Written by Dr Jacqueline Rowarth, Dr Ants Roberts and Mike Manning

Provocative headlines are part of modern-day living, but what’s the truth when it comes to alternative proteins? In a recent paper, Dr Jacqueline Rowarth, Dr Ants Roberts and Mike Manning explored claims that dietary shifts will reduce climate change, finding that if veganism is the new future, not even the vegans would be better off.

We’ve seen a lot of headlines and hype regarding the environmental damage that animals are thought to do to the planet and, as a consequence, increasing suggestions that veganism will save the planet. So, it isn’t surprising that farmers feel confused about what to do, while national and local government have been pushing for change.

In the Waikato, for instance, the regional council (via a report from AgFirst 2016) (1) has suggested that dairy, sheep and beef land uses could be more profitable (and with lower environmental externalities) under dairy goats, dairy sheep, gold or green kiwifruit, apples or chestnuts. Furthermore, the plant-based alternatives being suggested require suitable cropping land and environments, which cover fewer than 200,000ha of New Zealand.

Importance of protein and dietary choices

Most people recognise that animal-based food is part of a human diet. Research has shown that animal food allowed evolution of our large and complex brain, enabling us to become large, active and highly social primates (2).

However, ongoing statements that plant protein is just as good (3) is eroding that understanding. In addition, statements from high profile activists that we must become vegan to stop climate change and save the planet is having an effect. People are changing their diets – but the climate change effect is not as big as they think.

Research around diet is self-reporting and although vegan groups suggest that “As many as 6% of US consumers say they are vegan”, the range of estimates in the same article is 2–6%. Later the article states the number of vegans in the US has increased by 600% since 2014(4). Exaggeration leads to confusion; journalists can pick on whichever figure they like, point to the source and be right.

New Zealand is not immune. In 2019 headlines, including “Why 33% of New Zealanders are ditching meat” was based on a report for Food Frontier (5), an independent thinktank on alternative proteins. Just over 1,000 people were surveyed, and the report indicates 31% of people were flexitarian (eating what they want when they want) or “Meat Reducers”. A further 3% were vegetarian or vegan.

Research in 2018 surveyed more than 47,000 New Zealanders, finding approximately 94% still ate meat and fewer than 6% were vegetarian or vegan. Longitudinal analyses further revealed that the probability of shifting from an omnivore diet to a vegetarian or vegan diet over a one-year period was low (fewer than 0.6% changed to vegan and just under 1% became vegetarian). In contrast, almost 30% of vegans changed diet between 2017 and 2018, with slightly more becoming omnivores than vegetarians (6).

Plant-based and cultured protein

Vat fermentation for culturing protein has been proposed as the biggest threat to ruminant farmers, with its claims of vastly reduced environmental impact. However, like “plant-based proteins” most of the claims are hype. Analysis by non-profit investor network Ceres (8) has shown the claims made, whether by plant-based or fermentation companies, are based on the environmental impact of the company alone, not a complete life-cycle analysis which would include the supply chain and waste. All the alternative protein companies rely on crops, either for the substrate of their processing (e.g. potatoes, rice, pumpkin, pea isolate) or the energy to drive the fermentation (usually corn syrup or sugar cane). Consequently, all plant-based “alternative proteins” require land to grow the component crops, and crops require agrichemicals and fossil fuel to drive tractors, harvesters and for basic processing.

Meat

Beyond Meat, which describes its products as “plant-based, vegan meat that’s tasty and better for you and our planet”, discloses nothing. Impossible Foods claims that eating the Impossible Burger will reduce your environmental footprint through reduced water (87%), land (96%) and lower greenhouse gas (GHG) emissions (89%) in comparison with a bovine burger. The figures are not supported with data. The Ceres 2018 report ‘Measure the Chain: Tools for Assessing GHG Emissions in Agricultural Supply Chains’ (9) estimated that more than 80% of the emissions generated by food systems stem directly from agricultural production and its associated land-use change. Most food and agricultural companies consider these emissions to be “scope 3”. They are upstream or downstream emissions not under direct control of the company (indirect emissions) and are not included in their impact and ‘savings’ statements.

