To my knowledge, a low carb diet shouldn't change the effects of most recreational drugs, unless the diet significantly changes how you feel sober.
A low carb diet could definitely impact recovery from stimulants and stimulating psychedelics, however. Stims burn through carb reserves so you may need to increase your carb intake on recovery days, if you're on a very low carb diet.
Btw, I take hydromorphone orally every day, 24 hours a day, with occasional nasal use in addition, and I also eat every other day. I have a fairly high carb intake on my eating days, but on my fasting days I consume virtually none (a teaspoon of honey for allergies, 5 almonds with my nightly vitamins). I don't notice any difference in the efficacy of my hydromorphone on my fasting days. However, I'm not on a recreational dose and my use is purely for legitimate pain, so I don't ever get high nor would I want to. At least not on opiates.