Deforestation. Child labour. Pollution. Water shortages. The more we learn about the side-effects of food production, the more the act of feeding ourselves becomes fraught with anxiety. How can we be sure that certain foods are “good” or “bad” for society and the planet? As Tim Lang, professor of food policy at City University of London and the co-author of Sustainable Diets, puts it: “When you come to ‘judge’ food, you end up with an enormous list of variables, from taste to health outcomes to biodiversity.” Here are some of today’s most controversial products – and some thoughts that may help you when shopping.

Avocados



Let’s start with an easy one ... No, sorry: this brunch staple is deeply problematic. The global hunger for avocados indirectly fuels deforestation, while in Chile, from where many UK supermarkets get their supplies, it has reduced drought-stricken farmers to diverting water from emptying rivers. It is hard to make the case for avos when the nutritional benefits (vitamins E and K, monounsaturated oils) are readily available in products closer to home, says the investigative journalist Joanna Blythman. But if the thought of life without guac grieves you, be prepared to fork out for Fairtrade avocados, such as those from the Mexican growers collective Pragor.

Bagged salad



“It’s in plastic, it’s the most thrown-away food item, at this time of year it’s grown under LED lights in the Netherlands – it’s pointless,” is Lang’s damning verdict. About 40% of the bagged salad we buy every year in Britain is thrown out – because it is often bought without a meal in mind, and because use-by dates are so conservative. Tesco introduced resealable bags for salad in 2017, but even then, there’s the plastic and the carbon footprint of transportation to contend with, not to mention the ensuing deterioration of flavour. Come summer, buy whole, British-grown lettuce; meanwhile, consider cabbage or winter greens.

Beef



Leaving aside the slaughter of sentient beings for human consumption (if you can), arguments against beef revolve around greenhouse gases. According to the Food and Agriculture Organization of the United Nations (FAO), cattle (raised for both beef and milk) are the animal species responsible for the most emissions; yet this dismal statistic hides a wide variation in production practices and thus emission intensity, as the FAO acknowledges.

“There’s a big difference between the way beef is produced here than in the US,” Blythman says. “There is no convincing evidence that rearing cattle in regenerative, pasture-based systems is bad for the environment; on the contrary, these permanent pastures act as carbon sinks.” To dig them up would “release the carbon locked into the soil”.

The UK is not free of intensive farms, but, “generally, our standard of beef production is high”. Buy organic and grass-reared, buy infrequently and, if you’re eating out look for beef from retired dairy cows. “I love the flavour and, more to the point, the concept of respecting the animal at the end of its working life,” says the chef and sustainability pioneer Adam Handling.

Isn’t it good ... Norwegian cod. Photograph: Alamy Stock Photo

Cod



The royal spouse of the seas, no sooner is cod in favour than it is back out again. According to the Marine Conservation Society (MCS), populations in UK waters are in dire straits. The status of Norwegian cod, however, is quite different: Norway was the first country in the world to introduce a quota system for its cod, and its fishing culture is built around the quality, sustainability and safety of this historic resource. “It’s not always the most ethical choice to use produce from close to home, and cod is a good example of this,” says Handling. “I only buy cod from Norway, where I know that maintaining the stock is encouraged and supported.”

Milk



“Milk is rich in nutrients,” says Blythman, and cheaper than alternatives such as oat or almond milk. “We are a wet country, where grass grows everywhere – even in places unsuitable for arable crops.” How better to utilise this land than to convert that grass into nutrient-dense food? But this argument only holds if you are talking about milk from cows on a grass-based diet, as opposed to those intensively farmed on grains. So you will have to pay for high-welfare, free-range milk in every cuppa. And there is no getting away from the fact that cattle still die as part of milk production, from unwanted male calves to “retired” dairy cows.

