The future of meat Meat consumption is rising annually as human populations grow and affluence increases. Godfray et al. review this trend, which has major negative consequences for land and water use and environmental change. Although meat is a concentrated source of nutrients for low-income families, it also enhances the risks of chronic ill health, such as from colorectal cancer and cardiovascular disease. Changing meat consumption habits is a challenge that requires identifying the complex social factors associated with meat eating and developing policies for effective interventions. Science, this issue p. eaam5324 BACKGROUND The global average per capita consumption of meat and the total amount of meat consumed are rising (see the figure), driven by increasing average individual incomes and by population growth. Growth rates vary across different regions, with consumption in high-income countries static or declining and in middle-income countries moderately to strongly increasing, whereas in low-income countries, meat consumption is on average low and stable. There has been a particularly marked increase in the global consumption of chicken and pork. The consumption of different types of meat and meat products has substantial effects on people’s health, and livestock production can have major negative effects on the environment. ADVANCES Meat is a good source of energy and some essential nutrients—including protein and micronutrients such as iron, zinc, and vitamin B12—although it is possible to obtain a sufficient intake of these nutrients without eating meat if a wide variety of other foods is available and consumed. In high-income Western countries, large prospective studies and meta-analyses generally show that total mortality rates are modestly higher in participants who have high intakes of red and processed meat. The strongest evidence of a specific adverse effect is the increased risk of colorectal cancer with high intakes of processed meat. Meat produces more emissions per unit of energy compared with that of plant-based foods because energy is lost at each trophic level. Within types of meat, ruminant production usually leads to more emissions than that of nonruminant mammals, and poultry production usually leads to less emissions than that of mammals. Meat production is the single most important source of methane, which has a relatively high warming potential but a low half-life in the environment compared with that of CO2. Careful management of grassland systems can contribute to carbon storage, but the net benefits are likely to be relatively modest. Agriculture uses more freshwater than any other human activity, with nearly a third required for livestock, so meat production in water-stressed areas is a major competitor with other uses of water, including that required to maintain natural ecosystems. Meat production can be an important source of nitrogen, phosphorus, and other pollutants and affects biodiversity—in particular, through land conversion to pasture and arable feed crops. OUTLOOK Governments act to shape food systems for economic purposes and to protect health from contaminated food. But there is less agreement over the degree to which the state should use health, environmental, or animal welfare considerations to control the supply of meat through interventions that affect the production, sale, processing, and distribution of meat and meat products or the price to the consumer. If we are to shape consumer demand, more evidence is needed about the effectiveness of different interventions to influence food selection. This may include interventions that affect either the conscious, reflective decision-making systems or nonconscious, automatic processes. Potential interventions within the rational choice paradigm include labeling schemes (based on health or environmental criteria) and certification programs (based on welfare or environmental considerations) or fiscal interventions (such as so-called fat taxes). Alternatively, the largely automatic responses to environmental cues that affect purchase and consumption behaviors can be manipulated by changes to the food environment, in retail and food consumption settings. History suggests that change in dietary behaviors in response to interventions is slow. But social norms can and do change, and this process can be aided by the coordinated efforts of civil society, health organizations, and government. However, successful interventions to improve health and environmental objectives are likely to require a good understanding of the impact of meat consumption on these outcomes, as well as a license from society for governments and other bodies to implement a suite of interventions to stimulate change. Total consumption of meat (in million metric tons) in different regions and (inset) globally. [Data are from www.fao.org/faostat/en/?#data.] Both the global average per capita consumption of meat and the total amount of meat consumed are rising, driven by increasing average individual incomes and by population growth. The consumption of different types of meat and meat products has substantial effects on people’s health, and livestock production can have major negative effects on the environment. Here, we explore the evidence base for these assertions and the options policy-makers have should they wish to intervene to affect population meat consumption. We highlight where more research is required and the great importance of integrating insights from the natural and social sciences.

