Celestia's Weight Gain Experiment

“You can’t be serious.”

“Ha! That’s exactly what Twilight said.”

Princess Celestia and Princess Luna walked side-by-side in the cavernous hallways of Canterlot Castle. The incredulous expression and tone of the stary-maned mare did its best to redirect her sister’s course but was obviously failing.

“Do you not find it uncouth to blimp up like a party balloon for all of Equestria to see? For all of our allies to see?”

“Oh sister, it would just be a bit of harmless fun. And a benefit to Twilight on top of that. Her spell could be quite revolutionary if deemed safe. The whole point is for me to recognize when enough is enough! And you know, there were eras in Equestrian history where fat was a signifier of power, wealth, and prestige.”

She looked down at her little sister (with an emphasis on little). Princess Celestia, while thin, had elegant curves to her back and flanks, ending with a smooth, impressively proportioned butt which shared a spotlight with her dazzling sunshine cutie marks. Luna, on the other hoof, was mostly just skinny – thin legs, thin torso, tiny butt. Her crescent moon cutie mark had very little space to work with. It was as if the literal difference in size between the sun and moon were analogous to the two mares responsible for their stewardship.

“Besides, if I ended up getting a bit chubby, you could probably get away with a few extra pounds. Relatively speaking, of course.”

“I beg your pardon?”

“It really is not the end of the world to gain some weight! Some mares and stallions even like that in a pony.”

Luna halted in her tracks, her look of confusion changing to one of shock. Her sister was seriously suggesting that she put on weight as well! Celestia paused and tapped a hoof to her chin while continuing.

“Er, at least one mare I know of. That Rainbow Dash may be a bit unorthodox in her tastes now, but styles and norms are always changing. It certainly wouldn’t be the first time royalty set a ‘trend’ like this. It’s like…the opposite of a corset!”

Celestia smirked and bumped Luna’s bony cutie mark with a hoof.

“Ew! Goodness gracious, no! I am not going to plump myself up just for the sake of keeping up with your…’fashion choice’ (?). I know that trying new things is the best way to deal with immortality – perhaps even better than you do. There is no shortage of fantasies in the dream realm. But this? It just seems…base – like the simplest thing a lazy pony with too much food could ever do. I do not understand what could be so great about it. I won’t stop you. I won’t join you. But…”

Luna paused to search for the appropriate conditionality to set for this bizarre lifestyle change in her sister.

“I am going to make fun of you the whole time.”

Celestia chuckled into her hoof.

“Sounds fair to me. I’m making a batch of pancakes, by the way. If you want some, feel free to join me for breakfast.”

“Oh no, you won’t get me that easily.”

Celestia returned to her office quite pleased with having gained the blessing of her sister, if a bit begrudgingly. Planting the seeds of temptation was just icing on the cake at that point. She briefly imagined what Luna would look like if she gained even a quarter of her body weight in fat. Rail thin torso replaced by happy, healthy barrel. Sharp, bony butt turned thick and bouncing with every step. It would be quite the sight, indeed. She needed some icing on her cake.

While Princess Celestia was honest with herself and with her sibling about the potential thrill of cutting loose and gaining some curves, she still did not want to disappoint her student who was very much expecting a concrete result to the experiment. Celestia prepared a graph and posted it on a large bulletin board in her office. She could track her starting weight and even take photos documenting her progression. All the while, she prepared a personal journal to log observations about herself, her attitude towards the gain, and the reactions of other ponies.

Flipping through a personal scrapbook, Celestia searched for a suitable “before” photo. That’s when she noticed it.

“Let’s see here, this one is from a ceremony before Luna came back. Here’s one from visiting Twilight in Ponyville. This was a few years ago and…huh?”

Celestia’s eyes narrowed as she floated the three polaroids in front of her.

“That’s odd. I could almost swear my butt looks…bigger. Over time, too. Did I- have I been gaining weight without realizing it?”

She quickly levitated a full-length mirror over to herself from across the room. She pivoted in place and inspected her flanks before returning her gaze back to the photographs. In each image, the difference was subtle, but the trend was clear: each time, her butt had widened, her legs had thickened, and her sun’s circumference had expanded – as if it were literally outshining the original.

“Goodness. That’s not. I didn’t…”

Her gaze returned to the mirror.

“I mean…pfft…that’s actually not so bad.”

Celestia knew how to charm a potential suitor. She struck a more seductive pose by bending her forelegs, stretching her hind legs in front of the mirror, and raising her tail to give a better view. Her cheeks blushed and she grinned foolishly, her expression stuck somewhere between embarrassed and flattered. Her lovely rear looked just a bit bigger than the most recent image.

“Looks like I made an ‘after’ photo without even trying.”

She opened a drawer to reveal a camera, levitated it next to herself, found an angle that was juuuuust complimentary enough to her exquisite flanks, and snapped a photo. She stuck a pin in all four photos, keeping chronological order. With a nearby pen, she marked a diagonal line, rising ever so slightly upwards from left to right on the graph. She dated the entries accordingly but couldn’t quite specify the difference in weight so far. She concluded ‘now’ was going to have to be the baseline. Next came the journal.

“Preliminary thoughts: I may look good with a few extra pounds on me. My butt has evidently been growing for years without me paying it much mind, and it is rather complimentary now that I can see the difference. It’s fuller. Somehow…healthier. Seems a few years of delegating long journeys to Twilight and her friends has led to more sedentary time spent at the castle (with predictable results). I suppose ponies were either too polite to comment on my growth, or it has been so gradual they hadn’t noticed either. I wonder if a few more pounds will change that. I wonder how long it takes before shock overwhelms etiquette and ponies start gossiping. I wonder if it’ll still look enticing if it’s even bigger. For certain: I will quit when it feels like too much. Easy as pie. Which, speaking of…”

+0 pounds since last measurement; +0 pounds total

Everything was set. The plan was clear. And the elegant Alicorn’s tummy was certainly rumbling. So why, Celestia wondered, did her heartbeat feel so quick and her face feel so warm?

“…time to get started. For real this time.”