Well it's not clear there is one optimal level for most nutrients. You should hit all the Recommended Dietary Allowances and stay under the Tolerable Upper Intake Levels (links to both given in the grandparent), but in between that large range (often a factor of ten), who knows, it doesn't seem to make any difference (which is why the ULs are so high).
Given most usual Western diets, the problem isn't malnourishment (although it does exist, Vitamin D deficiencies in general, and problems with low SES populations subsisting on soda and chips come to mind). The problem is simply too many calories (and salts) consumed. Fast food is actually quite healthy ... if consumed in the appropriate amounts.
In other words, as long as you stay in the range, there's probably little difference between a formula designed specifically for adults, and a formula designed for kids which when scaled up is also in the correct ranges.
Thus spake Eliezer:
It seems that many here might have outlandish ideas for ways of improving our lives. For instance, a recent post advocated installing really bright lights as a way to boost alertness and productivity. We should not adopt such hacks into our dogma until we're pretty sure they work; however, one way of knowing whether a crazy idea works is to try implementing it, and you may have more ideas than you're planning to implement.
So: please post all such lifehack ideas! Even if you haven't tried them, even if they seem unlikely to work. Post them separately, unless some other way would be more appropriate. If you've tried some idea and it hasn't worked, it would be useful to post that too.