Should we switch to plant-based proteins?

While New Zealand was in lockdown, I had ample opportunity to think about life, the universe and everything.  Specifically, I was thinking about plant-based protein as human food.  Recently, meals at home have exposed me a variety of new dishes and some of these were plant-based.  I’m setting out these thoughts in the hope that they will stimulate conversation between readers.

First, there is a strong drive from some members of the community to change from eating animal proteins to eating plant-based protein meals.  Some of this is a concern for the welfare of animals and some is ideological.  Probably the primary driver is health, but the second driver is sustainability and environmental concerns around our planet and its long term health.  Is it really more healthy to eat only plant proteins?  Is it truly better for the environment?  There is concern that rivers and waterways are being polluted by our raising of animals for meat and milk, but will the production of plant proteins result in greater use of fertiliser and hence increase runoff?  Methane emissions will decrease, but growth of legumes may ultimately result in increased nitrate leeching. Of course, traditional farming mixed plants and animals - the vegetables etc. were grown on land fertilised by animal manure, but if we no longer raise animals, that cycle will be eliminated. 

What is the point of trying to reproduce the taste, appearance and texture of products such as burgers, but using plant proteins?  Really, that is just a sop to confirmed meat eaters.  As I understand it, The Impossible Burger is more expensive to produce than the meal it is trying to emulate.  Is there going to be resistance to the use of colours and flavours to simulate animal products?  The key ingredient that gives the Impossible Burger its meaty taste and makes it bleed like meat when cut is soy leghemoglobin, derived from genetically engineered yeast.  Production of the yeast by fermentation requires inputs of industrially manufactured, chemically synthesised ingredients.  The safety of these inputs will be subject to regulatory approval and their use will not be universally accepted.  Ikea is introducing a non-meat version of its traditional Swedish meatball  and claims that conversion of about 20 per cent of its meatball sales to plant balls would mean around 8 per cent reduction of the climate footprint for the food business at Ikea.  Meanwhile, KFC has announced that it is collaborating with 3-D Bioprinting Solutions to develop chicken nuggets made with cultured chicken cells and plant material.  The thinking of food technologists and new product developers is way ahead of the general population.

We all require iron in our diets, young or pregnant women particularly.  The recommended daily allowance for vegetarians is 1.8 times higher than for people who eat meat. This is because heme iron from meat is more bioavailable than non-heme iron from plant-based foods, and meat, poultry, and seafood increase the absorption of non-heme iron. This is just one aspect of changing from eating animal protein to exclusively plant-based protein.  There is any amount of information on the Internet regarding iron requirements and sources, but caution is required before believing everything!

I really have no answers for these questions, but I think that the proponents of moving to an exclusive plant protein diet haven’t thought it through.  Here are some questions that I’d like answered:

Does New Zealand have sufficient agricultural land to produce all the plant protein we need to feed the population, assuming that we all move to consuming it?  Much of our farming is on hill country.  This is not suitable for crop production.

Will the energy inputs for food production increase or decrease?  We will need diesel to harvest the crops and energy to dry some of the products.  With the shutdown of the Tiwai Point Aluminium smelter, there may be an opportunity to divert some of the surplus electricity to processing of plant proteins, but will that be enough or even practical?

What of our exports?  In 2019, dairy, eggs and honey earned NZ$16.3 billion and accounted for 27.9% of total exports, while meat earned NZ$8.03 billion - 13.9% of total exports.  If meat and dairy were no longer produced here, that would be a loss of nearly 42% of our exports.  In the current post COVID-19 era, it would be hard to replace those contributions.

At what point do we start to trust scientific opinion?

I have spent quite a bit of time recently trying to sort out the difference between demonstrable scientific fact and informed scientific opinion.  An example of the former is the measurement of 'g', the acceleration due to gravity; the latter might be the opinion of medical practitioners and nutritionists that consumption of large amounts of saturated fat can lead to heart disease.  Few people would argue about 'g', but there is much discussion, even amongst the experts, about the effects of saturated fat in the diet.  An opinion gains validity when, if challenged, it can be supported by peer-reviewed research.

Of course, it is impossible to prove a negative, but at what point do we say "The overwhelming evidence indicates that ..."

At what point do we trust the opinions?

I found the following graphic on-line.  Click on the image to see it full size if it doesn't display properly in your browser.   I was surprised at how many learned groups had made these opinions known.  I am not going to state my own opinions here - I don't consider myself an expert in the field, but my training as a scientist does allow me to evaluate evidence provided to me in peer-reviewed literature.  It would be a very long stretch to claim that all of these individuals and groups were either supported by, or influenced by the companies producing GM foods.