Energy content of foods were matched to one serve of beef (471 kJ). ˆ Greenhouse gas emissions equivalent to the driving distance by an average passenger vehicle with average fuel economy. Acid., acidifying emissions; Equiv, equivalent; Eutroph., eutrophying emissions; GHG, greenhouse gas. All measures of environmental sustainability were calculated from Poore and Nemecek [13].

> Not accounting for bioavailability, the iron content provided by one serve of beef is 1.7 mg (Table 2) and, of the food items analyzed, was the richest animal-derived iron source. The overall iron content of plant-based alternatives was high, with mixed beans, lentils, and tofu (firm and silken) being the richest sources. The estimated absorbed iron from isoenergetic serves of mixed beans, lentils, and tofu (firm and silken) was slightly higher than from beef.

Using data from Poore et al. [13], the production of beef produced far greater GHG emissions (10.0 kg CO2 eq per serve) than other animal-derived alternatives and plantbased alternatives (Table 3). Extrapolating these results, if pregnant women replace one serve of beef with one isoenergetic serve of firm tofu each week throughout their pregnancy, GHG emissions would be reduced by 372.2 kg CO2 eq, equivalent to the emissions produced by a typical passenger vehicle driven for 1498 km (Table S2). For other measures of environmental sustainability, all food alternatives have land use less than 2.1 m2, except for lamb (25.4 m2), per isoenergetic serve (Table 3). Most food alternatives have acidifying emissions of lower than 10 g SO2 eq per isoenergetic serve. White fish produced the highest eutrophying emissions (24.1 g PO4 <sup>3</sup><sup>−</sup> eq). Lastly, pork, lamb, and white fish have higher stress-weighted water use (L) than beef (3473.3 L) per serve. Modeling of this replacement of one serve of beef with one isoenergetic serve of firm tofu indicates a small positive impact or no impact on nutrient intakes (Table 4). For example, it would not meaningfully impact iron intake (+1.1 mg/serve), whilst folate (+28.1 μg/serve) and dietary fiber (+3.3 g/serve) would both increase. The exception is zinc, which decreases by 0.5 mg per serve. The net results of this substitution would be that among women who consume a mixed diet, the proportion who meet NRVs for zinc fall by 11%, and the proportion of pregnant women meeting NRVs for calcium and fiber increase by 5% and 2%, respectively.

**Table 4.** Modeling nutrient intake of pregnant women replacing one serve of beef per week with an isoenergetic serve of firm tofu #.

