Oprah was sued for $12 million dollars by a consortium of Texas cattlemen because she said she was never eating burgers again. Apparently due to the Texas False Disparagement of Perishable Food Products Act of 1995, her examination of the meat industry and statements were questionable. The lawsuit was either thrown out or lost, but that doesn't mean that Oprah can say whatever she wants. In fact, it means that a lot of people are not saying anything for fear of ending up in the same position that Oprah was in, spending loads of time and money to defend oneself from these libel suits.
The crux of food libel laws is that there must be reasonable scientific proof of claims or statements that are made about food. The problem lies with the various and differing opinions among food scientists and how this opinions may be shaped by the very industry under examination. For example, hypothetically, are researchers paid by the milk industry the best possible source for information about the need for milk in a healthy diet? I would think no. They would be swayed by their vested interest in the continuation of their industry. Likewise for the cattle industry, and to be fair, likewise for organic researchers funded by organic farms. That is enough to already create controversy over almost any statement about food.
However, a rumor about an amendment to food libel laws is chilling. The rumor I've heard is that there is a proposal to amend food libel laws such that even true statements that harm the industry will be considered for libel (source pending). If product x causes cancer 100% of the time and Oprah said on her show that it did, she could be sued for saying that because it harms the industry. This is a sad statement about the resiliency of American business if we must discard our First Amendment right to free speech (to freely speak the truth) because it harms business. Our concern should be if the business harms the people.
This is the same criticism I have of government agricultural subsidies. I believe in government agricultural aid, but I would opine that unending subsidies of mono-crops and agribusiness are misallocations and foster continued poor business decisions. Subsidies should promote sustainable agricultural and business practices rather than the further centralization and weakening of our food supply.
As a small business owner myself, I want my business to succeed, but not at the cost of the health of my clients and not on the basis of subsidies for continued sub-par performance. As a naturopath who makes dietary suggestions, some of which might be in opposition to certain foods, I wonder when my statements/suggestions/prescriptions or those of my colleagues will put us on trial.