Toward the end of the new documentary Food, Inc 2, the film-makers explore alternatives to the food churned out by the corporate giants doing so much damage to our health and environment.

After meeting people turning plants into “fish” and “chicken wings”, and promising “dairy without a cow” and “honey without bees”, the scene shifts to large steel vats where chicken, pork and beef are grown from cells. This, we are told, might be a future alternative to battery farms and the vast acres of cattle heating up the planet.

But how does it taste? A piece of chicken is consumed and given the thumbs up. But then the film-makers reveal that they learned later the chicken hadn’t come from the vat after all. “We felt a little misled,” said the director, Robert Kenner. “It feels like a Silicon Valley product not a food product.”

The scene neatly encapsulates the challenge facing those who want to bring down the food production system Kenner exposed 16 years ago in Food, Inc, a groundbreaking documentary that laid bare how a few sprawling corporations took over the food chain in the US to the detriment of farmers, consumers, animals and the planet.

In Food, Inc 2, Kenner and his co-director, Melissa Robledo, assess what progress has been made, and the news isn’t good. As the incident with the chicken showed, change isn’t necessarily what it seems.

Kenner was prompted to revisit the question of how we come to eat what we do, and whether his original film had done anything to loosen the grip of corporations over that, by the Covid pandemic.

“We really thought we could change the system one bite at a time and there were good things that came out of both our film and the books and other movies. There was a real food movement, farmers’ markets and a consciousness about what we were eating. But 16 years later the pandemic showed a window into the brutality of this consolidated system,” he said.

The film-makers travel to Waterloo, Iowa, where the multinational Tyson Foods has one of its many slaughterhouses. Tyson refused to close its plants at the height of the pandemic even as thousands of its workers contracted Covid and 38 died. Local communities accused the company of helping to spread the virus and costing lives.

In Waterloo, we meet the Black Hawk county sheriff, Tony Thompson, eating a vast and very unhealthy looking meal. Thompson said that Tyson was one of the area’s largest employers and “you don’t want to alienate them”.

But lives were at stake, so Thompson went into the Tyson plant with public health officials.

“We saw people working elbow to elbow, reaching over the top of each other, no masks, no regulation, no real concerted policy on how to protect each other. And then we’re hearing from people that they’re stepping back from the line, puking on the floor, going right back to work,” he said. “By the end of the month, they had 1,300 positives out of 2,500 employees. And then it started to seep out of the plant and into our community.”

Deaths escalated by the day. Still Tyson refused to shut down the plant. The industry began running ads scaring the public into thinking the US would face a severe meat shortage if the factories closed.

Then Tyson played its ace and persuaded the Trump administration to invoke the Defense Production Act to keep the slaughterhouses open. The law was written in 1950 to give the government the power to require manufacturers to switch production to war needs but now it was being used to force workers to risk their lives for company profits.

“The most frightening part is they perverted the democracy,” said Kenner. “They used the Defense Production Act to make the workers do what the company wanted and go back to work, as opposed to making a company do what was good for the country.”

Tyson claimed it was doing this to feed America even though a large proportion of its production was exported to China. Thompson called the profits from keeping the slaughterhouses open “blood money”.

“They didn’t care about our citizens and way too many people paid the price for that,” he said.

So how do you change a system in the face of such a brazen display of power?

Food, Inc 2 covers a lot of ground, from the conditions of workers to local farming initiatives, and some of them have real impact, such as the campaign to ensure that mostly migrant labourers are paid a decent wage for picking fruit.

Kenner said he was “shocked” at one of the film’s most striking revelations. Less than 15 cents in the dollar of food production goes to farmers. The bulk of the profit is in turning healthy food into ultra-processed junk by making crops and meat taste of something completely different while piling on artificial flavours, sweeteners, emulsifiers and preservatives. With these, Food, Inc 2 notes, we are literally eating ourselves to death.

This problem is worse in the US than most other places. Ultra-processed foods account for 58% of Americans energy intake. In Italy it is 17%.

One of the greatest challenges to creating a different food system is the monopoly created by Tyson and other huge corporations buying up their competitors until a few companies dominate production. They then use their financial power to subvert regulation and ensure subsidies that profit the making of ultra-processed foods continue. Those few companies are even more dominant now than when Kenner made the original documentary.

“We’re seeing a system that’s been perverted by corporate money. Ironically, we’re more like a Soviet-style economy than an American capitalist economy. There is no competition any more and we’re serving food that is unhealthy. It’s unhealthy for the eater. It’s unhealthy for the people who grow the food, and it’s unhealthy for the planet,” he said.

As Robledo notes, the problem isn’t the lack of regulation but the unwillingness of successive governments to enforce the law. “What we need is enforcement. The regulations were written not only to foster competition but to prevent corporations from having access and control or undue influence over our regulators and our government and ultimately, the president,” she said.

It’s hard not to agree with Jon Tester, a farmer and a US senator for Montana, when he tells the film-makers that there’s only one place to break the system and that’s Washington DC.

Ultimately though, Food, Inc 2 is more a recognition of the scale of the challenge than a roadmap to change. The film-makers’ search for solutions takes them to companies that say their push for better food is driven by environmental concerns.

Pat Brown, the founder of Impossible Foods, speaks of the need to rid the food system of animals. He says that replacing cattle could provide a 30-year pause in the rise of greenhouse gases. So he makes “meat” from plants. But the famed Impossible Burger, now in every Burger King in the country, is ultimately just another ultra-processed food.

A string of alternative meat companies have followed in Impossible Foods’ wake. But where is the funding coming from? Tyson Foods, along with the hedge funds and tech investors who have so long put profit first are rushing into the business.

“The emerging industry is in danger of being in the grips of corporate control,” said Robledo. “We were trying to show that you set out with great values and they can be compromised along the way.”

• Food, Inc 2 is out in US cinemas on 12 April with a UK date to be announced