I can verify through personal experience of the over feeding being an issue my first snake was a corn snake and I was feeding her every 7 days with the largest mouse I was able to get her to eat. Suffice to say she got insanely fat and ended up taking a 3 month hiatus in feeding despite me handling her just about every day and for long periods. Quite frankly looking back its amazing she made it to 15years of age. I had seen other corns in pet shops and at the time due to my ignorance I assumed they weren't feeding them enough. Bearing in mind I had my corn out every evening while I was at school for most of the evening so she got massive amounts of exercise despite this she ended up hugely fat. Eventually she fasted for 3months And I finally did more research and found out I had been over feeding her a lot, thankfully the fact I had her out so much and kept her so active reduced the scale of the issue to the above mentioned fast.

I cannot emphasize this enough unless you have the time to handle them for 2-3 hours a day as I did (being a mere teen out in the middle of nowhere) then feed as recommended. I obviously can only advise on what not to do which is feed adult corns every 7 days. I would suggest every 10-14 days. I freely admit I screwed up on how often to feed an adult corn but it took 15 years for the results to occur.