“A pro-inflammatory diet as per the study includes foods containing high amounts of fats and proteins.”
So are we to take these as zero (or low) carb diets then?
They used the Dietary Inflammatory Index, which generally looks for nutrition density for the calories:
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8483957/
So a high fat diet (Keto) can have a lot of very low carb veggies and can have Omega 3/6 fats that we have to have, but fat for the sake of fat in excess of what can be used is not helpful. However, carbs for the sake of carbs is also not helpful.
However, Keto/low carb greatly reduces appetite, which can reduce total incoming calories, so the overall nutrition from foods is higher, proportionately.
A combo high fat, high carb diet would seem to be the worst, as many nutrients may be missing for the total calories consumed.
More information:
Perspective: The Dietary Inflammatory Index (DII)—Lessons Learned, Improvements Made, and Future Directions
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6416047/