The child, named Schizandra, then moved on to sardines, butter and ice pops made out of bone broth. She gnawed on leg of lamb.

"She would just teethe on that and soothe herself," said Quenneville, 31.

Schizandra is what her mom calls a "carnivore baby." Most of her diet is meat, along with other animal-sourced foods like eggs and butter. "She's an easy baby," said Quenneville of her daughter, now almost 2. "I believe that the food in the diet is a very, very big piece of that."

With the carnivore diet rising in popularity among adults, babies and toddlers are getting in on it, too. Moms swap tips—think directions for whipped bone marrow—on Facebook forums with names like Carnivore Motherhood.