My friend has a soda addiction what can i do?

My 22 year old friend is addicted to soda she goes to supermarkets and buys 2 liters bottle of pepsi and ginger ale and drinks soda all day long and she is now very fat from this she refuses to admit to having a problem and says that what she is doing fine since it's just soda. I am worried she is going to ruin her health with this much soda she also eats at mcdonalds every night and she has a double quarter pounder for lunch and dinner. I am afraid she will die if she keeps it up. She will probably get a heart attack from all this fast food and diabetes from all the soda what can be done? Can she be sent to rehab for this kind of addiction?