Because (per the article) the metabolism doing the worm is not the roundworm's but the microbe. Which means that the human gut only has to be provide a viable environment for the microbe to do what it wants to do.
This is different, say, than translating the safety or efficacy of a vaccine on a maurine model since the data on the safety and efficacy of the vaccine is specifically for a rodent's immune system.
Common ancestor with potentially a similar gut. That is not definitive against.
The researchers have shown an unexpected effect. They do not know the pathway. The fact the effect exists indicates there is some biochemistry at play that we did not expect to see. What that mechanism is, is not known. So, it is just a question mark, science does not know - and that is simply where we are. We don't know, and we don't even know the chances of the result carrying over to humans. It seems like science needs to identify the mechanism behind this result,then we can start looking at whether that mechanism also exists in humans and also if it functions in a similar way. We might have an enzyme that enhances the effect, or contrary, or not at all. Bottom line, no data is available to make any statements regarding human efficacy, it is a big fat - we do not know
The abstract describes it as promoting lipophagy (the body using its stored fat), so it seems to be better access to fat as fuel. This is a bit distinct from "not gaining fat".
I have yet to find any kombucha with sugar. So far all the ones I've bought have 0 sugar. Sure, sugar is used as a substrate for the cultures but after brewed there's none left, and the resulting drink is slightly sweet and very low calorie.
I always thought that if you let it ferment till there is no sugar left, then there is a chance it might accumulate more than 0.5% alcohol, so the kombucha sold in the US avoids doing that to avoid compliance costs (and maybe taxes), so I'm guessing you don't live in the US, where all the kombucha I've ever bought tastes quite sweet.
I'm drinking a can of Los Bros Ginger & Lemon kombucha. According to the nutritional information on the label, in its 250ml it has <0.5g of sugar and only 6 kcal. It doesn't specify anything about alcohol content but it doesn't taste like alcohol and even if I have a few cans (I usually don't :D) I don't get a buzz.
According to this website [0] even though there will be some amount of alcohol produced in the fermentation process, it should be so low that even drinking "a lot of kombucha" won't get you drunk.
I imagine a sweeter, higher-sugar kombucha will make you crave more than its very low sugar counterparts though - and I doubt Hanlon's razor applies.
