Pub group JD Wetherspoon saw pre-tax profit drop 13% to £28.5m in the six months to the end of January, following the introduction of a ban on smoking.
The smoking ban in England was introduced in July
Food sales continued to grow as bar sales declined, said the pub group, which has a cautious outlook for the next six months.
Higher energy and raw material costs are also set to hit profits.
The pub group also said that the drunken antics of celebrities were fuelling the misbehaviour of drinkers.
"We expect second-half sales trends to be broadly similar to those in the second quarter, to experience some cost pressures, and therefore to have a slightly more cautious outlook for the second half of the year," chairman Tim Martin said.
About 60% of the group's trade is from food and drink associated with meals, the statement said.
Bar sales are likely to recover, in the wake of the smoking ban, but the exact timing of this is unclear, it added.
Rising concern about the minority of drunken people who misbehave is understandable, it said.
But the pub group says this cannot be solved by police crackdowns on underage drinkers, as many of those who misbehave are older.
The problem was cultural, it said.
"This is demonstrated by examples of poor behaviour by a number of celebrities during the recent televised Brit Awards and by habitual drunken celebrations in the context of sporting events and other occasions, which then receive huge press coverage," it said.
A campaign, similar to that used to combat drunk driving, should emphasise the importance of responsible drinking, it added.