Nose to tail nutrition and evolution

Heather Rosa, Dean, Institute for Optimum Nutrition

Published in JHH16.3 – The Real Food Issue

Food was the key to my recovery from illness and my inspiration for studying nutritional therapy. It has since kept at bay Barker’s baby trajectory1 and helped me survive 30 years in academia. Having surmounted the usual zeal to find the perfect diet I now have sleepless nights pondering complexity! I’m endlessly fascinated by the web-like interconnections between health, dis-ease, food, beliefs, movement, evolution, genes, microbiota, individuality, community, environment, politics…As Dean of the Institute for Optimum Nutrition my goal is to educate nutrition scholar-practitioners, instilling critical thinking, evidence informed and collaborative practice. I’m half Italian, grow organically, forage, and eat chicken feet!


What do we mean when we speak of ‘real food’? The simplest of food is complex. We eat combinations of food – more complexity. We are complex and the environment in which we eat and live is complex. The impact on health of what and when we eat is influenced by individuality, belief, community, environment, access, politics etc. We no longer eat to survive. The diversity of food eaten in the UK has diminished. Now place all this complexity and lack of diversity over a lifespan of continual change and challenge. This complexity often appears insurmountable, for there are so many confounders on the food journey from soil/sea to self. Research underpinning current public advice sits on shaky foundations, poor methodology, and bias, both personal and commercial. For the public this leads to confusing messages and reversals… welcome back to butter!

Where nutritional considerations collide with concerns about environmental sustainability, ill advised future diets (EAT-Lancet, 2019) may be proposed. Research methods including randomised controlled trials are inadequate in the face of such complexity, but new research paradigms and methodologies are emerging – genome, epigenome, microbiome and exposome research. However we cannot wait, we need a consensus on a definition for ‘real food’ that takes into account at least genetic adaptations, human physiology and biochemistry and health status.

There are no simple messages in nutrition, however an ideal food/diet should both sustain reproduction and health throughout the lifespan and be regenerative for the environment. We can apply principles of holism, food diversity and evolutionary theory, and take into consideration current advances in genomics, epigenomics and our understanding of the microbiome, while remaining open to challenging these frameworks as we discover more through new research and experience.

Food is medicine –nutrigenomics and the microbiome

What is ‘real food’? One answer is that ‘food is information that tells your entire biology what to do and when to do it, but junk food is like malware on your computer: scrambled information that leads to a major hardware crash’ (Frank Lipman, 2019) The substances in food change the environment in the gut. Food speaks to our gut microbiome which in turn speaks to the whole body. Food influences the expression of genes. Microbes, for example, train the immune system
via conversations with Regulatory T cells (Treg cells) which by restraining inappropriate immune responses in the healthy gut have a central role in the maintenance of intestinal homeostasis (Spector, 2016). Not eating reduces microbial diversity however, yet short-term fasting can be beneficial as long as non-fast days contains a diversity of nutrients dense foods.

Nutrient-dense foods contain vitamins, minerals, complex carbohydrates, lean protein, and healthy fats. Examples of nutrient-dense foods include fruits and vegetables, whole grains, low-fat or fat-free milk products, seafood, lean meats, eggs, peas, beans and nuts.

We now understand that it is not just vitamins and minerals conversing with our genes and microbes. There are myriad other substances in food that also communicate, such as phytochemicals (think rainbow), nucleotides (found in organ meat), short chain fatty acids (eg butter, coconut), fibre, hormones, bacteria and bacterial fragments (fermented foods), fungi, viruses and as yet unknown beneficial factors as well as xenobiotics introduced in the growing, processing and preserving of food. The context in which food is eaten, lifestyle and environment, are also important. So, we could add to our ‘real food’ definition foods that speak beneficially to both our microbiome and to our genes. There is still much to learn about these interactions. However, generally research shows a rich diversity of whole, nutrient dense (important if a person is intermittent fasting), minimally proceeded food, low in xenobiotics keeps these conversations healthy (Spector, 2015).

