How the Western Diet Has Changed the Human Face

eating-ice-creamMost people know that children who grow up eating a processed, nutrient-poor diet are at increased risk of a wide range of medical problems, including obesity, type-2 diabetes, and hypertension. What is less known is that diet – particularly the diet you eat when you grow up – can have a major impact on the development of the bones, jaws, and face. There’s solid evidence to show that the “soft” modern diet, in conjunction with other factors associated with Western lifestyles, can promote abnormal development of the skull and face, and cause malocclusion, impacted wisdom teeth, and narrow dental arches.

The importance of chewing

In the ancestral health community, a lot of focus is placed on how the nutritional value of the human diet has changed since our days as hunter-gatherers, and how we can adjust our modern diet so it has a composition, macronutrient distribution, and micronutrient profile that more closely resemble that of ancestral human diets. Less attention is given to how the “hardness” of our diet has changed since the preagricultural era, and in which ways this might impact human health, growth, and development.

That’s not to say that nobody has been paying attention to this issue, as there has been some blog posts, presentations at conferences, and articles on this topic. However, in general, it’s safe to say that it’s definitely a subject that deserves more attention. Dr. Mike Mew, a London-based Orthodontist, estimates that modern humans use the masticatory system about 3-5% of what Paleolithic humans did, and that’s before you consider non-nutritional exercise of the jaws (i.e., using teeth as tools to make clothes and weapons) (1). 3-5%! That’s a big decline...

A common belief is that teeth alignment and development of the jaws are purely genetically determined. However, what we have to remember is that our genetic heritage isn’t the end all be all for how we are going to grow and develop. There’s a constant interaction between our genome and the environment, and the forces applied to structures during growth will affect how genes are expressed and the development of the size and shape of each structure.

In the same way that you won’t develop healthy and strong limbs if you’re not adequately stressing them through walking, running, and other physical activities during childhood, your jaws won’t grow correctly if you don’t stress them sufficiently from chewing. Chewing on hard, tough food is important because it activates bone cells in the tooth socket and promotes the growth of big and strong jaws in which there is adequate room for the third molars. There’s no doubt that our time spent running, walking, and otherwise moving our bodies has gone done dramatically since our days as hunter-gatherers. However, this reduction fades in comparison to the decline in masticatory effort and usage.

Soft diets cause dental arch abnormalities

Studies in many different animal species show that animals who are put on a diet of soft, processed food when they are young develop many of the same dental arch abnormalities as contemporary humans, such as malocclusion, narrowed dental arches, and crowded teeth (2, 3). One example is a study of hyraxes (relatives of elephants that chew like humans) fed nutritionally identical hard and soft diets. This study found that hyraxes raised on hard food developed jaws that were significantly longer, thicker, and wider than the ones who chewed softer food (4).

There is strong evidence to suggest that many of the same principles apply to our species as well. Studies – such as those carried out by researchers like Dr. Robert S. Corrucini, who campaigned the idea that malocclusion is a disease of civilization, and Dr. Weston A. Price, who documented the health condition of isolated, traditional populations before and after westernization – show that people who transition from a traditional lifestyle and nutrient-rich, whole foods diet to a western lifestyle and nutrient-poor, processed diet experience a rapid decline in health (5, 6). Moreover, there’s a high incidence of malocclusion, crowded teeth, and tooth decay among the children who are born and raised in the “westernized environment” (5, 6).

A study of younger Australian Aborigines whose families recently started eating processed, modern foods is one of the many examples of cases where these effects are seen. This study found that the younger family members had smaller jaws and serious tooth crowding problems compared to elder members of their families who grew up eating traditional food (5).

As for intervention trials, one small study that investigated the effect of masticatory muscle training on facial growth in long-face children found that children who chewed on hard resinous gum for two hours each day for one year grew larger jaws and developed straighter teeth (7).

