If it does work out to 5% then that means the $4.99 meal goes up by a quarter. Family of four totals to an extra dollar for the whole meal due to providing employees health care.
This is not to say those added quarters don't add up. There will be adjustments, growing pains. But, the hard truth is that a $4.99 meal is an artificially low price, there are lots of hidden costs that society still pays for to make that meal possible even though the employer doesn't see them directly—food subsidies make the meat and eggs way cheaper than actual cost, fuel and transport costs are well below they "should" be in terms of impact on society/environment.
And, for a long long time, the cost of that meal barely factored in the labor involved because restaurants could employ people at almost no salary or benefits. But this too had a hidden cost: employers saved money by not giving employees health care (and, yes, passed that saving down to menu pricing), but those uninsured employees ended up on the public tab anyway. We all still pay when those people go to the ER, have to enroll their kids on Medicaid, etc. Great deal for employers to just toss their employees on the safety net for everyone to pay for.
But now we as a country have passed laws requiring that those people be given health care. So the costs that places like Denny's got to conveniently disperse on the government is now more concentrated. Before: we all helped pay medical costs for uninsured Denny's employees. Now: Denny's customers will pay medical coverage costs for Denny's employees. Makes a little more sense, IMO.