One argument made in favour of credentialing laws for online health influencers is that formal qualifications guarantee a baseline of reliable knowledge. This gets the problem backwards.

The food system cannot be understood through the lens of nutrition science alone. 

A serious food communicator needs a reasonable grasp of food politics, environmental science, economics, agricultural practice, food history, the neuroscience of appetite, and more. None of that sits inside a single university curriculum. The Dunning-Kruger effect is most dangerous in the person who knows enough about one thing to feel confident dismissing everything else.

Some of the most misleading nutrition content online comes from people with genuine credentials in a narrow field who then apply that narrow framework to questions it was never designed to answer. For example, a biochemist who treats the entire food system as a series of molecular interactions or a personal trainer who extrapolates from athletic performance to general population health. 

What makes a food communicator trustworthy is the willingness to think laterally, acknowledge the limits of their own knowledge, and remain genuinely open to being wrong.