Update: Grant Schofield has since replied to this post, which we have addressed in a second article, entitled: Grant Schofield, LCHF, & Climate Misinformation.

Planetary Health

Grant Schofield, a Professor of Public Health and the Director of the Human Potential Centre at AUT, was recently appointed Chief Education Health and Nutrition Advisor to NZ’s Ministry of Education. As a proponent of the Low Carb, High Fat (LCHF) movement, Grant Schofield and his small team based at AUT’s Human Potential Centre are frequently littering their social media pages with information that runs contrary to the general scientific consensus regarding healthy nutrition.

It is no wonder then, that his government appointment has been met with some controversy. Helen Gibbs has submitted an Official Information Request to the Ministry of Education asking for details concerning Grant Schofield’s appointment (see below). The only response she has received thus far has been a short letter informing her that the time frame for response needed to be extended on the grounds that the ‘consultations necessary to make a decision on the request are such that a proper response…cannot reasonably be made within the original time limit.’ Let us hope that the Ministry, in their response to Helen Gibbs, which they are legally obligated to provide by June 14th, are able to clearly outline how they performed all of the necessary consultations when they chose to appoint Grant Schofield in the first place. You can follow these developments here.

Jim Mann, Lisa Te Morenga, Rod Jackson, Boyd Swinburn, and others, some of New Zealand’s leading public health and nutrition experts, must also be disappointed with the decision, given that they have recently been engaged in a fat debate with Grant Schofield and his team within the Letters of the Lancet medical journal.

A Case of New Zealand Climate Misinformation

©  2016, Plant Based Living Initiative

‍‍‍©  2016, Plant Based Living Initiative

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Environmental Misinformation

The purpose of this blog post, though, is not to engage in yet another short-sighted macronutrient-related debate; rather, it aims to clarify some specific environment-related misinformation, which has been included in a number of blog posts on Grant Schofield’s website.

Of greater concern than the misinformation itself is the fact that our efforts to participate within the comments section of his website were unsuccessful (we promise that we were polite), and messages asking him why this was the case were left unanswered.

Filtering the comments section of a blog to only allow responses that are conducive to a certain point of view is not something that we should expect from any academic, let alone a part-time public servant.

What are Schofield and Henderson comparing a vegan diet to when they say that it ‘will have a larger environmental impact if you need to eat more imported food and out-of-season (produce)?' Are they comparing it to another, even more environmentally friendly, plant-based diet, or are they comparing it to an LCHF-type diet? The latter is certainly more detrimental to the environment.

In 2010 and 2012, greenhouse gas footprint studies were performed for NZ reared lamb and beef. According to those studies, 20 kilograms and 16 kilograms of CO2 equivalents are released from the production of every 1 kilogram of raw beef and lamb, respectively [1,2]. Despite NZ’s unique geographical context, these estimates are not all that different from those in other parts of the world. In comparison, the majority of whole plant foods are associated with less than 0.5 kilograms of CO2 equivalents per kilogram of produce- that is according to the largest, most comprehensive international systematic review to date that was published in 2017 [3]. These values are consistent with studies focussing on apple, kiwifruit, and onion production within NZ [4-6]. This means that, per kilogram of product, beef is associated with ~40X more greenhouse gas emissions than the majority of plant foods. It is well-established that, overall, animal foods are substantially more water, land, and greenhouse gas intensive than plant foods. Furthermore, with regard to how these foods compare on a per gram of protein basis, beef and lamb are associated with 250X more emissions as compared to legumes [7]. On a per serving basis, there are fewer embodied emissions in 20 servings of vegetables than in a single serving of beef [7]. This information is from a 2014 publication in Nature, which also concluded that switching to a vegetarian diet, for instance, can more than halve (55%) an individual’s food-related emissions.

Regarding the claims relating to imported food and eating out of season produce, it is very well established that the contribution of food miles to the overall emissions of any given food is very low. To provide one example, shipping 1 kilogram of produce ~17,000 kilometres between the UK and NZ releases only ~0.12 kgCO2e [6]. These estimates do vary slightly (depending on the data set chosen, the type of ship used, etc), but we ought to appreciate that a value of 0.12 is 160x smaller than the 20 kgCO2e assigned to the production of every one kilogram of NZ beef. Not all modes of transport are equal, though: air-freight, for example, is known to be much more climate intensive than using ships or trucks. Very few products, however, are flown into NZ (see below table) and, while we ought to be cautious of these foods (typically exotic fruits and vegetables), it is important to note that their greenhouse gas contributions do still remain significantly lower than those of ruminants [8].

