“What post”
The post we are all commenting on.
“what study”
The only study cited in the post.
“what groups”
The group the study is credited to.
I could do the homework for you, but it should only take you 2 mouseclicks to discover this information, if you have even an ounce of skepticism left in you. Actually, the group that funded the study is actually mentioned in foodbabe’s post, so you can even figure out in a single mouseclick.
But it wouldn't be for me, it would be for you - you're the one making the claim.
Do your own homework.