Evolutionary Explanations of Food Preference - Revision/Essay

Discuss 2 or more evolutionary explanations of food preference (8+16marks)

Psychologists have carried out much research into the origins of modern day food preferences. The evolutionary explanation of food preferences argues that our likes and dislikes for particular foods have their origins in the way we have evolved. In order to study this, we have to understand the Environment of Evolutionary Adaptation (EEA).

The EEA is the environment in which a species first evolved. For humans, it is thought to be in the African savannah 2 million years ago. Early diets would have consisted of foods high in fats and calories as they provided the most energy for humans to survive and find food for their next meal. Calories were not plentiful in the EEA and therefore were in high demand. This explains why even today, we have preference for fatty and calorific foods despite not needing the same amount of energy as we are no longer required to hunt for our food or burn as many calories.

Evolution can also explain our preference for meat. In the EEA, receding forests caused plant quality to decline, and humans turned to meat for an alternative. Milton 2008 suggests that without meat, we would not have evolved to be such intelligent or active beings as the amino acids, nutrients and minerals contained in meat were extremely beneficial. Fossils have shown that humans tended to eat the fatty organs of animals that they found, as they contained the most energy.

The Evolutionary Explanation can also explain our food dislikes through the Taste Aversion Theory. Garcia et al 1955 gave rats Saccharin, then immediately after made them ill from radiation. The rats developed a taste aversion to Saccharin because they associated it with becoming ill. This mechanism would have been advantageous in the EEA if we ate something poisonous and survived, as it would enhance our survival if we learnt to avoid it in the future.

Similarly, Garcia et al 1955 demonstrated a mechanism called the mecicine effect in which we develop preference for foods that enhance our health. Garcia gave Thiamine deficient rats a novelty food, then injected them with Thiamine. The rats developed a preference for the novelty food because they associated it with the positive feeling that Thiamine caused. This would have been advantageous for our ancestors in eating foods that were beneficial to their health.


There is support for the importance of calories in food preference. Gibson and Wardle 2001 found that when 4-5 year olds were presented with a selection of fruit and vegetables, the deciding factor in which one they chose was not smell, appearance, taste or familiarity, but was the density of calories that it contained (banana and potato). This clearly indicates that calorie content is a key preference in food choice and the fact that it was exhibited in young children suggests that it is indeed an evolved preference. Therefore food preference can be explained by evolution.

However, there is an issue with the theory behind our preference for meat. Abrams 1987 suggests that preference for meat has been found in all societies, and therefore indicates that the transfer from plants to meat was inevitable and not caused by the change in environment. Therefore this suggests that our preference for meat is not an evolved adaptation but an inevitable development in the evolution of our species, therefore evolution alone cannot really explain our meat preference.

Further criticisms of the evolutionary explanation of food preference argue that not all modern day preferences can be traced back to the EEA. Foods that are beneficial now: low calorie and low cholesterol would not have been advantageous in survival in the EEA. Moreover, high calorie foods and fatty foods are more maladaptive to health now than they are adaptive. This strongly implies that food preference is not determined by evolution as food preferences now would not have enhanced survival in the EEA.

However this can be explained by the development of society. We are no longer required to hunt or forage for our food and therefore require less energy and calories because we are less active. This explains why low calorie foods are more beneficial now and also gives an explanation as to why calorie rich foods are considered so unhealthy now and are often the cause of obesity - an increasing pandemic in the UK. Therefore whilst evolution can explain the food preferences of the time, other factors then shape our food preferences as we evolved, such as the development of society.

Despite this, there is research support for taste aversion from Sandell + Breslin 2006. They screen 35 adults for a bitter taste receptor gene that detects the presence of glucosinolates in food. In high concentrations, glucosinolates can be highly toxic and cause severe illness or death. Those with the most sensitive form of the gene rated bitter foods as 60% more bitter than those with the ordinary variant of the gene. The sensitive gene was also the most common form of the gene found. This suggests that our genes - determined by evolution - play a role in taste aversion and therefore enhance our survival. The fact that the gene was so widespread suggests that it meant those individuals posessed a selective advantage over their peers. Therefore this suggests evolution does shape our food preferences as well as our dislikes.

However, the evolutionary explanation is deterministic because it ignores the fact that individuals have particular food preferences that are determined by our own free will. For example, vegetarians choose not to eat meat on moral grounds, whereas the evolutionary explanation doesn't consider ethical objections to certain food preferences; it suggests that everyone eats meat because that is how we have evolved. Therefore the evolutionary explanation of food preference is limited.

Despite this, there is support from primates in how our ancestors would have eaten the fattiest part of an animal. Chimpanzees that were on the verge of starvation, when presented with a dead animal to feed on, chose to eat the fatty brain first over the nutritious flesh. This shows that there is preference for fat over nutrition which supports the evolutionary explanation of food preference.