Based on the information available, there are no known side effects specifically related to taking Lipitor (atorvastatin) with beef. Lipitor is a medication used to treat high cholesterol levels, and its interaction with food is generally related to grapefruit and grapefruit juice [1].

Beef, on its own, does not have any known interactions with Lipitor. However, it is always recommended to consult with a healthcare provider or pharmacist for personalized advice, as individual responses to medications can vary [2].

It is also important to maintain a balanced diet as part of a comprehensive treatment plan for high cholesterol. This may include lean proteins such as beef, in moderation and as part of a heart-healthy diet [3].

In conclusion, based on the available information, there are no known side effects when taking Lipitor with beef. However, it is always best to consult with a healthcare provider for personalized advice.

Sources:
[1] "Atorvastatin" (Lipitor) - DrugBank. <https://go.drugbank.com/drugs/DB00313>.
[2] "Lipitor" - Mayo Clinic. <https://www.mayoclinic.org/drugs-supplements/lipitor-oral-route/description/drg-20061025>.
[3] "Eating Foods High in Cholesterol" - Mayo Clinic. <https://www.mayoclinic.org/diseases-conditions/high-blood-cholesterol/in-depth/cholesterol/art-20045197>.