Various things including gradual inclinations toward becoming blorp-pilled and blob-pilled led to the concept of taking fatquestria, and taking things a couple steps further. There are worse things to fall to than taking fat interests and making them even bigger, I guess.

There exists a world, a reality even further beyond “Fatquestria”. In this world, all that was necessary was pushing the start date of one event back in time. 
That catalyst appears right after the banishment of Nightmare Moon. Celestia’s sorrow manifested in compulsive overeating, and the initial reaction to her gained weight caused her to seek even further comfort. Before long, Celestia’s ever-increasing obesity came to be seen as a sign of wealth and royalty, and thus was celebrated. Royalty and wealthy ponies alike began following their princess’s lead. Health issues began forming among those castes, and the princess herself had a few scares. In addition to beginning to recruit protégés at an earlier time to help deal with issues arising in the empire, Celestia compelled by royal decree a meeting of all alchemists, doctors, and well-studied unicorns to develop a solution for the obesity crisis that had begun claiming the lives of the upper caste’s portlier members.
	By this point, Celestia had gained nearly 800 pounds, and couldn’t give up her addiction to ingesting cake. Instead of finding a way to restore the old weight and health of the empire and revert standards to the old ways, Celestia demanded the council she assembled to, instead, determine a manner in which the current trends could continue without ill effects. In modern times, their creations are known by corporate brand names “Quik-gro” and “Gro-assist”. The council, excluding those who refused and were sent home without compensation for their time and travel, developed a combination of alchemy and spellcraft, working closely with doctors to find how best to apply effects to ponies, to remove nearly all negative side effects caused by excess size and weight. Part of this effort had also created methods in which to enchant foods and plant seeds with these effects, allowing the health effects to apply without the need to purchase and use scrolls and potions, opening the capabilities up to non-magical pony races. Further developments led to increased crop size, growth speed, and eventually: caloric content.
	For hundreds of years, in part due to concerns toward the working classes growing too fat to adequately perform labor and soldiers being unable to provide adequate defense and offense, this technology was kept somewhat secret, available only to those in the royal and wealthy castes. This led to some internal quarrels: at multiple points, uprisings appeared and had to be put down with force, from the poorer, lower class citizenry getting fed up with inequities incurred between the slovenly leadership and overworked laborers.
	Celestia went through protégés in a relatively quick manner. As the protégé proved successful and gained Celstia’s favor, she would treat them to more and more of the royal caste’s benefits and secrets, until eventually the protégé had grown too fat to perform the expected duties, and had to be replaced. Further fueling some of the uprisings, and generating some disdain in the upper castes, the protégés that had outgrown their duty were given lodging in the city and a high salary simply for having formerly been Celestia’s right-hoof mare or stallion. They held high status and no responsibilities beyond the occasional compulsory meeting with the princess, which was a thinly veiled invitation to a festive and very excessive dinner party. 
	As more centuries passed, the average weight of the upper castes, the protégés, and the princess herself climbed further upwards. It became rarer to find a citizen of these castes of any age whose belly wasn’t at least brushing the ground at all times, on an empty stomach no less. Even Celestia, who had clearly been obtaining more heft in her rear than anywhere else, had begun feeling the cold floor on her titanic tummy. Celestia called a new council of alchemists, engineers, and studied unicorns together to discern viable mobility assistance devices for those of excessive size. 
Shortly thereafter, things had started transitioning to a state more familiar with “Fatquestria’s” norms, in this “Fatterquestria” realm. The technology developed long before started having a public face in the form of a corporation and marketing-friendly named products, though clientele were still by majority the upper castes alone. During the latest round of magic school elementary ceremonies, Celestia was able to find her most recent protégé in the form of a certain purple unicorn filly who managed to hatch a dormant dragon egg with a magical spell, and had regarded Celestia’s corpulent form as the sun itself during a fateful Summer Sun Celebration. 
Things had progressed with this protégé faster than the others: Twilight had grown quite fat before being sent on her first mission, owing to the increasingly stable and safe times and Celestia taking her newest, and most promising, princess candidate yet considerably more than she had any priors. Upon realizing her sister would be making a return, she sent Twilight to Ponyville under false pretenses of preparing the festival. Much of the following events remained identical to many variants of “Fatquestria”, and to the “standard” Equestria. Twilight’s heftier form drew equal amounts of hushed scorn and respect from the ponies she met along the way, being immediately recognized as a high status royal due to her excessive poundage. She was, of course, much more accepting of the Apple family’s lunch offering, and tried apologizing profusely for unintentionally eating every morsel of food that was available before suspiciously-blushing and stammering Applejack assured her there would be more than plenty of food left for the celebration. 
The reformation of Nightmare Moon and vanquishing of various successive threats cemented Equestria as an even safer, more stable land that no longer needed many of its old restrictions and concerns. Despite Twilight continuing to gain weight, and her form and eating habits rubbing off on her friends, no issues impacted the completion of the various tasks that came forth. That is, excepting events that required dresses or similar formal clothing. 
