The Akimichi clan hails from Hi no Kuni and its loyalties currently lie with Konohagakure no Sato and always will. The clan is mostly known for its hijutsu which allows them to manipulate the size of their body or parts of their body.
Through out history the Akimichi have always been a clan that only desired peace in their lives. For hundred of years their motto has been to "Defend those in need, and nuture every seed." This referencing that the majority of the Akimichi clan are simply civilians who tend a multitude of farms across the entirety of Hi no Kuni with only a small percentage of clan members undergoing shinobi training.
This method formed a tradition of sorts that the Akimichi clan would always just have a small amount of their clan members become shinobi, even after joining the shinobi village. While their clan could potentially be one of the most powerful if they trained every clan member in the shinobi arts, they prefer to believe that the clan members tending the farms and ranches are doing a greater good than the shinobi clan members ever will. While not all the members of the clan follow this idealogy, the majority of them respect it at the very least.
As said previously, the Akimichi started and remain a collection of farmers and ranchers for the most part. Originally the clan started with a single large farm near a mountain range, with the father and first son having learned the shinobi arts in order to help defend their land from bandits and the occassional roaming shinobi.
In that time the two shinobi played with a single idea, wondering why they couldn't truly affect their size through the transformation technique. Over many years, eventually the son succeeded where the father could not, developing a method in which he was able to change the size of his body while maintaining his abilities and not returning to his normal state from being hit with an attack.
Over an additional couple generations this ability was further developed, not just to defend their lands, but more importantly to help them cultivate their lands. With training the members of the Akimichi clan were able to user their bare hands to plow their fields, clear trees and pick up and heard even the largest of their animals with ease.
By and large the Akimichi followed this pattern of cultivating and expanding their lands, selling food to those who needed it and protecting their lands and families when they had to. As this continued, rather than buy out other farmers, the Akimichi offered to take them into their family where the other farmers and ranchers could develop the same abilities and reap the rewards.
This cycle continued for some time, until some of these farmers began to turn and use their abilities to harass villages and travelers. While the other Akimichi quickly put these incidents down themselves, they became much more protective and secretive of their techniques, wanting to ensure that only people who were truly worthy of utilizing it learned it.
Even as the various clan wars raged around them, the Akimichi were largely left alone. There abilities made it a fairly simple matter for them to destroy large groups of opponents and while it is likely that many members of other clans like the Senju or Uchiha could destroy the Akimichi, the cost to them would be irrepairable if they truly angered the giants of Hi no Kuni.
Eventually, it was when the Uchiha and Senju were working with the Daimyo of Hi no Kuni to set up a shinobi village that the Akimichi were approached. The coallition of shinobi clans wanted the Akimichi to join the village, as their farms could always ensure the village was properly fed and naturally their abilities could prove to level the playing field against any other coalition of clans that rose to try and threaten their boarders.
At the time the Akimichi were hesitant, but after conversing they decided that their methods would not be effective enough in a time where entire villages filled with shinobi were rising. So, to help ensure peace through out their homeland the clan pledged its allegiance to the newly formed village, donating the very first farm held by the original Akimichi clan to serve as the building ground for the village that would come to be known as Konohagakure no Sato.
In the time since the founding of the village the Akimichi have done their best to stick to their roots. They have several families train in the shinobi arts to help support the defense of Hi no Kuni and Konohagakure no Sato, but by and large the majority of the clan members tend to the multitudes of farms and ranches, calling upon members of the shinobi families or even the shinobi of Konoha when they need help with particularly difficult tasks.
Lastly it should be noted that since joining the village, the Akimichi have always been steadfast in their loyalty and Konoha shinobi are almost always welcomed at any home owned by an Akimichi clan member where they are generally given room and board if asked in exchange for just helping out with a few chores.
Overall the Akimichi clan is rather plain when it comes to structure. Within the clan, the Akimichi maintain a main family which almost always undergo shinobi training, several shinobi families and then the remaining clan members all are from the civilian families. Overall it is the head of the main family who makes decisions for the entirety of the clan, but often he is advised by a member from one of the other shinobi families and a member from one of the civilian families.
Hijutsu: Taishū Sōsa - [Hijutsu: Mass Manipulation]
For hundreds of years the Akimichi have been developing the ability to manipulate their mass at will. This allows the clan member to add to their mass and in turn expand the size of their body. Naturally this provides a signifigant boost to their combat capability as it grants the user much more weight to their blows and effectively raises their strength and speed, by making everything around them smaller in comparison.
Because they are becoming much larger, this in turn means their muscles are becoming larger. While proportionally to themselves their strength is unchanged, by changing their proportion to objects around them, an Akimichi clan member is able to treat a massive bolder like a pebble, lifting it and tossing it with ease.
It is largely because of this titanic strength that the Akimichi were first approached to join Konohagakure no Sato, as their abilities allow them to act like machines of death on the battlefield, with a single jounin level Akimichi being able to hold off dozens or even many more shinobi on their own.
Additionally while it is very rarely used, the Akimichi also are capable of utilizing jutsu that reduce their mass and thus their size. While they are not particularly useful for combat scenarios and thus are fairly rare to be used; their usefullness in espionage missions is far greater and should not be underestimated.