Cultured meat presents itself similarly. Memphis Meats (10) states that it is making meat in a new way: “One that satisfies our cravings, our conscience, and our heart.” Memphis Meats is still at the pilot stage but claims (through investor Richard Branson) that cultured meat will use much less water, land and produce up to 90% less GHG than conventionally produced meat. No data are available to indicate how, and questions are being asked (11).

The problems of scaling up cultured meat have been examined by the Good Food Institute. Meeting 10% of the world’s meat demand, estimated at 40m metric tonnes by 2030, would require 4,000 factories each costing around €382 million and housing 130 x 10,000L stirred tank bioreactors, each of which would be associated with 4 x 2,000L perfusion tanks. Each factory would need to be able to host 2,300,000L cell culture. The current largest facility hosts 250,000–350,000L cell culture (12).

The energy costs of maintaining a controlled environment and creating vats for fermentation are significant, and the energy for fermentation must be provided by something – sugar is the cheapest option, and sugar, whether from maize, cane or beet, requires agrichemicals and fuel. The impact of the overlooked factors could last much longer in the atmosphere than the methane from ruminants, the effect of which has gone in a few decades.

University of Oxford physicists have suggested that “under continuous high global consumption, cultured meat results in less warming than cattle initially, but this gap narrows in the long term and in some cases cattle production causes far less warming, as methane emissions do not accumulate, unlike carbon dioxide” (13). The authors identified a need for detailed and transparent life-cycle analysis (LCA) of cultured meat production systems and concluded that the relative impact of cultured meat will depend on the availability of decarbonised energy generation and the specific production systems that are developed.

Milk

Milk from dairy animals contains nutrients and processing is required to ensure human safety and product stability. Most of the plant-based alternatives contain additives to boost their nutrient content and stabilisers to prevent the additives from settling out.

Perfect Day has given up on creating milk through vat fermentation and is now trying to perfect ‘dairy’ ingredients, with success achieved using genetically engineered fungi to produce milk protein for ice cream. Other companies (TurtleTree and Better Milk) are in the initial stages of engineering mammary cells from humans and cows. This approach has similarities to cell-based meat and is likely to meet the same acceptance challenges identified by Pakseresht et al. (14).

Bio-availability and anti-nutritional factors

In plant-based proteins, essential amino acids (particularly lysine, leucine and choline) or EAA for human nutrition are in poor supply. Milk has a Protein-Digestibility-Corrected-Amino-Acid-Score (PDCAAS) value of 1, which indicates that all the protein (3.7g in 100g) is nutritionally available. Beef has a PDCAAS of approximately 0.92 whereby 100g raw steak contains 18.4g usable protein. In contrast, quinoa and rolled oats contain 11.9 and 9.6g of usable protein per 100g dry. A bowlful of either, once cooked, is not as protein-rich as first glance might suggest.

Further, plants have evolved anti-nutritional factors to protect their proteins from animal predation. To overcome these, humans apply external treatments such as fractionation, soaking, heating, acidification, fermentation and pulverisation. Treatment takes time and energy, and causes losses, which increases the greenhouse gas emissions associated with the food. Soybeans, for instance, which are considered the best large-scale plant-protein source, have high concentrations of dietary trypsin inhibitors, oestrogen mimics and tannins. The result is that only about 73% of the soybean protein is digestible compared with 80–100% from animal protein.

Although plants-only agriculture has been modelled for the US to produce 23% more food, it met fewer of the US population’s requirements for essential nutrients. When nutritional adequacy was evaluated by using least-cost diets produced from foods available, more nutrient deficiencies, a greater excess of energy, and a need to consume a greater amount of food solids to meet nutritional requirements (calories) were encountered in plant-only diets (15).

