There are common non-meat foods with more than 30% protein content such as soybeans and some hard cheeses, even before discounting stuff like fiber and water which doesn’t figure into this ratio. And once you do remove the other stuff, eggs for instance have a ratio like 2/54/44 (don’t quote me on this, I’m guesstimating) and partly-skimmed milk ought not to be very far from the target. So at least if you’re not vegan, you ought to be able to achieve the target… but at what cost and to what end?
I wouldn’t follow slavishly what a study did, especially if it required using “powders”. What’s their justification for the protein and fat levels?
Maybe I’m not thinking outside the box but my guess is that there aren’t enough healthy non-meat foods with the right ratios to allow for a reasonably varied 40/30/30 meatless diet inclusive of all the healthy foods low in protein and/or fat you’d want to eat.
On the other hand, if the general idea has merit, you ought to be able to get fairly close without bending backwards. Surely there’s nothing magical about 30 as opposed to, say, 26!
You shouldn’t focus too much on the fact some people have achieved an UA reduction with that diet because:
-one’s UA level is not determined primarily by the carbs/protein/fat ratio of one’s diet and people have reduced their UA without eating so much protein and fat
-you have to compare the diet’s effect on UA with the effect of other diets as well as with your previous diet(s), not with whatever the study participants ate before that study
-gout symptoms during the process of UA reduction aren’t driven by UA levels alone and I bet there’s for instance a reason gout patients are told to watch the fat they eat (I’m not saying all fat is bad though)