Move over spinach.

Broccoli and mustard greens could also build up Popeye's muscles, according to research conducted by North Carolina State University, Kannapolis.

The members of the Brassica family contain brassinosteroids, which trigger a physiological response in rats similar to anabolic steroids, according to a news release.

Researchers studied how rat skeletal muscle cells responded to the plant steroid homobrassinolide.

They then measured how the cells responded to brassinosteroids.

What they found was the brassica-based steroid increased protein synthesis and decreased protein degradation in cell culture.

When rats were fed homobrassinolide for 24 days, they gained lean body mass compared to those not fed the substance.