The impact of meat consumption on the tropics: reply to Machovina and Feeley William F. Laurance 1 , Jeffrey Sayer 1 , and Kenneth G. Cassman 2 1 Centre for Tropical Environmental and Sustainability Science and College of Marine and Environmental Sciences, James Cook University, Cairns, QLD 4878, Australia 2 Department of Agronomy and Horticulture, University of Nebraska, Lincoln, NE 68583, USA Machovina and Feeley [1] are correct that increasing meat consumption is having a major impact on the tropics, both via habitat conversion for grazing and expanding feed-crop production. We did underscore this issue in our TREE review [2] and elsewhere [3]. However, we believe that reducing global meat consumption, although a laudable goal, will be more challenging than Machovina and Feeley suggest. Increasing meat consumption in developing nations is a powerful trend that parallels similar trends that have oc- curred previously in industrial nations, almost all of which have a per-capita meat consumption exceeding 40 g per day. Most food-security experts have little doubt that meat con- sumption will increase with improving living standards, given long-standing human preferences for meat. For in- stance, Chris Barrett, an agricultural economist at Cornell University, has labeled efforts to limit meat consumption as ‘aspirations not components of a viable food security strategy’ (https://www.soils.org/files/am/ecosystems/cassman.pdf). Strong preferences for meat arise in part because it confers important health benefits for those who lack the luxury of unlimited calories. At low caloric intakes, meat is often an important protein source, with three times as much protein per calorie as vegetal products and an amino acid composition closer to human requirements [4]. Meat also has a higher uptake efficiency than vegetal matter and is rich in micronutrients, such as B-group vitamins and minerals, which are important for childhood growth and pregnant and lactating women [4]. Largely for such reasons, nations with a low per-capita intake of animal protein have a high incidence of child undernourishment (http://www.fao.org/publications/sofi/en/). Hence, it is ac- ceptable to emphasize the need to reduce meat consump- tion in wealthier nations, where overly meat-rich diets can be damaging to health, but unrealistic to expect those in developing nations not to increase meat consumption as their living standards improve. There are also good reasons why livestock production is so widespread in the developing world. For small-scale farm- ers, ruminant livestock are a flexible resource that converts low-quality protein (grass) into high-quality protein (meat and milk). This is particularly important for farmers living in marginal lands unsuitable for agricultural crops. For the economically disadvantaged, livestock also provide a vital insurance policy [5]: they can be consumed during lean times or sold for cash to pay for schooling or a medical emergency, for instance. For such reasons, livestock are seen as a status symbol in many developing countries, emblematic of good fortune and social standing. Thus, although there is no doubt that livestock produc- tion is promoting habitat destruction in the tropics, we believe that efforts to reduce meat consumption need to be realistic and integrated with human-development goals [6,7]. The greatest benefits, we believe, will be achieved by emphasizing the considerable health advantages of modest animal-protein diets [8] to those in industrial nations and to the growing middle and upper classes of developing nations, for whom food-security issues and adequate calorie intakes are not pressing daily concerns. Coupled with this, ecological-intensification strategies [9] that strive to increase livestock yields on current grazing lands and reduce the expansion of new grazing lands [10], plus eco-certification of meat and feed-crops to discourage further habitat conversion [11,12], could help to limit the impacts of livestock production. References 1 Machovina, B. and Feeley, K.J. (2014) Meat consumption as a key impact on tropical nature: a response to Laurance et al.. Trends Ecol. Evol. 29, 430–431 2 Laurance, W.F. et al. (2014) Agricultural expansion and its impacts on tropical nature. Trends Ecol. Evol. 29, 107–116 3 McAlpine, C.A. et al. (2009) Can the global environment sustain the increasing world consumption of beef? A call for policy action based on evidence from Queensland (Australia), Colombia and Brazil. Global Environ. Change 19, 21–23 4 Gibney, M.J. et al., eds (2009) Introduction to Human Nutrition (2nd edn), Wiley-Blackwell 5 Seigmund-Schultze, M. et al. (2007) Cattle are cash generating assets for mixed smallholder farms in the Eastern Amazon. Agric. Syst. 94, 738–749 6 UNDP (2013) Annual Report: Supporting Global Progress, United Nations Development Program 7 Ehrlich, P.R. et al. (1997) The Stork and the Plow: The Equity Answer to the Human Dilemma, Yale University Press 8 Levine, M.E. et al. (2014) Low protein intake is associated with a major reduction in IGF-1, cancer, and overall mortality in the 65 and younger but not older population. Cell Metab. 19, 407–417 9 Cassman, K.G. (1999) Ecological intensification of cereal production systems: yield potential, soil quality, and precision agriculture. Proc. Natl. Acad. Sci. U.S.A. 96, 5952–5959 10 Ermgassen, E. et al. (2014) Livestock: tackle demand and yields. Nature 508, 186 11 VanWey, L.K. and Richards, P.D. (2014) Eco-certification and greening the Brazilian soy and corn supply chains. Environ. Res. Lett. 9, 031002 12 Alves-Pinto, H.N. et al. (2013) Certifying Sustainability: Opportunities and Challenges for the Cattle Supply Chain in Brazil, CGIAR Research Program on Climate Change, Agriculture and Food Security 0169-5347/ ß 2014 Elsevier Ltd. All rights reserved. http://dx.doi.org/10.1016/j.tree.2014.05.010 Corresponding author: Laurance, W.F. (bill.laurance@jcu.edu.au). Letters Trends in Ecology & Evolution August 2014, Vol. 29, No. 8 432