Are we wired to eat healthy? Surprising study finds humans possess intuitive ‘nutritional wisdom’

Are humans wired with the ability to intuitively choose nutrient-dense foods in ever-changing varieties that match the body’s needs of the moment? If our body cries “Pizza, NOW!” are we compelled to respond to the call? It is estimated, however, that by the year 2030, half of the adults in the United States will be considered obese. What happened to our so-called intuitive food choices? 

Research, led by scientists at the University of Bristol in England, sheds new light on what drives food preferences, indicating our choices may be smarter than previously thought. Those choices are  influenced by the specific nutrients needed, as opposed to just calories.

The study aimed to test the widely held view that humans have evolved to favor energy-dense foods, balanced by eating a variety of foods. Scientists report that their findings indicate “nutritional wisdom,” that is, foods were selected to meet the need for vitamins and minerals, and to avoid nutritional deficiencies.  

“The results of our studies are hugely significant and rather surprising,” admits co-author Jeff Brunstrom, a professor of experimental psychology at Bristol, in a statement. For the first time in almost a century, we’ve shown humans appear to select foods based on specific micronutrients, rather than simply eating everything, and getting what they need by default.”

The new study supports research from the 1930s. Dr. Clara Davis, an American pediatrician, put 15 babies on a diet in which they ate whatever they wanted from 33 different food items. It was reported that hey all achieved and maintained good health, attributed to this so-called “nutritional wisdom.”

Its findings were suspect, but replicating Davis’ research was not possible because it was considered unethical.

Brunstrom’s team designed a study which measured preferences by showing people images of different fruit and vegetable pairings. Their choices could be analyzed without putting their health or wellbeing at risk.

A total of 128 adults participated in two experiments. The first showed that people prefer certain food combinations more than others. For example, a pairing of apples with bananas was chosen more often than a pairing of apples with blackberries. Preferences appeared to be a function of the amounts of micronutrients in a pair and whether their combination provided a balance of different micronutrients. 

The second experiment studied meal combinations as reported in the UK’s National Diet and Nutrition Survey. These data demonstrated that people combine foods that increased exposure to micronutrients. Specifically, components of popular UK meals, for example “fish and chips” or “curry and rice,” seem to offer a wider range of micronutrients than meal combinations generated randomly, such as chips and curry. 

The study featured an unusual collaboration. Professor Brunstrom’s co-author is Mark Schatzker, the writer-in-residence at Yale University’s Modern Diet and Physiology Research Center. They met in Florida at the annual meeting of the Society for the Study of Ingestive Behavior, where Schatzker delivered a talk about his book, The Dorito Effect, which examines flavor and the implications for health and wellness. 

“This was all very intriguing, so I went to see him at the end and basically said: ‘Great talk, but I think you’re probably wrong. Do you want to test it?’ That marked the start of this wonderful journey, which ultimately suggests I was wrong,” explains Brunstrom. “Far from being a somewhat simple-minded generalist, as previously believed, humans seem to possess a discerning intelligence when it comes to selecting a nutritious diet.”

Adds Schatzker: “The research throws up important questions, especially in the modern food environment. For example, does our cultural fixation with fad diets, which limit or forbid consumption of certain types of foods, disrupt or disturb this dietary ‘intelligence’ in ways we do not understand?

“Studies have shown animals use flavor as a guide to the vitamins and minerals they require. If flavor serves a similar role for humans, then we may be imbuing junk foods with a false ‘sheen’ of nutrition by adding flavorings to them. In other words, the food industry may be turning our nutritional wisdom against us, making us eat food we would normally avoid and thus contributing to the obesity epidemic.” 

Brunstrom’s paper is published in the journal Appetite.

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