Evolution: an ancestral approach

Diet, and the use of fire for cooking, has been cited as a driving force in human evolution (Cornelio et al, 2016). Associated physical changes included increased brain size, a reduction in gut length and blunter teeth. For our preagricultural, hominin ancestors’ nose to tail consumption of fish, seafood, animal foods and insects became the dominant sources of energy, protein, long chain fatty acids, iodine, vitamin B12, taurine, haem iron and zinc. Brain development occurred alongside an abundance of essential fatty acids (EFAs) from aquatic, and animal fatty tissues (brain, bone marrow etc). Humans are inefficient in the conversation of plant rich 18-carbon fatty acids (seeds, nuts) into the 20- and 22-carbon polyunsaturated fatty acids (EPA and DHA) essential for cell membrane
function and brain tissue. This conversion is further hampered by high n-3 and sugar intakes, type 2 diabetes and subclinical deficiencies in B6 and zinc co-factors in the conversation pathway.

What are humans adapted to eat?

Necessitated by migration, biological adaptations over time have expanded dietary patterns for some populations: eg milk (lactase) and grain (amylase). However, there are no known non-animal food civilisations perhaps because such a diet would provide inadequate energy return for survival. It has been argued that divergence from our evolutionary dietary pattern involving high meat intake (fat and protein) to a more grain and processed foodbased diet, forms the basis of lifestyle-related chronic diseases (Mann, 2018).

We can’t go back in time and eat the foods our ancestors ate, nor know fully the extent of their dietary intake and patterns of eating. However, we evolved with
certain nutrient needs. Could we define a ‘real food’ diet as one that meets intra-individual requirements for physiological, psychological and anatomical needs across the lifespan, without the need to supplement (eg B12) or fortify the food?

Quality, as well as diversity and quantity, is another important factor to consider in defining ‘real food’. Quality of food is impacted at multiple points along the journey from soil/sea to self. For example what we feed animals becomes us: something worth remembering when advocating nose to tail eating. Soil nutrient content and whether to supplement micronutrients is another significant topic.

Expanding the diversity of ‘real foods’ in the diet

Dietary diversity and quality

Today we eat fewer than 20 separate food items a day, from just four main ingredients wheat, corn, soya or meat, mostly processed, and with high glycaemic potential to elevate blood sugar. The fossil records and observations of modern hunter-gather tribes, suggest a broader diet could contain over 150 foods a week, mostly animal with plants playing an important supplementary role (the Hadza of Tanzania have access to around 600 plants and animal species [mostly birds] [Spector, 2017] and insects). These foods came whole, not as juices and certainly not fractionated (eg high-glucose corn syrup) or highlyprocessed. Foods were seasonal, local and fresh, eaten raw and cooked (meat and starchy tubers). Preparation methods (increasing in diversity and complexity over time) included cutting, chopping, soaking, cooking and preserving (air, sun or with naturally occurring materials and later fermenting).

It is not only ultra-processed food that we need to beware of in defining what real ‘real food’ is or isn’t. We also need to understand that many of the fruits and
vegetable we eat today bear little resemblance to those eaten by our ancestors. Selective breeding has increased their sweetness and reduced numbers of seeds, phytonutrients and fibre content making these foods relatively easy to consume in large amounts.

Tim Spector who lived three days with the Hadza reported: ‘My next snacks were wild berries on many of the trees surrounding the camp – the commonest were small Kongorobi berries.These refreshing and slightly sweet berries have 20 times the fibre and polyphenols compared with cultivated berries – powerful fuel for my gut microbiome.

The low glycaemic index of ancient/wild/bush carbohydrate foods places a relatively low demand for insulin secretion potentially protecting from a genetic predisposition to insulin resistance and the consequences for developing chronic diseases (Brand-Miller and Holt, 1998). So can modern plant varieties be classed as ‘real food’? Would the public be prepared to eat wild/bush varieties?


