A growing world population and ongoing climate change have created a need to find new sources ofhigh-quality food, especially protein, that are sustainable and environmentally friendly and help to reduceunsustainable livestock production. Therefore, it is necessary to look for sources of protein from new rawmaterials or to use existing materials that have not been used on a large scale. The highest protein intakecharacterises athletes; thus, the market for high-protein products should be targeted for them. This paperoutlines the main problems associated with protein production to date, mainly from animal sources andsome known plant sources such as pulses, which can cause gastrointestinal problems in athletes. Thisreview aimed to propose several new/alternative protein sources (Single Cell Protein, edible insects, algae,and potato protein) that may have the potential for use in food, including food for athletes while solvingthe described problems associated with existing protein sources. Insects have the best amino acid composi-tion; microbial and algal proteins have great potential but require further development of technology forapplication to food products. Potato proteins are of high value and quality but also contain glycoalka-loids. However, using them brings additional economic and environmental benefits.