Its probably a bad move.
Taking a good look at your main strategy, what you're doing is not too dissimilar to Napoleon's approach to conquer Russia during his empire (you know? The one military move that was an absolute disaster and essentially doomed his plans as an emperor to destroy England financially and conquer Europe?), but with a more cannibalistic approach. Basically what this does is that you do have proper resources on you, but you also rely a fair amount on there being resources on the regions you conquer, with your own provisions still existing and being delivered. The biggest pro of this move is that, thanks to not being as encumbered by the extra weight of a lot of provisions, your army can move faster and cover more ground, meaning the enemy has less time until you arrive.
This link explains fairly well the problem.
But to sum it up a fair bit, here are the main pros and cons of relying a fair bit on resources from the conquered regions:
Main Pro: the smaller amount of heavy provisions being carried around makes the troops capable of moving faster, meaning less time for the enemy to prepare for your arrival. Napoleon himself planned for the war against Russia to be quick, which likely motivated his choice of this strategy involving more mobile troops.
Main Con: to depend on your enemy's resources is a huge gamble, because if there are no resources for you to take, you won't last.
The problem with Napoleon's advances was that not only was he in a territory with a fairly unforgiving climate and fewer number of large crops to take, he was fighting enemies willing to sacrifice it all to destroy him.
Your situation has similar problems, if not greater ones.
Firstly, Humans are a potentially viable source of food, especially if you back it up with other nutrients to ensure you're getting all the nutrients and vitamins you need, so the nutritional problem is likely the least of your problems with this strategy.
By eating the civilians instead of just being normal and stealing the food they would eat, you put your soldiers at a risk of contracting prion-related diseases. Make sure not to eat the brains. You also risk causing even more severe psychological impact on your troops, because humans as social animals are naturally hardwired to be against cannibalism (normally a person will start to consider cannibalism under a rather extreme state of starvation, at which point their brains have already shut off natural inhibitors against things they also wouldn't normally eat. The body is so starved the brain starts to consider any food as fair game).
The main problem I see with this however is that while you might be hardwired against eating your buddy, your buddy is hardwired to be against eating you and to be against letting himself be eaten, and that's where it falls apart.
Like Sun Tzu in his book "The art of war" already said: "When you surround an army, leave an outlet free. Do not press a desperate foe too hard.". The reason for this is that if an enemy sees a way out, it's very likely for them to first try to flee to safety. However if they're completely cornered with no apparent hope of being spared, then they'll naturally go from flight strategy to the fight strategy. They're cornered, they're hopeless and they have nearly nothing to loose, so they might as well give their everything. The intense stress of being in a deadly situation also makes them more prone to release natural limiters and make use of their "hysterical strength", which while not necessarily as absurd as what some tall tales might tell you, isn't something to brush over, especially when that strength is being directed towards killing you.
As for the fear factor compelling submission, it just has little chance of working for long. Sure, you might tell everyone that you won't kill and eat them if they surrender, but anyone with a brain and the knowledge that you don't carry around a lot of food on you can tell that you're not only unwilling to keep your word, you're incapable of doing so. That means there's a higher chance that the peasants you plan to snack on will be naturally desperate even before you arrive, which makes them more willing to take desperate measures, such as abandoning and burning down their villages. If you can't find a village with any provisions to use or food to feed your troops with, you'll have to take your hungry soldiers to the next one. That is a problem if every village is willing to do that, because if you can't feed your troops, you become much more vulnerable, you also have the problem of now having an army of cannibals alone and starving with nothing but one another around, all coming ever so close to the necessary psychological conditions to begin considering an ally as a snack. Basically, with a strategy such as yours, an enemy willing to have losses in order to crush you can force you to retreat by not engaging with you at all,because if you retreat they'll gain time, and if you don't you'll eventually have to retreat, but this time weaker and a more vulnerable against those you were invading.
Essentially, it's a gamble with a high risk and varying reward. Sure, you're faster, but you become like a natural predator, dependent on finding proper prey, the absence of which will make you grow weaker and make you easier to target as time goes by. Put your troops in an attempt to conquer Russia and you'll probably end as the new Napoleon, but one with a thing for human meat.