Well one thing you can't do is take away the benefits. EBT and other kinds of state assistance have caused generations of people to become entrenched, and reliance upon this assistance is baked into much of the American culture. To remove it suddenly would be as cruel as it is to continue to perpetrate it among the masses today, knowing what we know.
The exact solution is complicated. It would, on the one hand, involve grandfathering in all current entrenched users of state subsidies. On the other, we'd have to allow young people to opt out of any of these payroll taxes, and therefore not be eligible to receive these benefits. They would see a massive uptick in their take-home income, which they can spend as they wish instead of having to buy the cheap bullshit that EBT affords its users.
With those extra dollars young consumers would have many more votes as to where their dollars go, and will have a greater ability to influence corporate behavior. Companies that peddle sugar-filled crap will have less of that predictable monthly revenue to depend upon, and therefore the prices for their food products will rise. This will begin making real food more attractive to EBT consumers, and will introduce actual competition into the market.
The only reason that these multi-national food product corporations can make money on uninformed, unhealthy consumers is because the government props up these business models. This can be witnessed throughout the debate among many stakeholders - farming subsidies, environmental regulations, tariffs, and even our government's own horrible diet recommendations - there are so many bad actors here that no solution will be comprehensive. What I believe to be the most important of all the fixes that we need to derive, however, is the education factor. Because EBT exists, consumers are not driven to be educated. Until we give people a choice, they will never bother to lift a finger and educate themselves.
All the well-meaning charities, after-school programs, and education facilities on the planet will not stop Coca-Cola from lobbying Congress. Even Michelle Obama's ridiculous nutrition program facilities the wrong message. (Look at how little abstinence from sugar is promoted by her, and how much exercise is promoted, as if kids have the ability to run 10 miles per day to work off the abhorrent amount of sugar in their breakfast cereals, let alone the rest of the sugary junk they consume on a daily basis.) The only way to get Congress to listen is to have the electorate realize just how fucked over they have been by their representatives who peddled the food product multi-nationals' prerogatives, and get MAD AS HELL about it.