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Are 'clean eating' diets really better for our health and the environment?

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Thinking of switching to almond milk for the sake of the planet? Maybe think again. 

We share the planet with about 23 billion chickens, turkeys, geese, ducks and guinea fowl – three for every human being. And farming these creatures – not to mention all the cows, sheep, pigs and goats – is threatening the Earth. Our appetite for eating animals and their milk products is contributing to deforestation, the extinction of species, pollution and climate change. Never before has what we put on our plates been so fraught.

Little wonder that the number of vegans in the UK has risen by 350% in the past decade, notably among younger people. Yet the imperative to go animal-free is complicated by misinformation: Netflix’s What the Health advanced incendiary claims about the damage animal products are doing to us, but its assertion, for instance, that eating an egg a day is equivalent to smoking five cigarettes turned out to be short on evidence.

The growing absolutism about food and the potentially damaging mania for so-called “clean eating” moved food historian Bee Wilson to speak out: humans are omnivores, she points out; we are used to eating plants, but also a little meat.

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The healthy trap

Meat and dairy are far from being the whole cause of the problem. According to 2015 research from Carnegie Mellon University, eating fewer calories reduces energy use, water use and greenhouse gas emissions from the food supply chain. However, eating the recommended “healthier” foods – a mix of fruit, vegetables, dairy and seafood – increased the environmental impact in all three categories: energy use went up by 38%, water use by 10% and CO2 emissions by 6%.

Lettuce, the study found, is three times worse in terms of greenhouse gas emissions per calorie than bacon, because the transport cost per calorie is higher. And because it perishes more quickly, the proportion that goes to waste further increases its emissions footprint.

Certainly, leafy greens are good for you, but not all salad leaves are equally nutrient-dense: the pallid but popular iceberg lettuce is lower in vitamins A, K and C, folic acid and antioxidants than darker greens such as spinach and kale or red varieties such as lollo rosso. And the longer any leafy veg spends languishing in the crisper drawer of the fridge, the more the vitamin content declines.

That’s not a reason to skip the salads this summer – especially if you’re trying to lose weight. Researchers at Penn State University found that eating a large salad before a main course reduced total calorie intake by 12%.

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Dig it

For the good of the environment, your health and your tastebuds, the best option is to grow your own. Ecologist and blogger Tim Martin dug up his lawn and turned his small backyard in Auckland’s Mt Wellington into a productive food garden over a decade ago.

He’s worked out that a couple of hours’ toil a week saves him around $1300 a year. And his family get to eat fresh vegetables grown in soil he’s enriched with lots of organic matter. His cost-benefit analysis showed that in terms of effort, cost and input, salad greens were “a winner”.

Martin advises direct-sowing mesclun seed in blocks rather than rows (it takes less space and crowds out weeds) and growing varieties such as miner’s lettuce, tatsoi and corn salad in the winter months. Pumpkins and potatoes are also easy to grow but require more space.

His plant-and-forget pick of the tomatoes is a heritage variety called green sausage, which has proved to be resilient to pests and diseases. And broccoli is a crop that’s worth growing for health benefits: as soon as it’s picked, the nutritional quality starts declining and by the time shop-bought broccoli gets eaten it might have lost around 80% of its cancer-fighting glucosinolates.

Homegrown food also eliminates food miles and cuts down packaging, and you produce far more varieties of veg than you’ll find in the supermarket, so the family foodies will be happy too.

The beef with meat

It’s long been known that a diet high in red meat and low in plant food is associated with an increased risk of colorectal cancer – the second-highest cause of cancer deaths in New Zealand. Japan once had one of the lowest rates of this disease, but a huge increase in meat consumption has coincided with a big jump in the incidence of colorectal cancer. The World Health Organisation (WHO) estimates that the risk could increase by 17% for every 100g portion of red meat eaten daily.

However, the smart eater won’t cut out meat entirely, but just have less of it. Lean red meat in particular is a valuable source of haem iron, which is much more easily absorbed than the iron found in vegetables and pulses such as beans, chickpeas and lentils. Demand in the UK for puy lentils reportedly soared after four-year-old Prince George was served them for his school lunch, but although they can be prepared tastily and are a good source of non-haem iron, you would have to eat a lot of them to meet daily iron needs.

Iron deficiency is a common problem particularly for women who are still menstruating: it can cause fatigue and lower immunity. You can boost the iron benefit of any animal protein you do eat by avoiding combining it with foods that interfere with absorption – calcium-rich dairy with the same meal or tea or coffee within 30 minutes.

Without a doubt, we should eat less animal protein for the planet’s sake. In a new report, called Appetite for Destruction, conservation charity the World Wildlife Fund (WWF) says that if we all ate to meet our nutrional requirements rather than our appetites, the total agricultural land required would decline by 13% and 650 million hectares could be retired from agricultural production. UK figures suggest we’d be consuming 44-55g of protein a day as opposed to the current 64-88g, of which a third is meat or meat products.

