So it won’t be exact, but it will be very close. Each cup (127 grams) is 47 grams carb, 37 grams protein. If you measured out 0.8 cup (8 tenths of a cup, or 102 grams) you would wind up with the ratio of 38 grams carb and 30 grams protein. That’s as close as you can get since Huel is a fixed ratio. I suppose you could add a few flakes of rolled oats to get those extra 2 grams of carbs, if you wanted.
Since we know that 3 heaping scoops (or 3 and a quarter leveled scoops) is almost exactly 1 cup, then you could probably do 3 leveled scoops (of the included scoop) and that would be about 0.8 cup (102 grams). If you wanted to be exact, then putting it on the food scale would do it. But I’d say that 3 leveled scoops would be very very close, in my estimate.
If you’re intent on tracking food intake so accurately I HIGHLY recommend buying a digital food scale, it will take all of the guess work out with a little bit of simple math and optionally some supplemental protein powder.