This is in general good advice, but in the context of healing the liver plants are generally the type of poison your liver exists to filter in the first place, so a meat heavy diet is likely better. Of course you are trading longer term cardiovascular health for short term liver healing so don't do this for long, but if your liver is very damaged avoid plants as well for a short term.
The primary method of action for activated charcoal is to bind to a substance in the digestive system and prevent its absorption into the body.
Unfortunately there can be a significant delay between ingesting the toxin and activated charcoal. However, substances can pass in both directions. So by lowering the concentration in the intestine it also increases the amount that diffuses back into the intestines after having entered the bloodstream.
Aside from the other comment on fiber (which can always be supplemented without fresh greens if concern is phytotoxins)... Given the evidence for impact of neu5gc on liver, maybe watch out what types of meat you are consuming too, and avoid mammals.
This is in general good advice, but in the context of healing the liver plants are generally the type of poison your liver exists to filter in the first place, so a meat heavy diet is likely better. Of course you are trading longer term cardiovascular health for short term liver healing so don't do this for long, but if your liver is very damaged avoid plants as well for a short term.