Brainfood snacks are snacks that are beneficial for the brain. These snacks are rich in omega-3 fatty acids which are vital to the health of the brain. They also have other health benefits such as improving mood, cognition, memory, and other health benefits. A 4-ounce can of tuna contains approximately 260 calories , and has an adequate amount of omega-3 fatty acids. Furthermore, a portion of tuna is also high in protein.