and bench flies, to build a physique like those of his idols. 

"Now after three hours of training, this whole thing would be full of sets that I've done to get to that goal," he said. 

A mentor told Schwarzenegger his biceps were too big compared to his calves

All the training paid off, and Schwarzenegger began winning competitions and being noticed by big names in international bodybuilding. He was eventually invited to work out and compete in London, at which point his focus on building a massive upper body backfired. 

One of his early mentors, bodybuilding trainer Wag Bennett, complained that Schwarzenegger needed to work on a balanced physique by developing his legs more, since his calves were dwarfed by his biceps. 

"The calves are skinny, and the whole proportion is off," Schwarzenegger said. "If you want to win, you need to be fine-tuned, and you have to have everything at ten."

Schwarzenegger took Bennett's advice, and it paid off, earning him first place in the Mr. Universe contest in 1967. 

He lost the 1968 Mr. Universe competition in America because he had too much body fat 

Following his Mr. Universe win, Schwarzenegger attracted the attention of Joe Weider, the "godfather of bodybuilding" who had his own version of the competition in Miami. 

Confident he could win, Schwarzenegger said he was devastated and embarrassed when the judges called his name for second place. Instead, the top title went to American bodybuilder Frank Zane, who said in the docuseries that Schwarzenegger had plenty of mass, but wasn't lean enough to be a first-place winner. 

"He was acting so arrogant and cocky like he was the winner, but he wasn't in shape. It was all about being big and you know, size with him," Zane said in the docuseries. 

Schwarzenegger said he then traveled to Los Angeles to work with elite bodybuilders and trainers, who told him he had potential, but needed to get rid of a lot of body fat. 

Joe Gold, the owner of Gold's Gym, even called him "balloon belly," according to Schwarzenegger.  

Schwarzenegger said he's never been a 'fanatic' about his diet or counted calories

After being advised to slim down, Schwarzenegger changed his eating habits, but has previously said he never counted calories. 

"I was never a fanatic about diet," he said in the docuseries.

Instead, Schwarzenegger said he made sure to get plenty of protein and would start eating later in the day to lose weight.

He said his training partners, Franco Columbu and former rival Zane, also helped him get into supplements, including a regimen of vitamins and supplements.

He "experimented with" steroids but said it was only a small part of his overall fitness plan

But vitamins weren't the only thing giving Schwarzenegger a boost during his pro era — he said he also "experimented with" steroids. He said the cycles lasted for fours months a year with a doctor's supervision and strict rules. 

"Everybody in the bodybuilding field who is up there on the top is taking steroids," Schwarzenegger said in a clip of an earlier interview featured in the docuseries. "Maybe 5% of my progress is from the steroids."

Schwarzenegger has since been outspoken about the risks of substance use. He has said bodybuilding is one of "the most dangerous sports" in the world as competitors strive for more and more mass, often at the cost of their long-term health.