William Banting, author of Letter on Corpulence, Addressed to the Public in 1863, apparently found he was able to indulge in some carbs during maintenance after low-carb weight loss (p. 35, emphasis his):

I have ... frequently indulged my fancy, experimentally, in using milk, sugar, butter, and potatoes—indeed, I may say all the forbidden articles except beer, in moderation, with impunity, but always as an exception, not as a rule.