I think this is because you are missing this in your config
If you add it, it should render ok.
If you look at your markdown source file, you'll see the resulting plot and table are included using HTML directly inside your markdown document. https://raw.githubusercontent.com/thedivtagguy/website/master/content/post/2020-12-20-food-and-nutrition/index.markdown
Hugo will ignore raw HTML by default. This is something we could not change, but just strongly advice to set this option unsafe to TRUE for goldmark renderer.
This issue will not happen when you use Rmd file as they will be generated using Pandoc and not Goldmark.
We've recently added some check function to give all the advice we have for a website. If you install the dev version, you can run
blogdown::check_site(). I think you are missing other configuration so it could be useful to you.
More on these check functions in here: https://alison.rbind.io/post/2020-12-27-blogdown-checks/