Let’s ignore water and broad brush the chemistry to do a sense check. All Plant structures are basically 3 main components: cellulose, hemi-cellulose and lignin. The ratios vary to form leaves, trees, grasses but they are all made of those 3 components each with similar energy densities, although lignin is slightly higher. Meat is made of protein, fat, dissolved nitrogen substances. The energy density is higher. That info might help us think of a process that has the potential for working. The meat can be high in lignin and oil or fat. The lignin would need to be coupled or treated with the appropriate enzyme so it can be digested by humans. It wold need to be rich in oils like jatropha or olive. Thanks for the thought starter.