Analysis of fossilised faeces suggests our early ancestors routinely consumed a wide diversity of insect species — ants, beetle larvae, lice, ticks, mites, and spiders well before we early hominids began to hunt or farm. When the Hadza eat honey they also eat fat and protein from larvae, pupa and insect parts (Marlowe et al, 2014)

It is estimated that as much as 80% of the world’s current population eats insects intentionally. Whether wild and collected or farmed, this extends to over 1,555 species of insects and spiders. However 100% of humans eat them unintentionally according to Srivasta et al (2009). Do you like chocolate? Chocolate averages 60 to 90 or more insect fragments per 100 grams. The food colouring cochineal is made from the eggs of pregnant beetles. Honey is the by- product of insect activity. For those of you who like smoothies, up to 60 per cent of frozen berries can be mouldy, with an average of four or more larvae, or ten or more whole insects, per 500 grams. I like to forage so I’m lucky I’m getting more! Can any plant-based diet be truly vegan?

Humans eat two classes of invertebrates: mollusca (shellfish), and arthropoda (insects, crustaceans, scorpions, spiders etc) (McGrew, 2014). Somewhere back in time insects became the enemy, probably when farming invested in livestock (Gordon, 2013). Prawns are generally eaten without a second thought, although this was not always the case. Witchetty grubs can be thought of as land prawns, but our distaste for them is an issue, since insects are nutrient dense, and proportional to their macronutrient composition, they could serve as equivalents not only of wild meat, but of a range of other foods including some shellfish, nuts, pulses, vegetables and potentially fruits (McGrew, 2014). As a solution for food and feed security, they contain 60% protein per 100g. Compared with producing meat, where 100 gallons of water creates 6g of cow protein, or 18g of chicken protein, the same amount of water can turn into 238g of cricket protein ( Utilising insect powders, pastes, liquids and oils may be a way to surmount barriers to diversifying our diets with insects, a rational argument – but without a sustained change in attitudes and habits, we will need many more creative solutions.

Insect farming is a massive industry in the far east. European production is small, producing niche costly products (Dossey et al, 2016). Environmentally there are questions about the cost of energy needed to maintain growing temperatures. Grain and high-quality meat are used as feed. In the UK EU laws regulating animal feed don’t allow the use of food waste to be used as animal feed. In short there is no such thing as a free lunch! Quality is an issue. As with salmon when insects are farmed and fed a cereal-based diet their n-6/n-3 ratio increases significantly and are not considered supportive of human health (Oonincx, 2019). Current consumption of n-6 is already considered excessive and potentially detrimental creating a pro-inflammatory state in the body. The optimal ratio may vary with the severity of a disease resulting from the genetic predisposition (Simopoulos, 2008). A more desirable n-6/n-3 ratio can be obtained by enriching standard insect diets with 1%–2% of flaxseed oil or chia seed oil (Oonincx et al, 2019.) Fat is in the form of ALA and not EPA. DHA is not retained in insects. Human conversion of ALA to EPA is inefficient and reduced further in type 2 diabetes.

Insects provide natural nutrient dense, minimally processed food sources for humans but is this ‘real food’ if the insects are not fed their natural diet? While insects can provide lower energy and resource intense sources of protein, fish and shellfish remain the better sources of EPD and DHA in the human diet.


It is not just the quantity but the quality of food we consume that confers health. Humans can tolerate a wide diversity of foods, but it appears we have not evolved to thrive on a diet high in ultra-processed foods, sugar and damaged seed oils nor are we likely to. Avoiding these foods is an easier message. More problematic is what we advise on foods that are perceived as healthy yet may, through hybridisation, breeding and other insults on the journey from soil/sea to self, have a low nutrient density and less fibre, are higher in sugar and whose essential fatty acid profile is skewed.

Eating nose to tail is to be applauded for providing increased nutrient density and the benefits of non-nutritive health-giving compounds. While including insects in the diet could improve available nutrient density, it might not provide the touted solution to future world food supply unless insect farming practices embrace sustainable and regenerative principles.

The frameworks briefly explored here provide reasonable starting points for defining ‘real food’. Still, individuality (eg of the genome and microbiome) and food’s biological and cultural complexity will mean that no simple universal nutrition message is possible, and especially so for those with chronic ill health. Nevertheless, any diet that encourages eating a diversity of nutrient-dense wholefoods both animal and plant, minimally processed to enhance nutrient availability, has to be the basis for any real food project to begin with.


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