Madonna's Daughter Lourdes Looking Hot AND Hungry On the Beach

Madonna's daughter, Lourdes Leon, gave new meaning to the phrase ... suns out, buns out when she hit South Beach ... with her appetite.

Madge's 20-year-old not-so-baby girl slipped into a bikini -- showing off what her mama gave her -- and also made sure to take a food break.

Lourdes absolutely inhaled a sandwich out on the beach. See, don't worry Mom ... she's eating.

And looking very healthy.