When moms say their toddler is not eating "the way she should" or talk about "rules of eating" and their toddler's eating habits, you know, eating one day and refusing to even look at food the next, that sort of "abnormal" behaviour, there are two things to remember. One, there is no rule that says a toddler has to eat a certain way because there is no normal way for toddlers or children of any age to eat. There is no normal in eating. One of the exciting things about being a doctor is that one is constantly reviewing one's idea of what is "normal" because one sees so many different aspects of "normal" life or illness or reaction to life or to illness.
In fact there is no normal. Ask your friendly cocktail party psychiatrist or schoolteacher pretending to be a psychologist if you don't believe me.
Normal carries the meaning: conforming to a standard; usual, typical, or expected. It is a theoretical term that has no basis in human life. Few healthy people conform and even then, not all of the time. That is normal. It is normal for humans to be abnormal ie not conforming or not doing the usual or typical thing or the expected. The only people who believe in normal are mathematicians, religious fanatics, obsessive-compulsive depressives and makers of infant formula, who started the nonsense that babies need to eat every four hours and have three bowel movement's a day or they are not "normal." Or that toddlers need to sit down at a table with two ounces of potato, one ounce of boiled fish and three ounces of apple juice and eat everything and then go to sleep, the little angels. That does only happen in Hollywood. You see how complicated this "normal" thing gets? What some people think is normal is really abnormal, but since they talk loud or have lots of money, gullible island people believe them.
Two is that if they leave the child alone, unless the child has been spoiled, the child will eat everything it needs to grow and develop into a healthy adult. Spoiling refers to those "helicopter" or "hummingbird" moms who hover constantly over their child, demanding this, expecting that, nagging, worrying, going by the book, "you must eat green peas by five and three quarter months" or something dreadful will happen. Or those who have taught their child to overeat by encouraging them to drink more and more formula in the first few months of life.
Breastfed babies do not have this problem since breastfed babies control the amount of milk they ingest. This is a classical example of the wisdom of the body. Breastfed babies know exactly how much breastmilk to drink and not a drop more. Amazingly their mother's breast also knows exactly how much milk and what kind of milk to produce for her baby. We haven't worked out exactly how that supply and demand system works but it certainly involves signals, visual or auditory or tactile or olfactory or hormonal or some or all working together, sent to the breast from the baby and back again. There is this constant back and forth communication, a dance if you will, between the baby and the mother and her breasts, which one does not notice unless one studies the phenomenon and that has only been done in the last ten years or so because remember, up to the late seventies, such was the effect of formula company brainwashing, we all thought that formula was just as good as breastmilk.
Like blood, breastmilk is a complex, living substance, constantly changing according to the needs of the baby. No two breasts are the same, even in the same woman, but all breasts regardless of size or shape, can produce milk. The production of baby-specific breastmilk is one of the untold mysteries of nature. How many know that breastmilk from the two breasts, same woman, is different at different times of the breastmilk production cycle? (That may explain why some babies occasionally prefer one side to another). How many know that the breast milk of diabetic mothers has a slightly different composition from that of non-diabetic mothers but is still unique to her child's needs? Still good milk but it means certain maternal conditions are factors in the composition of human milk.
Most people know that, like finger prints, the breastmilk of one mother is quite different from the breastmilk of another but how many know that breastmilk from the same mother differs from month to month, week to week, hour to hour and even during a feed. Take fat. Fat is not a constant in breastmilk. The concentration of fat in a breast varies with the specific fat needs of that baby drinking that milk from that breast. So the breastmilk fat content of a three-day-old child's mother is quite different from that same mother's breastmilk at three weeks or three months or three years. It varies from day to day, during the day and during the feed. So some babies breastfeed every hour, some every two, some all the time. And it changes, depending on the nutritional needs of the baby.
There is no rule. There is no normal.
Apply this to the thousands of known ingredients of breastmilk (Google 'How many substances are there in human milk?'), all constantly changing and mixing and interacting among themselves with the baby's needs and demands. What do you do? How do you decide when to feed and how long to feed? You cannot. All you have to do is trust your body and your baby and everything will work out. Breastfeeding babies is one of the marvels of life. It was needed for life to exist and that is how we have survived and evolved.