I’m sure in 5 years all processed microwave meals and fast food will be “fortified with GLP-1”.
I do think there's a strong argument that lack of fiber and protein are huge contributors to the world's obesity problems.
Nobody really knows how GLP-1 agonists work, but given the other effects (e.g. insulin stability, change in other addictive behaviours etc.) it's definitely not just this.
Source needed.