I just read this in my psychology book, which I think some people will find obvious, but also interesting.
"There is some evidence that humans, given the opportunity, can also learn which foods promote their health. In the 1920's a pediatrician named clara davis performed a bold experiment on food selection with human infants... The infants... lived in the pediatrics ward of a hospital for 6 months or longer... At each meal, a tray with about a dozen different foods was placed before each infant and the infants were allowed to choose their own foods and feed themselves. The choices were all natural foods- including cereals, fruits, ground meats, fish, eggs, and vegetables- but no single food contained all the required nutrients. The result was that the infants showed strong preferences for particular foods for periods up to a week, but then changed their preferences such that ,over time, they ate a balanced diet. At the beginning of the experiment one of the babies had rickets, a disease caused by lack of vitamin D. He self-selected cod-liver oil, which is rich in vitamin D, until his rickets was cured, and then he stopped selecting it. ...
We must be cautious in interpreting it. Perhaps it was just coincidence that the infant with rickets chose to eat cod-liver oil, perhaps the infants changed food preference simply because.. they became bored... maybe their choices had nothing to do with nutritional need... Should this experiment tempt you to assume that your own appetite system will choose a healthy diet in all conditions, please keep in mind that all of the choices in Davis's experiment were natural and unsweetened. Even rats lose much of their ability to learn which food is good for them if one or more of the deficient foods is laced with sugar. From an evolutionary perspective, that is not surprising. The food-learning system in rats and humans evolved long before refined sugars were invented."- Peter Gray
"There is some evidence that humans, given the opportunity, can also learn which foods promote their health. In the 1920's a pediatrician named clara davis performed a bold experiment on food selection with human infants... The infants... lived in the pediatrics ward of a hospital for 6 months or longer... At each meal, a tray with about a dozen different foods was placed before each infant and the infants were allowed to choose their own foods and feed themselves. The choices were all natural foods- including cereals, fruits, ground meats, fish, eggs, and vegetables- but no single food contained all the required nutrients. The result was that the infants showed strong preferences for particular foods for periods up to a week, but then changed their preferences such that ,over time, they ate a balanced diet. At the beginning of the experiment one of the babies had rickets, a disease caused by lack of vitamin D. He self-selected cod-liver oil, which is rich in vitamin D, until his rickets was cured, and then he stopped selecting it. ...
We must be cautious in interpreting it. Perhaps it was just coincidence that the infant with rickets chose to eat cod-liver oil, perhaps the infants changed food preference simply because.. they became bored... maybe their choices had nothing to do with nutritional need... Should this experiment tempt you to assume that your own appetite system will choose a healthy diet in all conditions, please keep in mind that all of the choices in Davis's experiment were natural and unsweetened. Even rats lose much of their ability to learn which food is good for them if one or more of the deficient foods is laced with sugar. From an evolutionary perspective, that is not surprising. The food-learning system in rats and humans evolved long before refined sugars were invented."- Peter Gray
