Minimum reasonable study group ("Intervention groups consisted of 322 participants" plus a placebo group). Smaller than that doesn't tell you much, you need larger signal to overcome statistical noise in smaller groups, but larger studies cost so much they can't get funding: several hundred sounds good. But they're broken down into six studies, so now we're in the range where noise will exceed signal: you're setting up for equivocal results. But wait! - there's more:
Short term studies, mean duration 17 weeks - shortest 8???
What, to see significant physiological changes in a long-lived species (humans)? And you did it with the most robust & resilient group you could find: youth. Huh.

Lemmie guess: not a lot of changes evident; more studies required. Results that they may/may not - have seen given small sample groups, that may/may not - result from the short-term interventions, MAY have beneficial outcomes. Glad we settled that, then. Money well spent!

I bet the study's authors would round it out with an assertion or two not really proved by their study. "The MedDiet's low intake of saturated fats and high intake of healthy fats likely contribute to its beneficial effects."

Called it.

But hey, at least someone's doing dietary intervention studies: that's good. And let's face it, the researchers need to publish or they won't obtain/keep their academic appointments. So there's that.

No sure it's News though.