Dietary patterns high in meat compromise both planetary and human health. Meat alternatives may help to facilitate meat reduction; however, the nutritional implications of displacing meat with meat alternatives does not appear to have been evaluated. Here, the ninth cycle of the National Diet and Nutrition Survey was used as the basis of models to assess the effect of meat substitution on nutritional intake. We implemented three models; model 1 replaced 25 %, 50 %, 75 % or 100 % of the current meat intake with a weighted mean of meat alternatives within the UK market. Model 2 compared different ingredient categories of meat alternative; vegetable, mycoprotein, a combination of bean and pea, tofu, nut and soya. Model 3 compared fortified v. unfortified meat alternatives. The models elicited significant shifts in nutrients. Overall, carbohydrate, fibre, sugars and Na increased, whereas reductions were found for protein, total and saturated fat, Fe and B12. Greatest effects were seen for vegetable-based (+24·63g/d carbohydrates), mycoprotein-based (–6·12g/d total fat), nut-based (–19·79g/d protein, +10·23g/d fibre; −4·80g/d saturated fat, +7·44g/d sugars), soya-based (+495·98mg/d Na) and tofu-based (+7·63mg/d Fe, −2·02μg/d B12). Our results suggest that meat alternatives can be a healthful replacement for meat if chosen correctly. Consumers should choose meat alternatives low in Na and sugar, high in fibre, protein and with high micronutrient density, to avoid compromising nutritional intake if reducing meat intake. Manufacturers and policy makers should consider fortification of meat alternatives with nutrients such as Fe and B12 and focus on reducing Na and sugar content.