Well, YES, and NO - it is possible to do this, BUT affordability, knowledge and general availability make it difficult, particularly in low-resource settings.
Obtaining continuous and adequate high-quality protein and micronutrients from plant-based foods can be challenging - particular for young children, who have small stomachs as fairly high volumes are required.
Since Animal Sourced Foods tend to be dense in many nutrients, smaller amounts can be eaten to meet requirements.
Animal Sourced Foods is particularly important for reducing undernutrition among vulnerable groups in resource-poor settings. Infants, young children, and adolescents are undergoing periods of physiological change and accelerated growth; pregnant and lactating women have higher nutrient requirements due to fetal growth and milk production.