Animal-derived foods meet essential amino acid needs up to 240% more effectively than plant-derived foods (16). This means that vegans excrete far more excess N (as much as 140%) than carnivores, all of which is at some point oxidised to nitrous oxide, a GHG, in the atmosphere. Vegans also require more land and calories to meet their EAA needs, and supplements (which are not included in environmental impact of diet calculations). A modelling study on ‘people fed’ from the Canterbury Plains (17) concluded that mixed dairy/cropping systems provided the greatest quantity of high-quality protein per unit price to the consumer, had the highest food energy production and supported the dietary requirements of the highest number of people, when assessed as all-year-round production systems.

Miscalculation, misrepresentation and misunderstanding

The claims that plant-based diets are environmentally better than omnivorous diets have been challenged and some have been discredited.

The FAO 2006 document ‘Livestock’s Long Shadow’ (18) has had global impact. The document stated that livestock agriculture produced 18% of global emissions, and that “Livestock was doing more to harm the climate than all modes of transportation combined”. The analysis used a complete life-cycle for meat (emissions from fertiliser production, converting land from forests to pastures, growing feed, and direct emissions from animals [eructation and manure] from birth to death) and compared the result with an incomplete assessment of transport – the emissions were calculated on exhaust from vehicles only.

More recent research from the FAO (19) showed that grazing livestock contribute directly to global food security by producing a greater amount of highly valuable nutrients for humans, such as high-quality proteins, than they consume. Research (20) indicates that somewhere between 7 and 13% of beef production comes from feed lot systems, yet most of the concerns about GHG are based on this small percentage.

Of further interest, the authors state that “out of the 2.5 billion ha needed for animal production, 77% are grasslands, with a large share of pastures that could not be converted to croplands and could therefore be used only for grazing animals”. Note that these grasslands in New Zealand support considerable soil carbon stocks and biodiversity – not as much of the latter as native forests, but certainly more of both than arable areas where soil disturbance is part of production.

Greenpeace International suggested in 2018 that diets should be reconsidered for both human health and the environment. Reductions in meat and dairy consumption were recommended, not a complete removal of animal products from the diet. The take-home message was that land that could be used for growing food for direct human consumption should be, with animal products coming from land that was not suitable for anything but pasture (21).

Furthermore, the 2019 IPCC 24 (22) reports did not advocate becoming vegan. It stated that “balanced diets, featuring plantbased foods, such as those based on coarse grains, sustainable legumes, fruits and vegetables, nuts and seeds, and animal-sourced food in resilient, sustainable and low GHG emission systems, present major opportunities for adaptation and mitigation while generating significant co-benefits in terms of human health”.

Despite the available research, position papers such as the ‘Save the Planet’ diet proposed by the EAT-Lancet Commission (23) have continued to be promoted. They fail to recognise population health realities. Plant-based diets require consumers to eat a significantly greater amount of dietary energy than is good for health (15) to obtain enough of all other nutrients. Only an animal-based diet can solve this problem.

The future

Nutrition company Cargill’s March 2019 survey ‘Feed4Thought’ (24) found that more than two thirds of people surveyed in four countries intended to maintain or increase their consumption of animal protein this year.

Although 80% were interested in exploring plant-based or alternative sources of protein, they were not intending to drop the animal component of their diets. In addition, 93% of them considered animal protein was an important part of a healthy (and delicious) diet, and 80% of them believed that animal protein could be part of an environmentally friendly diet. The facts allow them to do so with a clear conscience and the dietary data (6) indicate that omnivores are prevalent. Further, recent reports suggesting that the “appetite for plant-based meat has already peaked” (25) indicate that consumers have been seeking variety by incorporating new products into their diets, rather than as a lifestyle switch.

New Zealand pastoral farming produces animal protein (meat and milk) for fewer GHG emissions per unit of protein than other countries currently manage (26, 27). The Paris Climate Agreement emphasised decreasing GHG without compromising food production. Poorer performance in other countries affects us through, for instance, temperature and sea level rises. New Zealand is part of the physical, chemical and biological globe and cannot isolate itself through policy.

Calculating land use and environmental impacts based on essential amino acids would create a different picture for New Zealand (17). A full life-cycle analysis of proposed alternative food production systems would create a different outcome from that espoused. Adaptive strategies are in good farmers’ DNA. So is identifying bullshit – sorting the claims from the reality.

SOURCE CODE

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