Earth Chat

A Gentleman’s Guide to Old-Fashioned (but Sustainable) Eating

What should we have for dinner? This seemingly simple question is often confusing to modern consumers in developed regions, including Hong Kong. Bombarded with a plethora of food choices, countless health and nutrition "experts" telling people what to eat and what not to eat, and a growing awareness that modern diets can lead to greater social exploitation, environmental pollution, and climate change, consumers may feel overwhelmed. So how can we eat healthily, enjoyably, and responsibly for the environment and society? In the book In Defense of Food, author Michael Pollan provides a simple seven-word answer: "Eat food. Not too much. Mostly plants.” This is in fact a very "old-fashioned" way of eating. After all, our ancestors have been eating this way for thousands of years, but it is revolutionary compared to today's highly industrialised food systems. In the following, I will explain these three principles and explore ways to rethink the important issue of "what to eat" from the perspectives of personal health and environmental sustainability.

Eat "real" food:Try to choose natural, unprocessed and additive-free food. Modern people often opt for fast food and processed food, which are often high in sugar, salt, fat and various additives. Excessive intake could lead to health problems such as obesity, diabetes, cardiovascular disease and cancer. Moreover, agriculture in itself is a major source of climate change-inducing greenhouse gases (such as carbon dioxide, methane and nitrous oxide) and environmental pollutants (such as ammonia, nitrate and other reactive nitrogen compounds), accounting for 30 to 40% of total global greenhouse gas emissions. The production, packaging and transportation of processed foods accounted for over 10% of the sector’s emission[1]. Here, Pollan has provided some interesting and practical advice: If your grandmother cannot recognize what you are eating, or if the ingredient list consists of more than five ingredients, especially if you hardly store these ingredients in your own kitchen, you should eat as little of this kind as possible. This also implies that, traditional food cultures tend to be healthier and less environmentally damaging than modern fast food cultures.

Not too much: Over-eating is one of the culprits behind the diseases mentioned above, and over-consumption often leads to food waste. About one-third of food produced each year is wasted, and discarded food produces large amount of methane[2]. Pollan recommends us to stop eating before feeling full, choose smaller portions of food, prepare only the necessary amount, and share food with others at the dining table, which allows us to enhance social bonding while reducing waste. In fact, traditional Chinese medicine also advocates eating in moderation, suggesting we eat until we are 70% full, so as not to increase the burden on the digestive system and affect our health.

Mostly plants: Over the past 60 years, the global per capita meat consumption has doubled. The preference for meat does not just bring various health risks to people; 60% of greenhouse gas emissions from agriculture are indeed associated with meat production[3]. The environmental impact of animal-based food is much higher than that of plant-based food for many reasons. For example, deforestation driven by cropland and pastureland expansion releases carbon dioxide. Fertilizers used in growing animal feed, as well as animal waste, release nitrous oxide and other reactive nitrogen pollutants. Among all animals, fish and seafood have lower carbon and nitrogen emissions, followed by poultry and pork; cattle and sheep, which are ruminant livestock, generate the highest emissions[4]. This is because, when cattle and sheep eat, microbes in their guts ferment their food and produce methane. And very often, lots of land has to be deforested for cattle ranching and growing feed. 

I do agree that meat consumption is an essential element of culture, festivity and health, as humans have been omnivores since ancient times. Therefore, like Pollan, I do not advocate "no meat", but "less meat". In fact, nutritionists recommend that adults should only consume 60 to 75 grams of meat per day (i.e., about palm size), but the average Hong Kong person eats more than 200 grams of meat per day, which is definitely an excessive intake[5]. Thus, we may start with reducing the consumption of beef and other red meat, and obtain protein from beans, eggs, milk, fish and so on, to limit the daily meat consumption to no more than 75 grams. We may also try to practice vegetarianism from one to several days a week. This will not only make our body healthier, but also reduce the damage to the Earth's resources, climate and environment.

Greenhouse gas emissions from food products (Image source: Brent F. Kim et al.)

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