Besides reduced use of the masticatory system, other factors, in particular pacifier sucking, bottle-feeding, incorrect oral posture, and poor maternal and childhood nutritional status may also be important contributors to the high prevalence of malocclusion, crowded teeth, and narrow dental arches in westernized societies.

Shrinking faces

Hunter-gatherers and traditional, isolated people generally have broad dental arches, well-aligned teeth, and ample room for third molars (2, 6, 8). Moreover, examinations of fossils indicate that prior to the Agricultural Revolution, malocclusion and impacted wisdom teeth were virtually unheard of (2, 5, 8). This is in stark contrast to modern societies, where these conditions are extremely common.

In industrialized countries such as the U.S., approximately 50% of all wisdom teeth are removed and about 95% has deviations in their dental alignment (1). Of these 95%, some 30% are recommended orthodontics treatment, a treatment that improves the symptoms present, but may actually worsen the underlying problem (1).

Modern faces are “melting down” in the sense that there has been a major change in the human skeleton since the Paleolithic era. Over the last few thousand years – a blink of an eye from an evolutionary perspective – human faces have become approximately 5 to 10 % smaller after correcting for body size (2).

Some would argue that beauty is in the eye of the beholder and/or that culture is the main factor involved in determining what we perceive as aesthetically pleasing. However, we also have to remember that we have evolved an attraction to certain features as a way to distinguish the healthy and virile from the weak.

Physical attractiveness can serve as a biological signal of good health, and we probably find people with well-developed faces, strong jaws, and broad dental arches attractive because these features are indicators of good genetic qualities and health.

Besides being aesthetically unappealing, the change to a longer, thinner craniofacial structure has had important implications for how we breathe, chew, and function.

Processing, cooking, and blending

The introduction of dairy products and cereal grains into the human diet with the Agricultural Revolution marks the beginning of a transition from a hard, tough, and fibrous low-calorie density human diet to a more soft and calorie-dense diet. This change has accelerated in pace and force over the last couple of centuries, as refined grains, vegetable oils, refined sugar, and processed junk food have entered into the human diet in large quantities. Add to that the fact that we now heat, ground, and soften up a lot of the food we eat, have access to blenders, grinders, and other food processing machines, and use knives and forks to cut our meals into nice, easy-to-eat pieces, and you can easily understand that the chewing effort needed to gain calories has declined dramatically since our days as hunter-gatherers.

Since most of the food available to our ancient ancestors in the wild had a relatively low calorie density compared to the food we find at our grocery store today, they had to eat a higher volume of food than we do today to get the same amount of energy. To get 1000 calories from wild meat and fibrous plant foods, you have some chewing to do, whereas to get an equivalent amount of calories from a soda, you barely have to stress your jaw musculature at all. For example, the Hadza spend a lot of time chewing on fibrous tubers to extract as much calories as possible, something that is completely unheard of in the industrialized world.

Cooking and food processing were important innovations in human evolution that allowed our ancient ancestors to broaden the diversity of their diet and extract more calories from the food they were eating. The problem is that we’ve now taken food processing to the extreme, thereby setting the stage for a range of mismatch diseases and disorders, some of which are related to dental health and the development of the jaws.

Toughening up our diet

It’s not just people who eat a processed, Western diet that should be worried that they’re not spending enough time chewing. In comparison to ancestral human diets, modern diets tend to be very soft. Not just because most of us prefer to eat tender meat and relatively soft and easy-to-eat food, but also because domesticated fruits and vegetables are higher in sugar and lower in fiber than uncultivated versions.

So, what can we do about this problem? One obvious solution is to include more tough, hard food into our diet – and especially in the diet of our children. To make a difference it probably has to be a fairly large quantity, not just a fibrous apple here and there. Chewing on gum is another strategy that could help children grow a bigger and stronger jaw.

Besides the importance of chewing on tough, hard foodstuffs, infant feeding practices, maternal nutrition, oral posture, and sucking habits the first few years of life are all important factors that impact dental health and/or the development of the face and jaws.

