I think it's very easy to overfeed captive snakes. I've done it. I did it with Figment my Hypo Lavender Corn snake. I followed an online feeding chart. Then I met Don Soderberg, who knows corn snakes as well or better than anyone. He set me straight. Solana (female corn) has stayed lean and healthy and fit on a every 2 week one adult mouse schedule, and Figment has lost some weight and leaned out. I probably hurt him long-term feeding too much (jumbo mice - too fatty) and too often (weekly) for a bit.
Many of these "feeding schedules" are also meant for either breeding animals or exceptional animals. Solana is only about 365G and I have no plans of breeding her. Figment is large for a corn, but was too heavy at over 650G, for him. He's now about 580G and has a much better body shape.
I digressed. It's difficult for keepers to imagine animals as efficient as snakes, who don't get meals on the regular in the wild. Additionally, about 90% of our calories go to maintaining our body temperature, where as snakes, being ectothermic, don't need that. They are also largely ambush predators.
Shayna, my female BP, will go 5 months without eating a thing and lose 5-7% of her body weight. Hard to imagine for people who keep mammals and ARE mammals.