This topic drives me nuts because it just builds fear and people hit me with this all the time. Grr.
My nutritionist doesn't think surgery is right for me unless i start eating meat. I think its just old school training. I gave her a copy of the China Study and Forks over Knives and calculated my actual daily protein intake on My Fitness Pal.
Using accepted protein calculations, the same ones she uses, heres what I found.
Your protein needs should be based on a healthy weight rather than the weight you are before surgery. Fat doesn't require protein so adding excess weight into the calculations is silly. At 5ft 4 all I need is 60 to 70 grams of protein and that is probably high for me. During recovery when my body is trying to heal or when Im trying to gain muscle, my body would require more.
The lobbyists decide what goes in the medical books but the information is out there from reliable scientific studies. Many green leafy veggies have about 10% protein built in. You need to consider all sources of protein when calculating your daily intake. I admit this will be harder and some supplementation will be required after surgery, but I swear my nutritionist stopped reading when she graduated school, about 20 years ago. Sad but true.( She still thinks cows milk is a good source of calcium but it has been proven to do more harm to your bones than good as the calcium molecule is to coarse for us to use..)
To much animal protein is just as dangerous for the body as too little. Animal protein has been linked to heart disease and cancer. Read the China study, do your research and do whats best for you. There is a whole healthy vegan community out there thriving, working out, building muscle all while eating a plant based diet without excess supplements.
Sorry for the rant, hope it helps.