Picture: Creative Commons picture by clappstar. Some rights reserved.


  1. I appreciate this article in many ways, but what about the research showing that modern humans basically developed our brain capacity by inventing cooking, and thus freeing time that was spent chewing, reducing muzzle size and increasing brain size with more readily available glucose? Maybe the answer is somewhere in the middle, a wholesome whole food diet with cooking to improve digestion of many foods, but still including plenty of good meats, crunchy fruits and veggies, dense breads and no liquid calorie crap?
    Thanks again for the article 🙂

    • Hi Morgan!

      It’s correct that our ability to control fire, and hence, the invention of cooking, probably helped accelerate the growth of the large human brain. That being said, the weight of the evidence shows that the marked increase in human brain size began long before cooked foods started becoming an important part of the human diet. Cooked plant foods may have helped accelerate the evolution of the large human brain, but it was probably animal source food that was the key player.

      Moreover, when compared with contemporary hunter-gatherers, the vast majority of westerners eat a diet that is extremely soft and low in fiber. Hunter-gatherers eat a much greater volume of food, since most of the food they eat has a low energy density (when compared with the foods that make up “modern diets”).

      • I thought we westerners ate far too much? Low nutrition, high sugar/fat foods. Hunter gatherers surely had higher food value from the volume they ate? How do we know they ate higher volume than us today? Also …. the brain seems to have developed whilst the jaw/teeth deteriorates? What a cost! Slightly tongue in cheek but having a larger brain does seem to have had its downside! Perhaps it has come with the ego … which is not doing us any favours just now. I rather think that a smaller brain and healthier teeth might be a better option!

        • Hi Amanda!

          It’s important to differentiate between the volume/quantity of food consumed and the number of calories consumed.

          When compared with the types of foods our preagricultural ancestors ate, the foods that make up the typical Western diet have a very high energy density. In other words, when compared to modern people, our hunter-gatherer (HG) forebears had to eat a greater volume/quantity of food to get e.g., 2000 kcal. Also, keep in mind that HGs were more physically active than we are today, and therefore expended more energy every day (that needed to be replaced through eating).

          Just magine how much easier it is to get 500 kcal from for example ice cream than from fruits, veggies, or lean meat.

          You could check out these links for some more info on this topic:

  2. I know the chewing hypothesis is correct as I have seen some changes in the direction of reversing the vertical growth of my face (jaws moving forward, slight shortening and widening of my face and improved gonial angle-I now have about an inch of ramus length, whereas before I had none visible) due to chewing extra hard gum for 2-6 hours daily, along with learning correct oral posture and swallowing pattern, over the past 2 years. I saw more noticable results from chewing than oral posture in fact. I am an adult in my 20s, so for sure the results could be that much more significant in children whose bones are that much more malleable.

  3. I would associate the changes in the human faces more with the difference in nutrient density of the diets. How can you say that chewing is a factor when we are eating more meals now than our ancestors with foods that are not necessarily harder to chew than raw/lightly cooked animal foods?

    Here’s an example of a young child’s meal plan

    Breakfast: Cereal with pasteurized milk vs. Pastured heavy cream with wild berries

    Lunch: Peanut Butter and Jelly on Whole Wheat with potato chips vs. Raw Cheese and home made bacon on sourdough rye and some macadamia nuts

    Dinner: Fried chicken and waffles with biscuits vs. Pastured duck served with plum sauce and scallions

    I would argue that the modern american diet requires more chewing and that the main factor in facial development is fat soluble vitamin intake.

    • Hi Frank!

      Welcome to the blog.

      Poor maternal and childhood nutritional status (as well as a couple of other factors I mention in the article) also play a role in all of this. However, they are probably not as important as the reduction in masticatory effort and usage. At least we don’t have scientific evidence to say that they are.

