They actually take far more land, and damage wild life much more. If everyone ate plant based proteins, instead of meat, we would have far less land for wildlife.
Moreover, with recent science and medical discoveries, we are learning animal meats and fats are good for us. Particularly, saturated fat.
Some info on Ketogenic diets (low carb, high saturated fats)
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2716748/ (long term study done with Obese patients)
Indicates Ketogenic diets are beneficial for the bodies nervous system and brains. Explores Ketogenic Diet as a way to reset brain metabolism and neuronal activity and disrupt a cycle of dysfunction.
Explores replacing Polyunsaturated fats as well as Carbs with Saturated fats. indicates a significantly reduced chance of developing CVD after doing so
Indicates a Ketogenic diet can all put cure Type 2 diabetes. Explores the relationship between a KD and insulin
Improves glucose tolerance indepednently of weight loss
Increased Kynurenic avid in discrete brain structures. Major inplications in the treatment of certain neurodegenerative disorders
Differential utilization of ketone bodies by neurons and glioma cell lines: a rationale for ketogenic diet as experimental glioma therapy
The ketone body metabolizing enzymes 3-hydroxybutyrate dehydrogenase 1 and 2 (BDH1 and 2), 3-oxoacid-CoA transferase 1 (OXCT1) and acetyl-CoA acetyltransferase 1 (ACAT1) were expressed at the mRNA and protein level in all glioma cell lines. However, no activation of the hypoxia-inducible factor-1a (HIF-1a) pathway was observed in glioma cells, consistent with the absence of substantial 3-hydroxybutyrate metabolism and subsequent accumulation of succinate. Further, 3-hydroxybutyrate rescued hippocampal neurons from glucose withdrawal-induced cell death but did not protect glioma cell lines. In hypoxia, mRNA expression of OXCT1, ACAT1, BDH1 and 2 was downregulated. In vivo, the ketogenic diet led to a robust increase of blood 3-hydroxybutyrate, but did not alter blood glucose levels or improve survival.
An in-depth study that shows a decrease in body weight, and fat mass, while no loss of muscle mass in elite gymnasts
Ketogenic diet used to treat Epilepsy. Indicates no harmful long term change to the body