Have humans lost the ability to choose nourishing diets or has it been hijacked? This question posed by emeritus professor Fred Provenza emerges after comparing findings from his 40 year career in livestock nutrition to human nutrition and is highlighted in his 2018 book Nourishment: What Animals can teach us about Rediscovering our Nutritional Wisdom.
As New Zealand farming gets squeezed by environmental compliance and synthetic foods Provenza’s insights offer new directions to excite farmers and their roles as the nation’s food doctors. He highlights where farming provides insights into human nutrition research to ensure its role as a cornerstone of civilization in this view presentation.
Provenza recalls the question that got him started in livestock nutrition, not what livestock ate but how they knew what to eat, what he calls nutritional wisdom of the body. “Nobody tells a bacteria or wildlife how to eat, grow and replicate. Even lab rats can self-medicate their own diabetes without our help. Yet the most intelligent species on the planet has to be told by authorities what to eat”. Provenza thinks this ironic.
Humans forage in supermarkets among many potentially toxic items appearing as nutritious but these foodstuffs can be deadly. This echoes Wendell Berry’s “people are fed by a food industry which pays no attention to health and treated by a health industry that pays no attention to food.” Wild herbivores, omnivores, and carnivores have the same issue in their environments but are much better at navigating their diets than humans.
There are three keys to understanding wisdom of the body; flavour feedback loops, satiety and variety, and socio-cultural landscapes.
Understanding Flavour Feedback Mechanisms
Wild herbivores will eat up to 100 different foods selecting for what they need, but at any one meal the majority will be 4-5 foods. Provenza’s work started with the question how did herbivores know which foods addressed which issues in their body?
With humans taste determines opinions on food; favourites always taste better, anything avoided is yucky. But there is more to nutrition than taste. Our body responds to demands for primary (carbs, protein, fats, minerals, vitamins) and secondary compounds (alkaloids, phenols, turpenes) driven from a cellular level. Cells can only access nutrients delivered by blood capillaries so their experience determines which taste buds get activated. But it’s not just our cells but gut bacteria cells which also drive this feedback mechanism.
This phenomenon goes well beyond what reductionist science can currently accommodate. When selecting from an array of foods livestock choose diets to improve health and production. They balance protein/carb ratios and select combinations to correct mineral imbalances through auto mechanisms that do not require conscious thought.
Animals also self-medicate. They learn to identify which plants and resources address different aliments; tannins for bloat, bentonite for acidosis, terpenes and alkaloids for internal parasites. Neurotransmitters and hormones govern feedback responses. Livestock ways of balancing the whole complex show is beyond what reductionist science can demonstrate.
Humans have this ability too. People on lean meat diets develop high cravings for fat because lean meat doesn’t have all the fat soluble nutrients including those amino acids required to breakdown red meat itself.
However, the way livestock scientists determined these findings is similar to how our processed food industry develops products. Corporations know to make food desirable is by isolating compounds which drive cravings. It’s no different to how cocaine creates addiction whereas chewing cocoa leaves does not. Its dose and rate of release determining toxicity.
Corporations target youngest age groups with familiar foods and flavours and lace them with the most addictive of hits, sugar. These cravings can be initiated in the womb. Pulses of energy create addictions by lifting refined carbohydrates to drive high insulin switching cell mitochondria from burning fatty acids to glucose. Even when lab rats have equal access to cocaine and sugar, it’s sugar they crave.
So while misuse of this insight is well documented it’s how humans use feedback mechanisms to improve their own health which should govern food production. Pets and livestock provide daily examples yet little if any scientific funding is channelled here.
Satiety, Variety and Diversity
The idea diversity and adventure is the spice of life is true. It’s thought livestock and wildlife eat a wide range of foods for three reasons; no one plant contains all nutrients these animals need, secondary compounds limit how much of any plant an animal can eat, and when the mix of primary and secondary compounds meets cell demands, that triggers a deep sense of satiety. Furthermore, animals get bored of eating the same foods. This is why landscapes with a diverse range of plants are ideal.
