Type AB reflects the mixed inheritance of their A and B genes. They have low stomach acid, but also have type Bs adaptation to meats. Therefore, they lack enough stomach acid to metabolize them efficiently and the meat they eat tends to get stored as fat.
Type ABs should avoid caffeine and alcohol, especially when they are in stressful situations. Type ABs should focus on foods such as tofu, seafood, dairy and green vegetables. Avoid all smoked or cured meats. These foods can cause stomach cancer in people with low levels of stomach acid. There is a wide variety of seafood that is good for type ABs, and it is an excellent source of protein. Some dairy is also beneficial for type ABs -- especially cultured dairy such as yogurt and kefir.