The referenced report normalizes all values by calories. A cup of lettuce has 5 calories. A comparable volume of meat has over 300. The report also lumps together very different food items. A cup of corn has more than 600 calories, but all vegetables are confined to a single bin in the figures for energy use, blue water footprint, and GHC emissions. Lots of the conclusions from this site seem pretty misleading.

The report lives behind a paywall. It's difficult to provide analysis without seeing the methodology. I'm skeptical.