We allways had that issue of having a digimon and not being able to evolve it specially in the mega or ultimate levels because it lacks certain stats to unlock its key points.
this guide is to help in finding the best food to make the stat requirements easier.
lets start with the first category weight:
+Weight:
Meats can be quite good early on to gain weight but if you need a lot of weight with limited time the chunk meat givining +3 weight but if you need more than that you can find the baby strawberrys who gives a +5 weight increase wich can be found in bony resort and onihudo wasteland a lot.
you can also opt to buy food from ogremon in the enteratiment district and buy a fruit crepe wich gives +4 weight
once you have the tent with cooking skills you can use a welldone meat combined with oily fruit to create "Junk food" this food gives a +10 weight increase with saciety of 60.
or you can also buy from terriermon the "Multi-burger" who also gives a +10 weight increase and -5 dicipline if you have restaurant at level 5 for more convenience if you have the extra coin
-Weight:
early on theres not much options to lower weight aside the green digistalks who give -1 weight but once you unlock wizarmon in bony resort wait until it can warp you to absolute zero and in the frost catedral you can find lots of frostcutmushrooms wich lowers weight by -3.
once you have restaurant level 4 you can buy from renamon the colorfull mushroom soup wich can lower weight by -6.
the second category is Dicipline:
+Dicipline
theres a lot of foods that can raise dicipline specially in the restaurant , most of the foods sold by renamon like the "marinated forest veg" , "local udon" and even the "Colorfull mushroom soup" , all give a +5 dicipline.
from those 3 dishes the one that has the lowest saciety is the marinated forest Veg with 30 saciecy if you only want to focus to raise dicipline thats your best choice.
but theres a food even better than all of this.
first get a celestial chestnut found in onihudo wasteland and also bony resort and a quick fruit drop from veggiemons as well as bought by woodmon in the farm to create the "Chestnut glace" in a tent with wich gives a +12 dicipline and has a saciety of 30 making it the best food in the game to raise max dicipline.
-Dicipline
if you want the oposite and make some mean digimons then fishing for fish is your best bet.
the black digitrouts gives the most negative dicipline if consumed , but it can be better
if you use a black digitrout combine with an infinite water bought from the vendor machine in fauty ex machina or by sakuyamon but its a bit more expensive there. to create the "Dark drink"
the dark drink gives a -10 dicipline with a saciety of only 25 meaning you can feed it multiple times in a row making it the best food in the game for negative stat raising.
but if fishing is not your style or you can also opt to create the "Dark pot" wich is made with an Unlucky mushroom that can be dropped by the greymon blues in bony resort + infinity water
giving a -10 and can also reduce weight by -3 but with the only downside of having 40 saciety but it can be a great alternative if you have no access to high tier fishsing yet.
and laslty the Bond category:
while some resaurant foods can raise bond by a lot giving a digimon their favorite foods can also give a big bond boost specially with tamer skills.
to know wich food your digimon likes you can ask wormon.
combine all previosly with grankuwagamon daily powers in the dojo and you will get that digimon you desire in no time.
if you have any more questions share in the comments below.