Cooking is an important behavior that significantly impacted human evolution, evidenced by the brain expansion, reduction in masticatory anatomy, and gut reduction that resulted. Cooking may have influenced human evolution in ways other than biologically. One aspect of modern humans today that peaks interest is the existence of pair bonds in multifemale-multimale communities (Wrangham et al., 1999). This is unique because in most multifemale-multimale nonhuman primate communities, females and males do not establish stable pair bonds but rather have multiple mates (Dixson, 2012). There exists a hypothesis that cooking led to the rise of these pair bonds. Cooking food would have meant that feeding was postponed due to the time put into collecting the food that would be later cooked, and it would have had also meant that there was a large gathering of food that was vulnerable to theft (Wrangham et al., 1999). With situations like these, the thief is normally the dominant individual whereas the subordinates are normally the ones who do all of the grunt work (Wrangham et al., 1999). In the situation with hominins, the males would typically be the ones expected to steal from the females (Wrangham et al., 1999). This would have, therefore, led females to seek alliances with males who would be willing to defend them from these potential thieves in order to minimize resource loss (Wrangham et al., 1999). Males would have had desired to increase their number of matings while females would have had desired these matings to establish a relationship for food protection (Wrangham et al., 1999). There certainly would be female-female competition for the best-equipped males to guard the food, and this competition would have been indicated by an increase in female sexual receptivity (Wrangham et al., 1999). The existence of intense female-female competition would have meant that there was a decrease in sexual dimorphism, based on the knowledge that high sexual dimorphism exists in species with a lot of male-male competition (Dixson, 2012). This decrease in sexual dimorphism is seen in male body size drop in H. erectus, which is the first time a drop occurs in hominid evolution (Wrangham et al., 1999). This hypothesis concludes that cooking initiated the establishment of protective relationships between females and males within a multimale-multifemale society. It is important to note that this hypothesis does not explain the monogamous nature of our pair bonds today, but it does introduce a potential pathway by which pair bonds came to exist.
While cooking holds adaptive value and has greatly impacted the way modern humans evolved to be the way we are today, it has also been a reason for the existence of many metabolic diseases. When looking at many metabolic diseases through an evolutionary perspective, these diseases appear to be mismatch diseases. A mismatch disease is a disease that results from our current modern human bodies being poorly adapted for the environment that we are in right now (Lloyd et al., 2011). Cooking evolved in an environment where individuals experienced difficulties gathering the food energy that they needed. However, modern humans today live in an environment where we no longer have to spend time foraging or worry whether or not we are going to have access to food or not. We now live in an environment where food is readily available to us, especially cooked food. This is unusual to our Paleolithic evolved bodies.
Obesity is currently a global epidemic, and its incidence has risen significantly in the past century (Genné-Bacon, 2014). There appears to be both an environmental and genetic component to the development of obesity, and one prominent hypothesis called the Thrifty Gene Hypothesis seeks to explain our predisposition to obesity. This hypothesis proposes that the ability to become obese was a survival mechanism in the environments early Homo lived in where there were cycles of famine and food surplus (Genné-Bacon, 2014). With the ability to store extra energy as fat reserves, this would have been useful as a source of energy in periods of famine causing natural selection to select for genes that allowed for easier fat storage (Genné-Bacon, 2014). On the contrary, genes that readily store energy as fat reserves are maladaptive in our current environment, especially in an environment where we primarily leave sedentary lifestyles unlike early Homo who expended much energy foraging and travelling long distances. Cooking adds fuel to this fire by allowing greater energy extraction from food. With obesity comes a greater risk of developing other metabolic diseases such as Type II Diabetes. A common feature of obesity is an increase in abdominal fat, and abdominal fat seems to be linked to insulin resistance, a key characteristic of Type II Diabetes (Carey et al., 1996). Insulin resistance means that the body is not able to react to the normal levels of insulin that is produced by the body; therefore, the body does not effectively store glucose present in the blood (Shah & Vella, 2014). The body actually requires greater levels of insulin to respond, but the pancreas is later unable to produce these high levels of insulin (Shah & Vella, 2014). Later, blood glucose rises to high levels, which can damage nerves and blood vessels, and this subsequently leads to other health problems such as kidney disease, blindness, stroke, heart disease, and more (Shah & Vella, 2014). While cooking was an important adaptation in the early Homo environment, it has unfortunately paved the way for several metabolic diseases to come into existence in today’s modern society.