Labdoor analyzed 12 of the best-selling protein bars in the United States for protein, other macronutrients, vitamins, minerals, and toxic heavy metal (arsenic, cadmium, lead, mercury) contamination.
Overall, products in this batch performed well in label accuracy for protein claims; measured protein content deviated for label claims by an average of 1%. The average product measured 17.7 g of protein per serving, ranging from 11 g to 22 g. 2 products recorded plant-based proteins; all other products recorded animal-based proteins. Research notes that animal-based proteins are considered higher quality than plant-based proteins due to their amino acid "completeness" and ability to generate greater gains in lean muscle mass1. No evidence of protein spiking was found in any product2.