Substituting Meat or Dairy Products with Plant-Based Substitutes Has Small and Heterogeneous Effects on Diet Quality and Nutrient Security: A Simulation Study in French Adults (INCA3)

International audiencePlant-based substitutes are designed to have the same use as animal-based foods in the diet and could therefore assist the transition toward more plant-based diets. However, their nutritional impact has not been characterized.We assessed and compared the effects of plant-based substitutes on the nutritional quality of the diet. We simulated separately the substitution of meat, milk, and dairy desserts with 96 plant-based substitutes in the diets of 2121 adults (18–79 y old) from the cross-sectional French Third Individual and National Study on Food Consumption Survey (INCA3; 2014–2015). The quality of initial individual diets and the 203,616 substituted diets was evaluated using the Probability of Adequate Nutrient Intake (PANDiet) scoring system, which assesses the probability of adequate (sufficient and not excessive) nutrient intake; also, nutrient security was evaluated using the SecDiet scoring system, which assesses the risk of overt deficiency.Impacts on PANDiet depended on both the food substituted and the types of substitutes. Soy-based substitutes provided a slight improvement in diet quality (0.8% increase of the PANDiet score when substituting meat), whereas cereal-based substitutes resulted in a 1.1% decrease. Globally, substitutions led to better adequacies for fiber, linoleic acid, α-linolenic acid, vitamin E, folate, and SFAs, but lower adequacies regarding vitamin B-12 and riboflavin, as well as bioavailable zinc and iron when substituting meat, and calcium and iodine when substituting milk/dairy desserts.When they substituted dairy products, calcium-fortified substitutes allowed maintenance of calcium adequacy but there was a higher risk of iodine deficiency when substituting dairy, which may warrant iodine fortification. Substitutions modified the energy share of ultra-processed foods from 29% to 27%–40%, depending on the food substituted and the substitute used.Plant-based substitutes had a small effect on overall diet quality and heterogeneous impacts on nutrient adequacy and security. Plant-based substitutes that include legumes appear more nutritionally adequate to substitute animal products than do other substitutes