      If I understand correctly, you’re saying that the modern american diet requires as much chewing as ancestral human diets (?). This is simply incorrect. A couple of points you should consider:
      -Uncultivated fruits and veggies are lower in sugar and a lot more fibrous than domesticated varieties.
      – Hunter-gatherers don’t eat nice, tender steaks. Rather, they typically eat the “entire” animals they kill.
      – Our primal ancestors used their teeth to create tools, clothes, etc.
      – Hunter-gatherers and non-westernized, traditional people didn’t have access to food processors, microwaves and all of the other machines and tools we now use to process our food.
      – When compared with modern people, Paleolithic humans ate more of their food raw.
      – Since a typical hunter-gatherer diet has a much lower energy density than the Western diet, hunter-gatherers have to consume a greater quantity/volume of food to acquire the same amount of calories as a westerner.

      Thanks for your comment!

      • Hi Erik I had considered many of your points in the past and here are my explanations.

        Fruit and vegetables aren’t what I had in mind; it was more of an example. The pre agricultural diet was primarily carnivorous, especially in early childhood.

        The inuits, for example, would use their tools to cut raw meat into small pieces, chew them several times for flavor, then swallow the whole piece. Chewing for them, if anything, is less than we chew meat now.

        Our ancestors did use their teeth to create tools and clothes but children were most likely not doing this, especially in every society.

        They had access to tools that can cut meat which is all that was needed.

        Raw meat is much easier to chew than cooked meat, especially in regards to tougher cuts.

        Calories in vs calories out is a bit different in the context of a hunter gatherer ketogenic style diet. When you use fats as energy and are active for many hours a day your body becomes much more efficient at using and conserving energy. I personally bartend for 12-14 hours straight on a similar amount of calories to what I was eating before as a sedentary person with little change in body composition.

        They were also not eating meals as frequently, which would probably result in even less chewing.

        • Seems like we have to agree to disagree here. I think it’s absurd to claim that the typical Western diet, which is high in processed foods containing starch, sugar, and refined fats and low in fibrous plant foods, is not a very soft diet. As I mentioned in the article, Dr. Mike Mew, one of the experts in this area, estimates that modern humans use the masticatory system about 3-5% of what Paleolithic humans did, and that’s before you consider non-nutritional exercise of the jaws (i.e., using teeth as tools to make clothes and weapons).

          I highly recommend checking out this review paper if you haven’t already done so:

          • This article is very interesting. Thank you. Frank, I also thank you for expressing your alternative thoughts on the matter in such a concise, thoughtful and polite manner. Expressing ones questions about certain points of content within an article like this leads to further discussion about the subject. Which can only be a good thing. I’ve enjoyed reading your thoughts and ideas and Eirik’s counter arguments. You’ve both given me more food for thought.

          • I have to admit I dont see much chewing going on with our Western diet ….. its pretty disturbing to watch kids and adults gulp food down as if they had the stomach of a dog ….

          • .. the photo above says it all too … how do you chew ice cream!!

          • So would you say that someone on a western diet who chewed gum all day would have similar facial development to an indigenous inuit who was chewing less but eating foods that were dozens of times higher in vitamins and minerals?

            Chewing might have some role in facial development, although I am still against it. But to say that vitamin and mineral intake doesn’t play a larger role goes against what I have assimilated from years of studying.

          • It’s difficult to say. As I mentioned in the article, there are several factors that play a role in all of this. A direct quote from the post:

            Besides reduced use of the masticatory system, other factors, in particular pacifier sucking, bottle-feeding, incorrect oral posture, and poor maternal and childhood nutritional status may also be important contributors to the high prevalence of malocclusion, crowded teeth, and narrow dental arches in westernized societies.

            The reason I chose to focus on chewing is that there’s solid scientific evidence to show that a reduction in masticatory effort and usage can promote the development of many of the disorders I talk about in this post. For the other factors I mention in the quote above, the scientific evidence is more sparse. I also felt the article would get too long if I were to cover “everything”.

            I don’t doubt that nutritional status plays a role in all of this. However, I’m inclined to believe that it’s not as important as mastication. Pacifier sucking may also be an underappreciated factor.