Livestock will overeat foods to achieve desired levels of nutrients. They will do this willingly even to the extent of poisoning themselves with another compound. This is evident with highly fertilised pastures where animal graze all day and seldom settle to ruminate because an excess or deficiency of one nutrient drives hunger. Satiety eliminates this behaviour and occurs consistently with a diversity of plants.
Most human research focuses on single compounds and foods, seldom combinations or sequences of foods. Studies show which foods are high in protein, fibre, and phytochemicals but which combinations of foods create satiety? An example is garlic. A clove of garlic will have over 200 compounds, a garlic tablet might have a dozen. Lower quality foods that lack nutrients drive greater quantities consumed; how convenient for food industry commerce. It’s relationships between compounds that makes the difference.
Looking at culture of nutrition Provenza argues humans should focus on how their bodies respond to combinations of whole foods rather than silver bullet compounds within foods. Food order within human meals can reduce glucose-insulin responses; wine prior to a meal reduces GI by 15%, organic acids such as vinegars and their salts lowers GI, eating foods high in fat or protein prior to carbohydrates lowers GI, salad compared to bread as an appetiser produces a lower GI response, and eating high carbohydrate desserts at the end of a meal is also good practice.
Meal sequences also impact GI over the day. A hearty high energy breakfast (including fats) followed by a low energy dinner (salads) increases insulin sensitivity and satiety while reducing food intake.
Research regarding human meal combinations is minute compared to livestock and yet the focus of livestock nutrition research is eating more to increase performance. Its focus on primary compounds misses roles secondary plant metabolites play in satiety and taste.
Provenza asks what about eating less and maintaining performance. When bodies are satiated they requires less food because nutrition demands are being met.
When research fails to investigate we have to look to farmers to fill that gap; alpine herders in France for example. They know grazing sheep on lucerne and birdsfoot trefoil for 30 minutes results in greater consumption of tall fescue because tannins bind up tall fescue alkaloids. This understanding is how their livestock outperform academic calculations and is seldom considered in total mixed rations (TMR).
Drawing on Mark Schatzker’s work and his book The Dorrito Effect, modern human food has changed in two ways; real food flavours have got blander and now we add synthetic flavours to improve taste. This has made junk food more desirable. Look at any old cookbook, the old recipes seldom include loads of spices because meats and vegetables had plenty of taste.
Studies of dairy products comparing phytochemical richness find Europeans prefer cheese made from cows grazing pastures verse barn fed TMR. At French country fairs farmers will go around sampling each other’s wares to appreciate different flavours even if it’s just over the fence. Location provides unique signatures for the palate. The French populace have never been into nutrient fads.
Food scientists are now making connections between disease and phytochemistry despite their industry’s only interest is increasing consumption. Seldom are sources of red meat explored as that can impact health. For example, humans exhibit significantly higher inflammation responses after they’ve eaten beef fed TMR in a feedlot than eating kangaroo that browsed on diverse bush tucker. Inflammation is the precursor to disease, especially cancers, heart disease, and others.
The emphasis on quantity of food over quality results in decreasing nutrient density. Provenza highlights a study revealing from 1950 to 1999 the richness of 43 human foods declined from 10 – 50% in 50 years highlighting the legacy of agricultural science. Pouring sugar over greens children refuse to eat misses the point. Nutrient density drives flavour.
Soil health and function contributes greatly to plant species richness and quality. The ability of plants to source nutrients within soil profiles affects their chemical make-up. That affects flavour. It’s why restaurant salads include deep tap rooted dandelion leaves but not shallow fibrous rooted perennial ryegrass.
Accelerating pasture and crop growth with irrigation and soluble fertilisers reduces nutrient density resulting in inferior products. It’s why excess urea causes so many health and production problems, especially in dairy. Harvesting foods before they are ripe also reduces nutritional density. We also breed plants for growth and not phytochemical richness reducing overall quality and flavour. Author Jo Robinson highlights this practice going back 6,000 years in Eating on the Wild Side. No matter how they’re produced, flavourless foods are not healthy nutrition.
Meat raised on a phytochemical diet has a completely different and more healthy nutrient profile than one raised on TMR. These chemicals are stored in fats and are how populations like the Inuit thrive without access to green plants.
