The five food groups containing the most lectins are: 1  Grains: Especially those containing gluten, such as wheat. 2  Legumes: Beans, including soy and peanuts. 3  Dairy: If a dairy animal is fed grain rather than grass fed. 4  Nightshades: Common ones are tomato, potato, eggplant, and pepper. 5  GMO foods: Lectins are durable and toxic. Remove all five high-lectin food groups for a minimum of 2 weeks, ideally for at least 3 weeks. 2  After 3 weeks, introduce one food at a time from one food group. 3  Wait 72 hours before adding another food. 4  During the 72-hour waiting period, document any changes in mind, body, or spirit.