let me reiterate the rule mentioned in my prev. post that i use in loading my pack:
"the goal should be, when wearing a fully loaded pack, to minimize in all three directions the movement of our CG from our body's normal, unladen CG."
when i load my G5 and G6 packs, i place food or any other heavy items as close to the bottom AND as close to my back as possible. i use stuff sacks containing lighter gear placed rearward of the items that i'm trying to keep closer to the small of my back and lower thoracic region. generally, if i can't fit all of my heavier items below my shoulder blades, then i'll use a slightly larger pack, that way the heavier items are all low AND close - being mostly or totally in the area of the small of my back. this also means that i generally don't use the extension collar of a pack as i feel that this, even with lighter objects can affect vertically the body's laden CG - this can more readily unbalance the body laterally. with some packs these heavier items can also, if desired, be evenly distributed, down low, between the outer side pockets of some packs (e.g., G5) - though i rarely do this, preferring to also keep these heavier items closer to my lateral CG. this arrangement works for me. unless i am mistaken, i believe that a prev. poster is also recommending a somewhat similar loading configuration, but is stressing just one benefit of doing so, viz attempting to eliminate "backwards pulling"..
the basis of my personal rule is that our balance is better without a pack than with a pack. however, since we must carry a pack, how do we do this and least affect our balance and stability. this is where minimizing the deviation in ALL THREE directions (viz, laterally, longitudinally, and vertically) from our body's normal, unladen CG comes into play.
as long as you do this, however you accomplish this, i believe you have acheived (from a balance and stability standpoint) the optimal pack loading configuration. also, purely from a balance and stability standpoint, given a choice of moving my CG a certain small distance slightly further back versus the same distance slightly higher, it is, to my way of thinking, generally preferable to keep it lower rather than more forward. my reasoning is that when traversing, in particular, uneven terrain, it is, in my experience, other than toe-kicking a root or stone, easier to loose my balance laterally, than it is to loose it longitudinally. having a lower CG is also beneficial to lateral stability. this is especially true if trekking poles are not used.
if one still feels a "backwards pulling", then i think that the pack is probably NOT loaded according to my personal rule.
the "trick" referenced in another post, to my mind, neglects the lateral and vertical components of CG and especially how they come into play with the structure of the human body, particularly while walking. the "trick" is only addressing the longitudinal component of CG, and as such misses, in most situations, the most important aspects of balance and stability. however, given the clarification in that Post of L/UL packs smaller capacity, this "trick" may in actuality be exactly the way i load my packs - i'm not sure though. i'm not sure precisely how to understand it and what are the vertical limits chosen in that Post when loading gear as close to the back as possible.