Eventually, Twilight too had reached the point where prior protégés had retired. However, she persevered despite her belly rubbing against the ground, and solved a spell Starswirl could not complete a millennium ago, and ascended to Alicornhood. The slowly increasing height and body size saved her from retirement. Celestia, now weighing over a ton, personally oversaw the coronation ceremony, and dubbed Twilight as an official princess, putting into place a future plan to retire from ruling the Kingdom and its “independent” territories (e.g. The Crystal Empire, ruled by a protégé that otherwise would have been used for her retirement plan, the brother of the newly crowned princess, and their daughter) and living out the rest of her life merely enjoying all the perks of her status with none of the responsibilities. 
During this time, Luna had taken to her sister’s antics and had quickly grown nearly as large as her. She met with a lot of the citizenry in their dreams, and learned there was a desire to open up the excessiveness of the upper castes to the rest of the population, now that threats and unrest had all but disappeared from the lands. After careful deliberation, it was decided that rollout of Quik-Gro and Gro-Assist would become universal, priced to be affordable by all, and that all were free to relax and indulge. Many would argue this decree had still come too early, as there was inadequate planning regarding how to handle the laborers outgrowing their work and the entire military becoming little more than a pitiful force who could fight off an army of cakes, but little more. 
With nothing short of great luck, no negative consequences were born from the premature opening of Panblorpa’s Box. Independently, without need for formal councils, engineers and spellcrafters devised automation to perform manual labor duties, and some forms of mobility assistance were given public accessibility for those who truly needed it. The rare few threats that appeared were tamed by culinary hedonism. The greatest challenges were the need to remodel furniture, buildings, and sometimes even entire cities to accommodate for a nearly-exclusively enormous population. Furniture and buildings are largely self-explanatory: larger doorways, larger rooms, larger seats and beds, reinforcements on floors, furniture, and especially upper level floors to prevent breakage and falling through. More urbanized cities like Manehattan required excessive levels of building remodeling as well as a total overhaul of any and all elevator to make the sometimes hundreds of floors tall buildings viable. Canterlot required the addition of supports, fearing the city may dislodge itself from the mountain. 
The average, normal citizen now holds, with variance accounting for body shape and sex, enough excess weight to leave mere inches of ground clearance beneath the crest of their bellies. To be considered “chubby” or “overweight” requires gaining enough weight to lower that clearance to centimeters or less. To be considered “fat” requires one’s belly to rest on the floor at all times, and it must be more than just the point of largest diameter doing so. To be considered “obese” involves the belly not only reaching the ground, but also spreading out between the legs and increasingly making mobility more difficult. One is not considered “excessively obese” until mobility is lost, either due to being too heavy to stand or walk, or due to being too fat to reach all four hooves to the ground.  The rarest form is known as “morbidly obese”, and all but requires being a citizen of Foaledo, the only settlement in Equestria where gluttony is engaged in to such excess that health issues that had been solved for nearly a millennium return to existence, where immobility is achieved during foalhood, and where from the moment one wakes up to the moment one falls asleep, excessively high calorie food is being ingested and digested. 
Similar to Foaledo, ponies all over Equestria typically achieve their body size during foalhood. Size and status during foalhood can vary due to interactions between appetite, food intake, and the fact the body is still growing to its full size. Once a pony reaches adulthood, they no longer have this variance. They will either maintain the same weight grouping, or grow into a larger one. There is no turning back, losing weight. The composition of the food, stomach capacity, and learned appetite make such a feat impossible. Even one who has fallen ill will come out of it in equilibrium or with even more weight being added.
There remain trends in races, excluding once again the city of Foaledo, where anypony will likely eat themselves to death.
•	Alicorns: Exclusively obese or larger
•	Unicorns: Very commonly obese or larger, less commonly chubby, rarely “normal”
•	Earth ponies: Very commonly fat or larger, rarely chubby
•	Pegasi: Commonly fat or smaller, rarely obese, very rarely excessively obese
•	Bat ponies: Commonly fat or smaller, less commonly obese, rarely excessively obese
There are also trends relevant to the current residence of the pony.
•	Foaledo: Nearly exclusive home to the morbidly obese, smaller sizes seen only in the recently born and new arrivals from other cities
•	Canterlot: Citizens average 200 pounds heavier than elsewhere, unicorns have a far greater chance of becoming excessively obese, weight classes below obese are rare
•	Cities (e.g. Manehattan, Baltimare): Citizens average 100 pounds heavier than elsewhere, lesser chance of any weight class below fat
•	Ponyville: Citizens average 80 pounds heavier than elsewhere, 160 pounds heavier when including Twilight and her friends
•	Smaller towns and villages: highest concentration of weight classes ranging from “normal” to chubby, higher classes are rarer