Final answer:
The concern Eric may have developed regarding his vegetarian diet is protein deficiency.
Step-by-step explanation:
Eric, who is 21 years old and weighs 165 lbs, initially stopped eating meat for health reasons. Regarding his vegetarian diet, the concern he may have developed is a) concerns about protein deficiency.
Vegetarian diets rely on plants for protein and energy. While some vegetarian diets can provide adequate calories and nutrients, others may not supply enough protein and minerals like calcium and iron. It is important for vegetarians to carefully select a variety of plant foods to ensure they are getting all essential amino acids.
In summary, Eric's concern about his vegetarian diet may be protein deficiency. Vegetarians need to be mindful of their protein intake and ensure they are getting all essential amino acids by selecting a variety of plant-based protein sources.