You are allowed to eat and participate in normal low-risk activities as you usually would during any normal, healthy pregnancy per your OBs guidelines. Unless there is a specific agreement between the carrier and her Intended Parents to avoid certain items, she may carry on per her doctor’s recommendations. Obviously, the usual substances like nicotine, alcohol, and drugs are NEVER allowed. There could be specific food requests based on religion or lifestyle preferences that Intended Parents may request of their surrogate prior to matching. These specifics are usually brought up on applications and during the match meeting so there are no surprises later. If either party were to not feel sure about the requests, it would need to be discussed before a definite match was determined.