Seems like the solution is pretty easy...don’t offer anything “all you can eat.”
Yes, sir, that’s all you can eat for $28.
The guy who came up with all you can Lobster night at Red Lobster lost his job after they lost their a$$ on that special.
Reminds me of an old joke that ought to good for at least a groan. A guy goes into a restaurant that says all the catfish you can eat - $5.00. He orders that and is brought a serving of catfish. He eats it and orders more. The owner brings it to him and says, "That will be another $5.00" The customer stutters, "Wait a minute! Your sign says All You Can Eat - $5.00!" The owner replies, "That IS all you can eat for $5.00. Want more, another $5.00." Bada boom, bada bing.