We are experiencing an increase in the availability of protein ingredients from more sustainable production sources, and we need to learn how to utilize them to create highly nutritional and climate friendly foods. Much work is needed to assist in innovation, by developing principles leading to the design of the best structures to ensure optimal function. We propose a holistic approach to the design of new sustainable proteins for food, so that they may compare favorably to their animal sourced counterparts. While the immediate challenges are related to improving processing functionality and providing the essential amino acids balance, we will soon also need to learn to pay close attention to the molecular interactions occurring during processing, as these can be modulated to form different supramolecular structures. This shift will create new opportunities to innovate and create a new generation of highly nutritious and functional foods. This review focuses on the recent trends on the use of plant protein blends, and highlights the research gaps and challenges related to using ingredients of different composition and history to develop more climate friendly foods.