Want to maintain your happiness, sex life and spirit? It may seem obvious, but ‘don’t gain weight’ says Chris Pratt.

In an interview with Men’s Health UK, the Hollywood star revealed he was impotent and depressed when he weighed 300 pounds (136kg).

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Pratt with his wife, Anna Faris. Photo: Getty

“I was impotent, fatigued, emotionally depressed,” the 35-year-old said.

“I had real health issues that were affecting me in a major way. It’s bad for your heart, your skin, your system, your spirit.”

The actor also revealed the exact moment he decided to get fit and stay fit.

“I’d gone back and forth, lost weight for Moneyball, got fat again, then trimmed down for Zero Dark Thirty, then gained it all back again for Andy [his Parks and Recreation character],” Pratt said.

“That’s when I saw Zero Dark Thirty and right after walking out I was like: ‘I’m going to get in shape and I’m never going to be fat again.”

Pratt, who stars in this year’s Jurassic Park remake, partly blamed his weight loss on his marriage to wife of six years, Anna Faris.

“We were drinking a lot of wine and having fun. I was her little Hansel out in the woods and she was fattening me up to put me in the fire,” he said of Faris, who is also an actor.

“It was like Momma Bear and Papa Bear. She would eat a little bit, I would eat all of mine and the rest of hers.”

Pratt lost nearly 30 kilograms of fat for last year’s Guardians of the Galaxy and has maintained his physique ever since.