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But a carnivorous environmentalist can eat a small amount of meat with a reasonably good conscience. In 2012, researchers at the University of Aberdeen examined how to improve food choices in a way that would reduce greenhouse gas emissions while still meeting the basic requirements for health. They came up with a diet that reduced emissions by 36% and was based on 52 foods including 372g of meat a week. (The same team also came up with a way to reduce emissions by 90% but that involved restricting the diet to seven foods and chewing through large amounts of fortified breakfast cereal without milk).

The other question is whether grass-fed or grain-fed animals are better for us. Some studies have shown that grass-fed red meat contains more omega-3 fatty acids, beta-carotenes and vitamin E and has less impact on cholesterol levels than grain-fed.

Intensive, grain-fed animal farming tends to produce less-nutritious food than pastoral farming – one study shows six chickens raised that way today have the same amount of omega 3 found in just one in the 1970s.

If you are planning to go vegan, you need to be aware of the risk of dietary deficiency. Tofu, cooked beans and lentils and iron-fortified breakfast cereal are good sources of non-haem iron and combining them with plenty of vitamin C-rich foods such as capsicum, kiwifruit and citrus will make it easier to absorb, but to maintain healthy iron levels you may need to take a supplement.

Vegans also risk missing out on some of the essential amino acids found in meat, so have to be careful to eat a wide variety of different foods each day. And since plant-only diets are deficient in vitamin B12, vegans should take supplements or eat fortified foods.

Fishy business

Many of us aren’t getting enough healthy omega-3 fatty acids in our diet. Recent research from Massey University shows that only a third of pregnant women are consuming the recommended 200mg a day. Fatty fish, such as tuna, salmon and sardines, are a rich source of these heart-healthy, anti-inflammatory nutrients.

Fortunately, farmed freshwater salmon rates as a good choice on Forest & Bird’s 2017 Best Fish Guide, which ranks the sustainability of seafood (downloadable as an app). Sea-farmed salmon is considered an okay option, and farmed paua, mussels and Pacific oysters can all stay on the menu, but much of the wild-caught fish that we tend to enjoy – snapper and tarakihi, for instance – are ranked by Forest & Bird as “don’t eat”. The downside of the guide is that you sometimes need to know where and how a fish was caught before you can assess its environmental acceptability, and that information is not usually available at the supermarket counter or when ordering in a restaurant.

Go for farmed seafood and you can do so in the knowledge there are strict environmental controls around aquaculture in this country’s waters. The Global Salmon Initiative found the New Zealand king salmon industry has low levels of antibiotic use, fish escapes and sea lice. However, monitoring has uncovered pollution of the seabed beneath pens at some Marlborough Sounds fish farms. And farmed king salmon are meat eaters – they’re fed on a pellet consisting of abattoir by-products, including offcuts from poultry processing. Fish oil is also added in order to boost omega-3 levels.

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Dairy-free milk

Thinking of switching to almond milk for the sake of the planet? Growing one almond requires about five litres of water and a large proportion of the world’s crop is produced in drought-stricken California. Hundreds of thousands of hectares there are planted with almond trees requiring irrigation and creating a monoculture that has been blamed for bee deaths and colony collapse.

Soy isn’t necessarily much better. The bulk of soy is grown for uses other than milk, such as animal feed, and the crop requires vast expanses of land. Soybean crops have contributed to deforestation and the loss of valuable ecosystems, having a devastating effect on species in vulnerable areas such as the Amazon. So although the average European consumes an estimated 61kg of soy each year, most of that is indirectly via animal proteins rather than from tofu or soy milk.

The downside of store-bought, plant-based milks is they are highly processed, some are sweetened and nutritional benefits vary. Almond is lower in protein than dairy; soy has much less calcium (you can buy calcium-fortified soy milk but it isn’t quite as well absorbed); rice milk has more calcium but is lower in protein and higher in carbohydrate.

The environmental impact of dairy farming in this country is quite properly under scrutiny, but cows’ milk products do provide good-value nourishment – a useful package of protein, vitamins A, B12 and riboflavin, and important minerals such as calcium, iodine, phosphorus and zinc. Adults should aim for two servings daily; children and older adults should try for three.

Eat up

So you’ve reduced your animal proteins, switched to sustainable seafood and started eating locally and seasonally. But if you’re throwing out food rather than consuming it, you’re wasting the resources that went into its production and sending it to a landfill where it will release methane as it decomposes without oxygen.

A third of food produced for human consumption is lost or wasted, according to the UN. That accounts for 4.4 gigatonnes of greenhouse gas emissions – so if food waste were a country, it would be the third-largest producer of carbon emissions behind China and the US.

In New Zealand, we throw away 122,547 tonnes of food a year. The most wasted item is bread, but we’re also chucking away leftovers, potatoes, apples, poultry, bananas and lettuce. And larger households, such as families and big flats, tend to waste most food.

The website lovefoodhatewaste.co.nz is filled with tips for storing food (keep your onions away from your potatoes or they’ll cause each other to sprout) and for using leftovers and recipes that incorporate stuff we tend to bin – even a banana-peel dhal for the more adventurous palate.

Since the Love Food Hate Waste campaign began in 2015, there’s been a decrease in waste and a reported increase in community fridges and food banks, where businesses and the public can donate edible food that would otherwise go to waste, helping feed the hungry in the process.

This article was first published in the October 21, 2017 issue of the New Zealand Listener.