中文翻译：

---

肉类消费、健康和环境

肉类的未来随着人口的增长和富裕程度的增加，肉类消费量每年都在增加。戈弗雷等人。回顾这一趋势，这对土地和水资源的利用以及环境变化产生了重大的负面影响。尽管肉类是低收入家庭的主要营养来源，但它也增加了患慢性疾病的风险，例如结直肠癌和心血管疾病。改变肉类消费习惯是一项挑战，需要确定与肉类食用相关的复杂社会因素并制定有效干预政策。科学，本期第 3 页。eaam5324 背景 在个人平均收入增加和人口增长的推动下，全球人均肉类消费量和肉类消费总量正在上升（见图）。不同地区的增长率不同，高收入国家的消费量保持不变或下降，中等收入国家的消费量适度至强劲增长，而低收入国家的肉类消费量平均较低且稳定。全球鸡肉和猪肉的消费量出现了特别显着的增长。不同种类的肉类和肉制品的消费对人们的健康产生了重大影响，而畜牧生产可能对环境产生重大负面影响。进步 肉类是一种很好的能量来源和一些必需营养素——包括蛋白质和微量营养素，如铁、锌和维生素 B12——尽管如果有多种其他食物，则可以在不吃肉的情况下获得足够的这些营养素摄入量。可用和消耗。在高收入的西方国家，大型前瞻性研究和荟萃分析通常表明，摄入大量红肉和加工肉类的参与者的总死亡率略高。特定不利影响的最有力证据是大量摄入加工肉类会增加患结直肠癌的风险。与植物性食物相比，肉类每单位能量产生的排放量更多，因为能量在每个营养级都会损失。在肉类种类中，反刍动物生产通常比非反刍哺乳动物排放更多，家禽生产通常比哺乳动物排放更少。肉类生产是甲烷最重要的单一来源，与二氧化碳相比，甲烷具有相对较高的升温潜能，但在环境中的半衰期较短。对草地系统的谨慎管理有助于碳储存，但净收益可能相对较小。农业使用的淡水比任何其他人类活动都要多，牲畜需要近三分之一的淡水，因此缺水地区的肉类生产是其他用水（包括维持自然生态系统所需的用水）的主要竞争对手。肉类生产可能是氮、磷和其他污染物的重要来源，并影响生物多样性——特别是通过将土地转化为牧场和可耕种饲料作物。展望 政府为经济目的塑造食品系统并保护健康免受食品污染。但是对于国家应该在多大程度上使用健康、环境、或动物福利考虑，通过影响肉类和肉类产品的生产、销售、加工和分销或消费者价格的干预措施来控制肉类供应。如果我们要塑造消费者的需求，就需要更多的证据来证明不同干预措施影响食物选择的有效性。这可能包括影响有意识、反思性决策系统或无意识、自动过程的干预措施。理性选择范式中的潜在干预措施包括标签计划（基于健康或环境标准）和认证计划（基于福利或环境考虑）或财政干预措施（例如所谓的脂肪税）。或者，对影响购买和消费行为的环境线索的基本自动反应可以通过改变食品环境、零售和食品消费环境来操纵。历史表明，饮食行为因干预而发生的变化是缓慢的。但是社会规范可以而且确实会发生变化，而这一过程可以得到民间社会、卫生组织和政府的协调努力的帮助。然而，改善健康和环境目标的成功干预措施可能需要充分了解肉类消费对这些结果的影响，以及政府和其他机构实施一系列干预措施以刺激变革的社会许可。不同地区和全球（插图）的肉类总消费量（以百万吨计）。[数据来自www.fao。org/faostat/en/?#data.] 在个人平均收入增加和人口增长的推动下，全球人均肉类消费量和肉类消费总量都在上升。不同种类的肉类和肉制品的消费对人们的健康产生了重大影响，而畜牧生产可能对环境产生重大负面影响。在这里，我们探讨了这些断言的证据基础，以及政策制定者如果希望干预以影响人口肉类消费的选择。我们强调需要更多研究的地方以及整合来自自然科学和社会科学的见解的重要性。受个人平均收入增加和人口增长的推动。不同种类的肉类和肉制品的消费对人们的健康产生了重大影响，而畜牧生产可能对环境产生重大负面影响。在这里，我们探讨了这些断言的证据基础，以及政策制定者如果希望干预以影响人口肉类消费的选择。我们强调需要更多研究的地方以及整合来自自然科学和社会科学的见解的重要性。受个人平均收入增加和人口增长的推动。不同种类的肉类和肉制品的消费对人们的健康产生了重大影响，而畜牧生产可能对环境产生重大负面影响。在这里，我们探讨了这些断言的证据基础，以及政策制定者如果希望干预以影响人口肉类消费的选择。我们强调需要更多研究的地方以及整合来自自然科学和社会科学的见解的重要性。我们探讨了这些断言的证据基础，以及政策制定者如果希望干预以影响人口肉类消费的选择。我们强调需要更多研究的地方以及整合来自自然科学和社会科学的见解的重要性。我们探讨了这些断言的证据基础，以及政策制定者如果希望干预以影响人口肉类消费的选择。我们强调需要更多研究的地方以及整合来自自然科学和社会科学的见解的重要性。