In an article from Livestrong.com

Barbara outlines the basic's of the Kosher diet. The essential sticking points being that it is healthy clean eating. 

The kosher diet is based on a body of Jewish law called the Kashrut. It specifies foods that can and cannot be included in the diet. It also includes the different requirements for preparing and serving kosher food. Rabbis examine the food to be certain that its handling and processing meets the requirements.

All fruits and vegetables are considered kosher. But the insects that may be found on them must be removed. All produce must be inspected prior to use. Some specific fruits and vegetables have a higher likelihood of harboring insects and receive special attention. According to Star-K, the kosher certification organization, artichoke leaves can not be included in the kosher diet because they cannot be adequately examined. However, the artichoke bottom can be eaten after is has been washed and cooked.