Carnitine is an amino acid that most of us are able to get plenty of in in our diets from foods that contain protein. Animail proteins such as beef, pork, chicken, and dairy products contain carnitine; avocados are the highest-containing plant food. Carnitine is necessary to carry fatty acids that come from fat in our diets into our cells. Although our body is able to reuse carnitine, it is believed that more may be necessary on the ketogenic diet. A carnitine blood level is helpful in determining this.