In a review published in the Proceedings of the Nutrition Society, Dr Jennie Macdiarmid from the Rowett Institute of Nutrition and Health, Aberdeen, addressed the question whether a healthy diet could also be environmentally sustainable.
While she found that it might be possible to achieve, one should not automatically assume that they go hand-in-hand.
She found that 20–30% of GHGE in the UK originated from dietary intake – most commonly the “overeating” of meat and dairy.
Less environmental impact
However, from an environmental perspective, studies have shown that replacing meat in a diet does not necessarily result in less environmental impact. For instance, if meat is replaced by fruit and vegetables, while keeping the total dietary energy constant, the resulting diet would actually have higher GHGE.
While it might have health benefits, reducing meat consumption to lower levels could pose other problems. On the one hand, fish is considered healthy because it is rich in omega-3 fatty acids, but overfishing poses a serious threat to current fish stocks. Another example she highlighted was low fat products, where there is no use for the removed fat and innovative solutions are needed to reduce this food waste.
“While recent research showed that it is possible to achieve a realistic diet that meets dietary requirement for health and has lower GHGE, it cannot be assumed that a healthy diet will always have lower GHGE,” said Macdiarmid.
Dietary recommendations
She found consumer understanding of sustainable diets was often poor and a more effective combination of research and communication was needed to establish dietary recommendations which could fulfil both of these societal goals.
“There is no easy answer to the question whether a healthy diet is an environmentally sustainable diet. This review outlines the importance of food choice in influencing two main challenges: health issues and climate change,” she added.
“Due to the complexity of the term sustainability and potential conflicts when looking at a healthful diet at the same time, a joint approach is necessary. This has to include all actors from farm to fork – the agricultural sector, the food industry and the consumer.”
Clear information and communication were needed to create awareness on the effects of daily food choices – not only on obesity, but also on climate change, said Macdiarmid.