There are two kinds of studies I hate in the world of nutrition; this is one of them. This is the glorified ad study, where we look at a specific food item and a specific "good" trait and line them up. Once aligned, we let the marketers go to town because this food magically "solves" the problem (but we will still qualify with language like "may help" to prevent law suits).
Add an apple to your current obesigenic diet and you will still have an obesigenic diet. Replace some corn chips, bread or cake in your obesigenic diet with an apple, and you are a step closer to it not being obesigenic (but the same applies to kale, steak, and strawberries). Include apples as part of your whole foods, higher fat, lower sugar diet (aka healthy), and you will still have a whole foods, higher fat, lower sugar diet.
Nothing in the diet exists in isolation. You have to consider the whole diet.
Not disagreeing with you, but you have to consider the whole diet plus the gut microbiome. There's been a lot of focus on what we put into our bodies, we also need some focus on the organ that we weren't born with.
If I came off sounding like I don't appreciate the profound influence of our gut biota, I apologize. Gut science is a fascinating new field, and the only thing we really know is we really don't know much. :) So I totally agree with you; in fact, I'd say, when contemplating whole diet, you need to give as much consideration to your gut as you do yourself.
Add an apple to your current obesigenic diet and you will still have an obesigenic diet. Replace some corn chips, bread or cake in your obesigenic diet with an apple, and you are a step closer to it not being obesigenic (but the same applies to kale, steak, and strawberries). Include apples as part of your whole foods, higher fat, lower sugar diet (aka healthy), and you will still have a whole foods, higher fat, lower sugar diet.
Nothing in the diet exists in isolation. You have to consider the whole diet.