Changing Diets Amid a Changing Climate

The increasing demand for animal protein has caused much concern because of its impact on the environment and contribution to climate change. Calls to reduce meat consumption and to move towards more plant-based diets have received much attention, exemplified by the release of the highly-respected EAT–Lancet Commission 2.0 report in October 2025. A global move to plant-based diets could lead to reductions in greenhouse gases by as much as two-thirds.

However, the shift towards a plant-based diet has its own set of concerns. Climate change is known to impact the quantity of food produced through reduced crop yields and crop loss. As plant-based diets become more commonplace, it becomes important to ask whether climate change also affects the quality of the plant food produced and consequently the nutritive value of vegetables and staples.

Collaborative research should be increased through existing ASEAN mechanisms to develop more climate-resilient, nutrient-rich crop varieties of food crops like rice, maize, sweet potato, cassava, and legumes.

The EAT–Lancet Commission 2.0 report sets targets for healthy and sustainable diets which help meet climate goals like the Paris Agreement. Food quality and nutritive value (proteins, minerals, vitamins) are placed centre stage through the recommended Planetary Health Diet (PHD). This frames nutritious, high-quality diets as foundational to nutrition security (Sustainable Development Goal 2, or SDG2) and essential for achieving human health (SDG3).

The report stresses that although worldwide food production generates enough calories, many people still suffer from malnutrition. In the ASEAN region, there are an estimated 64 million undernourished people; approximately 17.9 million children are stunted. Micronutrient deficiencies and lack of vitamins/ minerals remain widespread, and constitute “hidden hunger”.

As a result, any impact that climate change has on food quality could exacerbate the existing malnutrition problems in the region, as ASEAN consumers move towards the EAT–Lancet Commission 2.0 report’s recommended PHD. The effects of climate change on food quality need to be properly and proactively taken into consideration when planning food security.

Much of the information on the impact of climate change on food systems has been centred on crop yield reduction. Much less attention has been paid to how climate change affects the nutritional quality of the crops. Even less attention has been put into how the increase in the GHGs causing climate change (carbon dioxide, methane and nitrous oxide) affects crops.

It is time to re-examine these paradigms.

First, because the EAT–Lancet Commission 2.0 report and the PHD are strongly based on plants, the nutritive value of food plants becomes of paramount importance. Second, climate change phenomena are likely to continue to wreak havoc on agriculture and disrupt food production, affecting both the quantity and quality of food. The impacts of climate change phenomena on decreasing crop yields in Asia (see Table 1) are generally accepted by most policymakers in ASEAN.

When Climate Change Affects Crop Yields

Table 1. Summary of Major Impacts (Quantity)

Climate Change Phenomena	Yield/production Impact	Examples of Crops Affected
High, rising temperatures	Lower yields, crop failure due to heat stress, shorter growing seasons	Rice, wheat, maize
Precipitation pattern changes	Lower yields due to delay planting or harvest, water stress and submergence	Rice, maize, sorghum
Drought	Lower yields due to reduced crop performance	Maize, legumes
Extreme weather events	Crop losses due to high winds and rain	Rice, vegetables, fruits
Soil degradation	Lower yields due to reduced nutrients	Rice, vegetables
Sea level rise	Lower yields, crop destruction in coastal regions	Rice, vegetables
Heat stress during flowering	Lower yield or crop loss from pollination loss and reduced grain setting	Rice, maize

But some of the same phenomena are also known to affect quality (Table 2). Quality includes both cosmetic appearance and composition (or content).

When Climate Change Affects Quality

Table 2. Summary of Major Impacts

Climate Change Phenomena	Quality Trait Impact	Examples of Crops Affected
High, rising temperatures	Reduced protein and flavour	Rice, wheat, coffee
Precipitation pattern changes	Reduced nutrient content such as minerals, vitamins	Rice, vegetables, fruits
Drought	Elevated sugar content, altered oil content	Fruits, fruit vegetables, Rice
Extreme weather events	Cosmetic defects reducing market value; physical damage leading to post-harvest diseases	Fruits, vegetables
Excess rainfall	Increased fungal contamination; reduced shelf life	Rice, vegetables
Sea level rise	Change in flavour (taste); Reduced marketability	Rice, vegetables
Heat stress	Uneven ripening with uneven nutrient distribution	Maize, Fruity vegetables

The GHGs are also known to affect crop quality, as summarised in Table 3. Elevated levels of carbon dioxide can directly affect nutritional quality (protein and minerals); while methane and nitrous oxide have indirect effects via their contribution to climate change phenomena. Higher levels of methane lead to concurrent higher temperatures and water stress, especially in rice systems. Nitrous oxide is linked to fertiliser management, as improper application of nitrogen-based fertilisers results in the conversion of the nitrogen to nitrous oxide.

How GHGs affect Quality

Table 3. Effects of Elevated Levels of Major Greenhouse Gases on Crop Quality

GHG	Effect on quality	Crops
Carbon Dioxide (CO₂)	Reduces protein and micronutrients (iron, zinc); may increase carbohydrate content.	General
	Decrease in protein; Decrease in B vitamins; Decrease in Zinc and Iron; Decrease in amylose.	Rice
Methane (CH₄)	Decrease in protein and amino acids indirectly due to climate change effects (warming, water regimes).	General
	Indirectly reduces grain quality through warming; effects on grain filling, protein and starch composition.	Rice
Nitrous Oxide (N₂O)	Increase release of N₂O leads to reduced nitrogen for plants; Affects Protein balance, grain uniformity.	General
	Excessive nitrogen use to compensate for nitrous oxide reduces grain quality and increase nitrate accumulation in soils.	Rice

Climate change has provided a powerful impetus for changes in diets, namely, to slow the rise in meat consumption and replace meat with more plant protein. However, in doing so, it is important to ensure that nutritive quality in plant-based food is not sacrificed.

Key actions that reduce the impact of climate change on food quality include practising climate-smart agriculture like adjusting planting dates and crop diversification, growing heat/salinity-tolerant crop varieties, improving water management, and using balanced fertilisation. All these aim to reduce the effect of farming practices on the production of GHGs. Over-arching efforts include use of biotechnology for plant breeding, precision agriculture and farmer training.

The EAT–Lancet Commission 2.0 report called for urgent, collaborative action from governments, industry, and consumers. Regional actions to reduce the impact of climate change on crop quality should focus on cooperation in policy, research, and farmer support across Southeast Asia. Policies will be needed to align climate adaptation and food quality standards. This would help ensure consistent crop quality across ASEAN markets, especially when the region endeavours to increase the level of intra-ASEAN food trade.

Collaborative research should be increased through existing ASEAN mechanisms to develop more climate-resilient, nutrient-rich crop varieties of food crops like rice, maize, sweet potato, cassava, and legumes. The mechanisms include the ASEAN Technical Working Group on Agricultural Research and Development (ATWGARD) and ASEAN Sectoral Working Group on Crops (ASWGC). Climate-smart agricultural practices need to be promoted more through ASEAN initiatives like the ASEAN Climate Resilience Network. ASEAN should also seriously consider setting up regional seed banks and seed-sharing networks. It should work with private sector entities such as the Asia and Pacific Seed Association (APSA). Nutrition security is now an integral part of ASEAN’s new Food, Agriculture and Forestry Sectoral Plan, 2026-2030. At the highest level, the ASEAN Ministers on Agriculture and Forestry will have to encourage member states to look beyond safeguarding food quantity and move towards proactive efforts aimed at avoiding any deterioration in the quality of plant-based food like rice. Taken together, the efforts will seek to ameliorate the “hidden cost” of climate change.

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