            Keep in mind, I don’t have a horse in this race. I have no intention of becoming a manufacturer of hard-to-chew baby foods 😛 I just convey the story as I see it.

          • “Although it still remains to be proven conclusively whether this change is attributable to masticatory stress, weaning behavior, or other demographic factors, it appears to act in a correlated fashion globally, causing a consistent shift toward a shorter, broader mandible.”

            This is simply agreeing with both of our points. The conclusion is that the indigenous lifestyle and diet results in improved health and better development in early childhood to young adulthood. (which is much easier to physically see and measure than immune system and metabolic function)

  4. Frank

  5. You mention infant feeding practices as a throw away comment in the last paragraph, but the lack of full term breastfeeding plays a huge part in this face chance, much more so than food hardness. We evolved to nurse for 2.5 to 7 years, not the days or weeks that is more common now. Breastfeeding issues 33 muscles, bottle feeding uses 3. The missing years of suckling make an enormous impact on health in general, including jaw and facial development.

  6. As a UK orthodontist who practices extraction free orthodontics, I entirely agree. Good article, Erik. If the teeth are “crowded”, correct the growth by orthopaedically correcting the the jaws first – it is not a mystery!!

    Interestingly I see the same issues in dogs – dried food [crackers by any other description] -v- a raw meat diet [ eg raw chicken on the bone …]

    • Thanks for your comment, Chas! Good to hear from an expert in the field. It would be interesting to hear your experience with preventing and/or treating the disorders I talk about in this article.

  7. Frank,
    I am due to talk on this very issue at the Ancestral Health Symposium in Denver in August. They have asked if we could arrange a panel to discuss the relative contributions from content and constituency of food in their relation to malocclusion. As such I am looking for someone to defend the content argument, can you think of anyone?

  8. Hi Eirik,

    I suffered an enormous pleasure while I read each line of your article.

    I work with my father on his investigations, the central issue of his lifetime studies, are based on what you´ve written on your blog: human evolution, retrognathism, civilized diet (soft food), same number of teeth with less space for the free and normal movements of the mandible, lack of space.

    We hold, that civilized diet takes us to the point of suffering what we call “La Enfermedad de la Evolución del Aparato Masticatorio Humano” (The Human Masticatory System Evolution Decease) which consists on two main pathologies, one traumatic and the other due two soft diet.

    Our site is, sorry but it´s only written in spanish.

    Here´s an english article about our investigation in english:

    ¡Thanks and you have a new subscriber!

  9. The lack of facial development that has occurred in relatio to the change in our diet is related to genes for facial development that have not been expressed. Wearing an intraoral dental appliance (Homeoblock) at night has been shown to increase mid face volume in so called “non growing adults”. The appliance has a patented unilateral bite block that provides compression and strain on the cranial sutures while signaling the periodontal ligament. The result is upregulation of genes for facial growth resulting in larger jaws and wider faces similar to our ancestors.

  10. Cian O'Meara BDS says:

    Something to bear in mind when chewing gum; the act of chewing stimulates saliva secretion and in turn the secretion of gastric juices. I’ve always felt dis-inclined to recommend chewing gum to increase salivary production for the sake of caries prevention and indeed for possible stimulation of the growth pathway in the jaws. Confusing one’s digestive system (turning it on but not presenting food) in such a manner may give rise to other issues … Be sure paleolithic humans went hungry for long periods of time too!

    Good article and there’s a whole lot more in this area (the environmental stimulation of human growth). Malocclusion isn’t the only disease of civilization!

    • Excellent points, Cian!

      There are always some downsides to consuming evolutionarily novel “man made” food products. As you point out, chewing gum is not exception.

  11. This is so true…. but the articles misses and important point… that is that the Western diet also is inflammatory in nature and this inflammation may play a significant role in illness which can lead to the habit of mouth breathing – which in turn has a perhaps even greater impact on creating a long face and dental crowding

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