GAIN urges broader assessment of alternative proteins as study warns against climate-only focus

The use of alternative proteins as a climate solution should not come at the expense of nutrition, according to researchers from the Global Alliance for Improved Nutrition (GAIN), who argue that evaluating foods primarily through their greenhouse gas emissions risks overlooking their role in addressing micronutrient deficiencies.

• GAIN researchers published a commentary in One Earth calling for broader assessment of alternative proteins across nutrition, environment, affordability and livelihoods.
• Analysis combined two evidence reviews covering 372 studies comparing nutritional and environmental performance with conventional animal-source foods.
• Authors recommended stronger nutritional standards, improved labeling and greater emphasis on minimally processed plant foods and context-specific dietary guidance.

The commentary, published in One Earth, argues that debates around alternative proteins have become overly focused on reducing climate impacts, despite growing evidence that their nutritional and environmental performance varies considerably depending on the product, production method and population consuming them.

The paper draws on two evidence reviews published this year. One examined 247 studies comparing alternative animal-source foods with conventional animal products across nutrition and health outcomes, while the second reviewed 125 product-level environmental studies comparing the environmental impacts of alternative and conventional animal-source foods.

Taken together, the reviews suggest that the benefits of alternative proteins are highly dependent on context rather than being universal.

The researchers found that minimally processed plant foods, including legumes, tofu and tempeh, consistently performed well, combining relatively low environmental impacts with strong nutritional value and established roles in many traditional diets.

By contrast, formulated plant-based meat alternatives often retain an environmental advantage over beef, but that benefit can narrow depending on factors such as ingredient sourcing, manufacturing processes, packaging and energy use.

The findings were similarly mixed for products derived from fungi, insects, algae and cultivated cells. According to the researchers, their environmental performance depends heavily on feedstocks, production design, scale and the carbon intensity of the electricity used during manufacture.

Nutritional outcomes also varied across categories.

The authors noted that plant- and fungi-based products generally provide more dietary fiber and less saturated fat than conventional animal products and may improve cardiometabolic health markers. However, many also contain less bioavailable protein, iron, zinc and vitamin B12, although soy-based products were identified as a notable exception for protein quality.

The commentary also highlights nutritional differences in dairy alternatives. Most plant-based milks, with the exception of fortified soy beverages, contain lower levels of protein, calcium, iodine, vitamin B12 and riboflavin than cow's milk.

Researchers Ty Beal, Stella Nordhagen and Mduduzi Mbuya argue that judging alternative proteins as either sustainable or unsustainable requires a broader framework that considers nutrition, environmental performance, livelihoods, affordability and consumer acceptability, rather than climate impacts alone.

The paper outlines several recommendations for policymakers, researchers and industry.

Among them is the adoption of nutritional functional units in life cycle assessments so environmental impacts are reported not only per kilogram of food, calorie or gram of protein, but also relative to overall nutritional value. The authors also call for greater transparency around how fortification, bioavailability, processing levels, electricity sources and comparator products influence environmental assessments.

The researchers also recommend stronger composition, labeling and fortification standards for products marketed as replacements for nutrient-dense animal-source foods. They argue that packaging should clearly communicate nutritional differences while also highlighting benefits such as fiber content. They identify minimum fortification standards for plant-based milks as a particular priority.

The paper further recommends that public procurement policies and dietary guidelines place greater emphasis on minimally processed plant foods such as legumes, nuts, seeds, tofu and tempeh, while distinguishing between reducing excessive consumption of animal-source foods and replacing foods that remain important sources of nutrients in populations vulnerable to undernutrition.

For emerging technologies such as precision fermentation, insect farming and cultivated meat, the authors argue that environmental claims should remain closely linked to production practices, including the use of low-carbon electricity, circular feedstocks and transparent safety assessments. They also call for more research in low- and middle-income countries rather than concentrating primarily on high-income markets.

Summarizing their position, the researchers conclude that the sustainability of alternative proteins depends on "what animal source food it replaces, in what context, and for whom", adding that "sustainability without nutritional adequacy is not sustainability".