Serena Williams sports a super hero six-pack.

The world No. 1 dished on the diet and nutrition discipline that helps her sustain that powerful shape: Tacos.

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Actually, an aversion to red meat, a preference for fish and her commitment to eating clean are all components of the 21-time Grand Slam champion's dietary game plan.

Serena said she has not followed older sister Venus' lead in trying to adopt a vegan lifestyle.

"I've been eating tacos every night, so no chance (of going vegan)," Williams told the media in Indian Wells. "I don't eat red meat... I have not eaten red meat in a very, very, very long time."

During tournaments, Williams is more disciplined about her diet.

"I think generally during a tournament I eat a lot cleaner," the top seed said. "I don't really eat tons of meats or you know, usually stick to more fish."

Serena, who once shared Thanksgiving with director Spike Lee and his family in Florida, said she's discussed going vegan with her sister and friends, but has no plans to do it. Serena said she does an annual herbal cleanse, eating primarily raw vegetables to clean out her system.

"I talked to Venus about it and I know a few actors that have (gone vegan)," Williams said. "You know, I think it's just really good to clean out your system sometimes just to get rid of all the waste and things like that that are just in your system and let the earth from the plants really clean you out. So I'm a big believer in that.

"Every year I always do an herbal cleanse and really eat healthy for a couple weeks and really eat lots of raw greens and veggies. From a health standpoint, I just want to be as healthy as I can be, not only for sure tennis, but for my life in general."

Photo credit: Matt Hazlett/BNP Paribas Open