The third group to introduce is vegetables. The fourth food group to try is meats. Lamb and beef are less allergenic and may be started first. Also at this time egg yolks may be started. The egg whites tend to cause allergies and should be avoided early on.
Egg yolks are a good source of iron.
The cholesterol contained in the yolks is needed by the baby, though it may be harmful to hearts of adults. Babies may take as many yolks as they like, but adults should not take more than 4 yolks per week. The amount of food babies eat varies, depending on their size, rate of growth and metabolism. For the first 20 pounds, infants use about 50 calories per pound. Generally, people do better with a variety of foods at each meal, rather than a large quantity of only one food at each meal.