An anonymous commissioner commissioned this short story by Kassaz, part of this anthology:
https://www.fimfiction.net/story/574592/2/short-stories-about-fizzle-before-she-pops/sweets-and-snacks-tasty-and-tempting

Sweets and Snacks, Tasty and Tempting

Apples, Tempest Shadow was in the Ponyville marketplace for apples, and nothing else. She had gained plenty of weight while her body prepared her son for the world, and wanted to make sure her son were most of that weight. While she waddled between the stalls, she silently noticed that her belly wasn’t the only part of her body that had grown in the last weeks, and chose to ignore the extra padding on her rear.

She took a deep breath, and immediately regretted it when the sweet smells of cinnamon and sugar hit her in full force. The marketplace had fresh fruits and vegetables, alongside so many delightful treats made from them that beckoned to her. Every single stall with produce had something made from it as well—she knew it only made good sense to sell what ponies would buy—and she found it so tempting to relax for another night, to buy something for dinner instead. Tempest could produce her own breads and pastries at home, but she lacked the lifetime of cooking it seemed everypony in the village had, and she reminded herself that their prices weren’t even bad.

She shook her head, and stopped ignoring her butt, a butt that would only get bigger if she ate pastries and pasta every night. Tempest could smell something delectable from Sugarcube Corner, it smelled like their fresh chocolate donuts, but couldn’t see why. She’d specifically avoided Sugarcube Corner on her way to the marketplace.

“Hey, Fizzlepop! How ya doin’?” Tempest saw Pinkie Pie bouncing her way, somehow balancing a box on her back without any trouble. Tempest started to speak when Pinkie Pie interrupted her. “Say, would you like a donut? I just made ’em fresh, and they’re so good!”

Pinkie bounced the box of donuts high in the air and sat on her rump before catching and opening it. Tempest licked her lips without realizing it. “Thank you, but I’m fine. I wouldn’t want to take any of your donuts.”

“Oh, they’re not mine. I’m a deliverymare right now, kind of like you’ll be in a few months.” Pinkie wiggled her eyebrows and laughed. Tempest tried to stop herself from joining in. “I just always add a few things to every order so I have a snack.” Pinkie Pie stuck her tongue into a donut to grab it and swallowed it whole before closing the box. “See ya!”

“I wish I had your metabolism, Pinkie Pie.” Tempest waited until she was out of earshot.

She could see Applejack’s stall sandwiched between two booths in the distance and tried to ignore the rest of the market as she waddled over. It occurred to her she should buy a pair of blinkers. Applejack noticed her and waved. “Howdy, Tempest. What can I do for ya?”

Tempest sighed and smiled in relief. “Hello, Applejack. I’d like to buy some apples, please.”

“Well, I can do that for you. What kind of apples? We’ve got a new bucket of honeycrisp right next to ya.” Tempest looked down and started grabbing some to set on the counter. “We’ve also got candied apples, and caramel apples, if I may interest you in one, or both.” Tempest finished setting her third and last apple on the counter just as Applejack had nudged those confections towards her. She gulped and couldn’t look away; her stomach growled. She could nearly taste them, and it would be so easy to eat one right there.

Tempest managed to pull her head back. “No, thank you, I’m trying to avoid sweets today. These are for a salad.”

“Oh, well don’t let me talk you into buying more apples, unless you let me.” Applejack laughed, and Tempest joined her.

It was easy to pay with somepony around to take the bits from her saddlebag, and to nudge the apples inside. Soon enough, Tempest was away from temptation, and ready to relax. Her saddlebags balanced on her belly more than they hung from her side, making them difficult to slide off, but she had long ago found a nice solution to her problem: A wooden hook was arranged to allow her to duck her head and walk underneath it, catching the saddlebags until she was ready to use them again. She smiled, until her saddlebags caught on her rear for just a moment, nothing a wiggle wouldn’t fix. She sighed, grabbed an apple in her mouth, and walked to her kitchen.

-

Tempest was slicing an apple for a fresh salad with some crumbled cheese, and a basic dressing in a glass bottle also sat on her table; rather than a knife, she used what the other tribes had for slicing fruit, a device like a press that fit the fruit inside and which could be pressed down with one hoof. She nearly frowned for a moment about her inability to delicately use a knife for the task, but instead smiled when she thought about her son using his magic to help her once he was a little colt running around the house and cooking with her.

She had discarded the core and put the slices on her plate when she heard a knocking at her front door. She finished arranging her plate and left the dressing for later. After waddling over and opening the door, she looked down to see a young filly with a yellow coat, a blue mane, and a wagon behind her holding small bags that appeared to be made from wax paper. “Hello miss, may I interest you in some filly scout cookies? I’m helping raise bits for a camping trip!”

Tempest smiled at the filly. She very nearly started to tell the filly about her diet, but the mere thought of turning the filly’s smile into a frown wounded her, and she chose to feign interest by leaning closer to the wagon. “Well, what kinds of cookies do you have, little filly?”

Tempest’s smile grew as she watched the filly excitedly turn towards her wagon and start rifling through the bags. “I have a mint, a lemon grass, a daisy, and blueberry! We made them fresh today too!”

Tempest remembered eating blueberry cookies once, long ago, with her family, and found it difficult to ignore the blue cookies she saw through the paper. She seemed to recall blueberry being one of her favourite flavours. She looked back to the filly, waiting patiently for her decision. “I’d like a bag of the blueberry cookies, please.”

Tempest had to walk to her bit bag to pay the filly, who then happily left her alone to munch on her salad and stare at the bag the entire time. Once she was finished, she cleaned up after herself, and wasn’t quite certain what to do with the cookies. Her stomach rumbled despite the salad she’d just crammed into it. She swallowed. “I’m sure one cookie won’t hurt.”

-

A jab underneath her navel brought Tempest back to cognizance. She yawned, and noticed her mouth tasted awfully sweet; something was stuck to her muzzle, something cold, which she recognized as ice cream once her tongue swept it away. Another kick had her turning her head towards her son, and she saw discarded chocolate wrappers sitting on her bed next to the tub of ice cream. She couldn’t quite remember how she ended up in bed with all of these treats, but this seemed too extreme to be one of Pinkie Pie’s pranks.

Another kick had her sighing before she rolled over onto her back to get a better look at him. She didn’t like the way her belly jiggled even after she’d stopped moving. She rested her hoof where she could tell he was going to kick next. “I’m blaming you for this one, little stallion. Enjoy your sugar rush.” She decided to try to sleep and clean up later.