This Dietitian Eats These 5 Foods Every Day — and You Should Too

"These fish are high in omega-3 fatty acids, vitamin D, vitamin B2, and other important nutrients like selenium and calcium," explained Davis, who noted that small fish are also less likely to be contaminated with mercury than their larger counterparts. Of those, vitamin D is especially crucial: it helps the body absorb calcium, which is key for strong bones, and it's found in very few foods. Try adding fish like sardines and mackerel to salads and pasta dishes.

"Nuts are high in healthy fats and antioxidants," Davis said, including omega-3 fatty acids, which support brain function and protect against heart disease. Nuts are also a good source of protein and fibre, which quickly satisfy hunger and keep you full longer. "I tell my clients to keep them in their desk or car. They're the perfect on-the-go snack," she said.