Furthermore, not only do landscapes impact our responses when consuming foods, but whole ancestral histories. The knowledge animals have of what to eat is passed down from their ancestors through their mothers. Its experiences as babies that are critical for thriving populations and that our preferences may have more to do with grandparents than parents.
This point leads us into the field of epigenetics – how environment affects genes and gene expression by influencing form, function, and behaviour. Provenza observes in sport we call it home field advantage. When livestock are left on their mothers longer they learn which plants to eat and avoid in the landscape in different seasons. Those experiences start in the womb, drinking mother’s milk, and mothers as a role models to demonstrate what to eat. That creates greater adaptability later in life.
Lambs and calves experiencing mature pasture will utilise those pastures later in life with more efficiency, weight gain, milk production, and get pregnant sooner than livestock raised on high quality diets instead. Cattle exposed to straw at two months of age and reintroduced to it five years later consumed it with greater gusto and efficiency than cattle that had never seen it. The offering of straw at a young age switched on the right genes to broaden the range of feed they could eat with confidence later in life.
Another livestock experience comes from Australia regarding saltbush. Lambs whose mothers grazed saltbush while pregnant grew faster and performed better grazing salt bush than counterparts without that experience. Local is better adapted to local circumstances.
It also happens with plants. Grain researchers are discovering how seeds replanted in the same field lift yields without any other amendments. It appears parent plants enhance traits in their seeds for their location. They invest in genes to optimise effects of local conditions.
Just how intertwined and complex effects of locality and culture are demonstrated with organ transplant patients. Taste receptors are not just in the mouth, they are found in every organ throughout the body. This explains why patients with donor organs experience desires for foods they never had cravings for but their donor did. Location embeds food preferences through genetic make-up.
Your culture largely determines what foods you eat. Yet even within cultures, diets vary from place to place so there is no such thing as a defined Mediterranean diet for example. Research shows that no matter what kind of diet, individuals respond differently; some gain weight while others lose weight on the same diet. There is no such thing as an average diet which suits everyone. This is why wisdom of the body is so crucial and that humans have the ability to tap into it.
Provenza brings to life research of Clara Davis, a Canadian paediatrician who conducted an incredible study in the 1930s. Davis was a strong believer in the wisdom of the body, so much so that she organised a group of orphaned babies to choose their own diets from a buffet of 34 wholesome foods; none were processed or purified. No child ever chose the same meal in succession and no two children picked the same combinations of foods. A surprise was they even selected the right foods to rectify disease such as rickets. The experiment continued for several years because it was evident that babies were healthy picking their own foods. These foods represented a diet similar to primitive people’s diets which are shown to be sound because of their excellent nutrition. Culture is key to transfer knowledge.
Anthropological studies show native communities understood the role of food in reproduction by ensuring both parents were given good nutrition prior to conception, during pregnancy, and lactation to guarantee nutritional wisdom was passed on to next generation. Compare that diligence to today’s supermarket offerings driven by corporate and academic politics whose legacy is epidemics of chronic diseases like inter-generational obesity; fat mothers make fat babies which make fat mothers.
Provenza’s message highlights the discourse between real human nutrition and our modern world of food production. Forget all media advice; simply expose yourself to a variety of foods and trust wisdom of your body to select what it needs. The conflicting and incomplete information swirling around health benefits is more confusing than no knowledge at all.
As science digs deeper into nutritional disciplines and associated subjects, it overlooks wisdom of the body as driver of all these processes and insights. Unlike livestock research, no mention on nutritional wisdom of the body is ever made or referenced in all of the information Provenza reviewed on human nutrition. Could this insight be agriculture’s unfair advantage?
Imagine if Lincoln and Massey Universities reorganised their institutional purpose based on nutritional wisdom of the body? How would that change our perception and understanding of farming? The story it would create would put real agriculture back on its pedestal, move synthetic foods to courtrooms, and have a ripple effect throughout the health sector, particularly mindfulness of the general population. Finally farmers would continue to prove how ecological doctoring using technology, livestock, and crops for rejuvenating landscapes and communities that populate them is the cornerstone of civilisation.