My blood type is A+ and I found this Men's Health "Eat According to Your Blood Type" article to most concisely articulate the topic and am including the excerpt here for my own future reference.
TYPE A3 Character Traits: Hardworking, responsible, calmYour Diet: When hunter-gatherer Os started thinning out, our ancestors started relying on agriculture and expanding their diet to include a semi-vegetarian approach. Type As have the digestive enzymes and bacteria it takes to digest grains and plants that other blood types might have a rough time breaking down.Your Personality: When everyone else is panicking, you keep it cool. You’re responsible, hardworking, detail oriented and extremely organized. But you also have a classic “type A” personality—stressed and conscientious, craving success and perfection. You're the most artistic of the blood types (and even a bit sensitive).What to Eat: Fill your plate with fruits like berries, figs, plums, apples, avocados, pears and peaches. Choose veggies like broccoli, artichokes, carrots, greens and garlic. Fish and poultry should be limited since type As produce fewer meat-digesting enzymes, which is why they have such a hard time digesting red meat. To get protein, rely on plant protein from nuts (like nut butters), seeds, beans and soy. Since your body can easily break down and get optimal nutrition from grains, carbs and proteins, cereal, breads and pastas should be staples of your diet.What to Avoid: To balance cortisol levels (you may have high levels, which can lead to OCD, disrupted sleep, muscle loss, fat gain and insulin resistance) limit sugar, caffeine and alcohol and don’t skip meals, especially breakfast. Stressful elements like extreme weather conditions, loud noise, overwork and violent TV and movies should also be avoided.Dinner Tonight: Tofu-pesto lasagna, broccoli and frozen yogurt.Your Workout: Since you stress easily, try something calming like yoga.