What was Yogananda referring to when he talked about "proper meat substitutes" in the book Spiritual Relationships from The Wisdom of Yogananda Series.
In How to Achieve Glowing Health and Vitality Yogananda refers to: nuts and seeds as meat substitutes. He refers especially to nuts such as almonds, walnuts, cashews as meat substitutes. Of course all legumes (lentils and beans) are great substitutes for meat.
I hope this answers your question.
Joy to you,