Finally, as for the impact that animal agriculture has had on our environment, the recent OECD Environmental Performance Review on NZ clarifies just how critical the situation has become.

In terms of one’s food-related environmental impact, Schofield and Henderson are right at least in one instance: 'it all depends what foods you eat.'

Citations

[1] Ledgard, S. F., Lieffering, M., McDevitt, J., Boyes, M., & Kemp, R. (2010). A greenhouse gas footprint study for exported New Zealand lamb. AgResearch, Hamilton, 26pp.

[2] Lieffering, M., Ledgard, S.F., Boyes, M. and Kemp, R. (2012). A Greenhouse Gas Footprint Study for Exported New Zealand Beef. AgReasearch, Hamilton, 31pp

[3] Clune, S., Crossin, E., & Verghese, K. (2017). Systematic review of greenhouse gas emissions for different fresh food categories. Journal of Cleaner Production, 140, 766-783.

[4] Milà i Canalsa, l., J. Cour Jansen, G. M. Burnip and S. J. Cowell (2006). "Evaluation of the environmental impacts of apple production using Life Cycle Assessment (LCA): Case study in New Zealand." Agriculture, Ecosystems & Environment 114(2–4): 226-238.

[5] Mithraratne, N., McLaren, S., & Barber, A. (2008). Carbon footprinting for the Kiwifruit supply chain—report on methodology and scoping study. Landcare research Contract Report LC0708/156, prepared for New Zealand Ministry of Agriculture and Forestry, 61.

[6] Saunders, C., A. Barber and G. Taylor (2006). Food Miles – Comparative Energy/Emissions Performance of New Zealand’s Agriculture Industry. Research Report 285. Lincoln, Agribusiness & Economics Research Unit Lincoln University.

[7] Tilman, D., & Clark, M. (2014). Global diets link environmental sustainability and human health. Nature, 515(7528), 518-522.

[8] Berners-Lee, M., Hoolohan, C., Cammack, H., & Hewitt, C. N. (2012). The relative greenhouse gas impacts of realistic dietary choices. Energy policy, 43, 184-190.

Follow our blog (& much more)

Included below are two recent paragraphs from Schofield’s blog, accompanied by a clarification of the misinformation included within them.  

In the first paragraph, Schofield and his co-author, George Henderson (an apparently un-credentialed Research Assistant at AUT’s Human Potential Centre), are discussing evidence presented within the BROAD study (recently published in Nature’s Nutrition and Diabetes peer-reviewed journal), a NZ-based randomised controlled trial studying the effect of a whole foods, plant-based dietary intervention on weight loss. Among other things, they argue that claims made regarding the environmental benefits of a plant-based diet are unsubstantiated:

Author: Jon Drew

Jon is a founding member of PBLI and a fourth-year medical student at the University of Otago, in New Zealand. He is currently completing an honour's degree focused on eating patterns that are both healthy and sustainable.

A few weeks later, Schofield and Henderson were at it again, this time criticising red meat-related epidemiology as being “the modern example of bad science which, because it panders to a vegetarian bias that runs along class lines, isn’t being properly criticised and is allowed to regularly misinform the public about nutrition.”

This was largely in response to NZ-based Public Health Professor John Potter’s recent editorial in the BMJ (British Medical Journal), which argued that we ought to reduce meat intake for the betterment of both personal and planetary health (discussed here). Schofield and Henderson claim that NZ reared red meat is, in fact, ‘not bad for the planet.’

Here is their rather confusing rebuttal:

Once again, there are no references to published research. For those interested, Zoe Harcombe is a ‘nutrition expert’ and advocate of the ‘Harcombe Diet’. She received a reasonably large amount of attention when, in a 2011 Daily Mail article, she attacked recommendations to increase fruit and vegetable consumption from five portions to eight portions per day, and described how ‘science’ suggests that they are actually ‘pretty useless nutritionally.’

A blog article posted in response by the UK division of the World Cancer Research Fund criticised the Daily Mail for publishing the article, and for giving Harcombe’s views ‘a credibility that they simply don’t deserve.’

Ben Goldacre, British physician and author of Bad Science, revealed in a Guardian column that Harcombe had admitted to him that she was not, in fact, studying for a PhD in nutrition as she had claimed she was in her article.

That is probably enough about Grant Schofield for now. If you wish to read some other articles on sustainable eating and the benefits of a plant-based eating pattern, feel free to explore the links below.

Food Imports into NZ by Mode of Transport (2016)

*A note for interpretation: the vast majority of food we consume in NZ is produced here, hence it is important to remember that these percentages relate only to the very small fraction that we do import.