Nutritional yeast is a very high source of protein with about 50% of energy coming from protein content in the food. In addition to protein, nutritional yeast also provides a variety of vitamins and trace minerals, some of them in high concentrations.

Vegetarians and vegans commonly consume small amounts of nutritional yeast, for example in cooking or on popcorn. Are there any concerns with consuming much higher quantities of nutritional yeast? For example, what would happen if somebody tried to obtain 100% of their protein requirement from nutritional yeast?

Is there a tolerable upper limit for daily intake of nutritional yeast?