Nutritional intelligence: do we have an inbuilt capacity to recognize differences in food composition?

By Bhavana KunkalikarReviewed by Danielle Ellis, B.Sc.Feb 14 2023

In a recent study published in Physiology & Behavior, researchers explored food sensitivities found in daily dietary decisions based on food composition.

Background

Our complex relationship with food is influenced by the social as well as cultural importance of food, which permeates every facet of our eating behavior. To find order among this diversity, scientists frequently search for dietary "universals," - which include phenomena or fundamental rules that govern human food selection and portion size regardless of circumstance.

One such theory is that flavor traits serve as an indicator of food make up. Others have proposed that behavior is influenced by learning and depends on the associations formed between the flavor of a dish and its post-ingestive impacts. Despite a considerable body of study, the data supporting both processes is inconclusive, leading some researchers to believe that people are generally indifferent to food composition.

Nutritional intelligence drawn from basic tastes

Several researchers opine that taste is crucial in determining human nutrition. Basic tastes are frequently referred to as having a "nutrient-signaling function" either since taste-nutrient correlations are learned or since taste offers a simple hard-wired feedback on food composition. Some studies claim that sweetness can help determine the carbohydrate composition of a particular food item, whereas bitterness may indicate the presence of a harmful substance.

If we rely exclusively on taste-nutrient connections, then the magnitude to which changes in flavor attributes may predict food composition will determine the limitations of human nutritional intelligence. If taste-nutrient correlations are poor, there will be fewer opportunities to choose nutritious foods.

This has led to varying taste-nutrient connections. However, after comparing data across studies, the team estimated that differences in the intensity of umami and sweetness likely account for approximately 20% of the variation in macronutrients. This implied that if humans depended entirely on these signals, we would be unable to make optimal food choices.

The characteristics of these flavor-nutrient correlations also require thorough research. Some researchers argue that taste functions as an unlearned and unconditioned stimulus, whilst others consider these relationships to be learned, with the intensity of the association between flavor traits and their corresponding nutrients modifiable over time. The latter is specifically pertinent to the assumption that modern food processing technologies and ingredients degrade the human capacity to depend on taste as an indicator of nutrient content.

Nutritional intelligence in common foods

Studies focusing on short-term controls of meal size typically utilize "amount consumed" as their dependent measure of interest. Since it is commonly believed that satiety develops while consuming a meal, it is hypothesized that meal size will be influenced by the magnitude to which food induces satiety as it is consumed. Humans plan the amount of food they will consume before eating, which is observed in the general tendency to either "plate clean" or not be surprised by the amount of food left after the meal has ended. The team also observed meal planning in a restaurant under normal conditions, and it is also visible in extensive qualitative analyses of interactions of consumers with food portions.

The researchers hypothesized that people discriminate between foods according to the level of satiety they anticipate to gain. This was tested by developing a 'method of constant stimuli', which led to two observations. When calorie-for-calorie comparisons were made across 18 common, everyday items, 'anticipated satiety' varied significantly.

In particular, meals such as potatoes were predicted to provide more than three times as much satiety as snacks like cashew nuts. Also, these distinctions were not random since several variables predicted them. Specifically, meal energy density served as an accurate predictor of anticipated satiety, while measures of anticipated satiety were powerful predictors of actual satiety.

The correlations between expected satiety, food preference, expected satiation, and dietary composition demonstrated by these data is evident and predictable. In other words, there appears to be considerable evidence that humans are nutritionally intelligent. Studies have suggested that humans tend to consume food based on volume. This indicates that food energy density significantly impacts the number of calories ingested during a meal and that this explains the human propensity for "passive over-consumption."

Conclusion

The study findings showed that common dietary preferences depend on cultural transmission as well as shared encounters with food, which may be a fundamental component of a long-term biological process, including taste-nutrient signaling and flavor-nutrient learning. This implied that biological and cultural factors of behavior could not be easily distinguished, and their intersection is crucial to understanding behavior. The researchers believe that the present study could facilitate the development of a scientific framework by initiating a broader dialogue across different areas of research.