My children are 36, 30, 28 and 26 with 11 grandchildren. I have heard it all and tried a lot. I have also had a day care and am now working as a nanny. I am also in the health care field as a natural health healer. A baby's digestive system takes awhile to mature. Giving them solids before this time invites allergies and other problems. Waiting until 6 months or beyond is really best for baby. Brown rice cereal is much higher in nutrition than white. Avocado, mashed and thinned with water or milk, is another good first food. Cooked sweet potato, mashed and thinned, also, is another, if baby is about 6 months. Other cereals can be made by grinding the whole grain in a blender for 2 minutes, then added slowly to boiling water, stirring often, cooking for 10 min. Thin with water or milk to feed baby. Millet (a perfect first food), buckwheat, and quinoa are excellent choices, too. Your son has a hearty appetite, but 36 oz a day is not unusual. Starting him on foods his digestive system is not ready for has the potential for other problems later. Size is not a determination for starting a young baby on food. My youngest weighed over 10 lbs at birth and didnt start eating solids until almoet a year old, being fully breastfed. She is my healthiest child, even today. Ruth Yaron's Super Baby Food book covers all the info anyone needs about feeding baby, when, what, how. (I very much disagree with her advice to microwave the food to heat it, but otherwise, it is a super book)