Complicated. The higher the temperature, the more the damage is caused to the food. Poaching/boiling limits temperate to 100C. Frying can reach temperatures of 200C+. But in general, I don't think there's much difference between "gentle frying" and "poaching".https://twitter.com/RossJFernando/status/1059226564028620800 …
That being said, fried food is generally more calorie-dense than other options, due to the introduction of more fats, so it's often better to poach or steam if you can!