Nut butters and palm oil



“Not this as well,” I hear you cry, a spoonful of almond butter halfway to your mouth. Well, it’s complicated. The first thing to ask of your nut butter is: is it palm oil-free? Palm is one of the biggest drivers of global deforestation, and while there are sustainable sources, neither Lang nor Blythman is convinced. “It’s not clear to what extent certified sustainable palm oil reduces deforestation,” says Lang.

That’s before you get to the nuts, which could be causing water shortages (Californian almonds), child labour (Turkish hazelnuts) or human rights abuses (Vietnamese cashew nuts). As ever, governments in these countries claim ‘“systems are being put in place” – but the scale and distance of these industries makes traceability very difficult. Buying nuts closer to home isn’t necessarily lower-carbon, but at least you have a better idea of what has been going on. Buy in bulk from suppliers such as Food & Forest, which supports mixed farming systems in Spain, Italy and the UK, and make your own, or stick to classic (palm oil-free) peanut butter. Peanuts are naturally a sustainable crop that demands little water, has nitrogen-fixing properties and, when planted in rotation with other crops, reduces soil erosion.

Soya



The proportion of soya consumed directly by humans is relatively small, so it is misleading to put deforestation at the door of tofu and soya milk. If you are vegan, “bad” soya is easy enough to avoid: tofu made from US and European soya is increasingly available, and most of the soya used by Alpro is European. Problems arise when it comes to meat, fish and dairy, says Lang – which is where the vast majority of the world’s soya is used. “It is almost impossible to know whether what you are buying has been fed soya” – and whether it has come from Brazil and Argentina, where soya-farming fuels deforestation. Buy organic, local and as directly from the farm or fishery as you can.

Chocolate



With most big-brand bars containing soya and palm oil, chocolate carries ethical baggage before you even consider the cocoa. Factor in that most cocoa comes from smallholders in Côte d’Ivoire and Ghana, who bear the burden of price fluctuations, and you are looking at entrenched poverty and all the consequences. The 2018 Cocoa Barometer, produced by a consortium of not-for-profits, reported that, on average, Côte d’Ivoire cocoa farm households earn only 37% of a living income. As a result, “not a single company … is even near their commitments of a 70% reduction of child labour by 2020”, let alone the complete elimination they are supposedly working towards. Then there is deforestation: more than 90% of West Africa’s original forests are gone thanks partly to the demand for cheap cocoa. With the Rainforest Alliance concentrating on environmental protections and Fairtrade focusing on living and working standards, it is hard to find a bar that delivers on both issues. “Fairtrade is still not delivering enough money to primary producers,” says Lang, citing an academic study that reported that Fairtrade-certified cocoa farmers in Ghana earned only $36 in a growing season more than non-certified ones.

Octopus



Although ethical waters are rarely clear, they are particularly murky when it comes to octopus. On the one hand, octopuses are highly intelligent and there is compelling evidence to suggest they experience pain-like feelings. On the other, says Jon Ablett, senior curator of mollusca at the Natural History Museum, cephalopods are “quite a sustainable group [of sea creatures] to eat. They only live for one to two years, and we tend to catch adults that have already reproduced. You just need to avoid those caught through deep sea trawling.” Although octopuses can be overfished, they reproduce quickly. “One interesting commonality between humans and octopus is that they find new ways to live as their environment changes,” says the marine biologist Danna Saaf. As cephalopods fill the gap left by their overfished predators, so humans may come to depend on them for survival.

Prawns



There is a new “seafood imperialism” abroad, and our appetite for large prawns is in part to blame, says Lang. Large – tiger and king – prawns are farmed in warm waters in countries such as Thailand, Sri Lanka and Madagascar, where production is often “heavily involved in the destruction of mangrove swamps”. Takeaway prawns are particularly perilous, says the MCS, because they are generally giant river prawns, the production of which is seriously depleting wild stock. Choose small cold-water prawns – best choice, says the MCS – or prawns from the Happy Prawn Co, an ethical company that produces 100% natural and traceable black tiger prawns from Indonesia.