Adverse effect is exactly what I'd call the 'sausages' too. Once they are on a normal schedule or diet, they will lean out and not look like Bloods. No one has yet proven that there is permanent damage done by power feeding. I hope in the future there can be a legit study done on it so keepers know for sure if they are causing harm to their animals.
Also, I never said that the double feeding method WASN'T power feeding. It certainly is however there are other ways to 'force' a snake to eat way more than is necessary for a healthy growth rate. If someone was feeding a 500g snake a 70g rat every three days for months and months, I'd consider that power feeding. Feeding a female that is developing follicles as much as she will take for a few weeks isn't.