You can't. You can't eat crabs when you eat apples, but you can eat apples and crabs separately. Because the nutrients contained in apples and crabs will react chemically, the nutrients will accumulate in the body, which is difficult to digest and easy to stimulate gastrointestinal mucosa, thus causing abdominal distension and abdominal pain. However, apples can be eaten separately from crabs. After eating apples, you need to eat crabs for a period of time, so as to give full play to the efficacy of both. In addition, crabs belong to cold food, and patients with bad stomach should not eat them.