If you don’t want to restock your snacks daily, consider keeping a stack of canned fish in your desk drawer. “I always try to keep either canned tuna or canned salmon on hand. It's great for getting omega-3s,” says Villacorta. “I tend to eat the tuna on rice crackers with a little lime juice.” One can contains nearly 40g of protein and just 5g of fat. Still, eat tuna in moderation to minimize your exposure to mercury.