The Six-week Weight Gain Experiment

Chapter 1 — The Proposal

Weight: 9 st 10 lb / 61.7 kg

The modern apartment smelled faintly of calming lavender massage oil mixed with the rich, dark aroma of fresh coffee beans. Sophie stood by the sleek quartz kitchen counter, her posture naturally upright and confident. At 5 ft 8 in and 9 st 10 lb, her physique was trim and athletic. She wore her favorite high-waisted blue jeans and an off-white ribbed tank top that hugged her flat, 27-inch waist, completing her polished look with neat red-manicured nails and her recurring heart-shaped gold pendant. Her highlighted blonde hair fell in soft, wavy layers around her shoulders, framing her light blue eyes as she laughed at her boyfriend.

Dan, her boyfriend of two years and a dedicated university sports-science student, dropped his heavy backpack by the entryway. He looked less like an easygoing partner tonight and more like a clinical researcher, carrying a thick binder filled with project briefs and data charts.
"I'm telling you, Soph, it's the ultimate dissertation dataset," Dan said, pulling out a chair at the island and setting the binder down with a soft thud.

Sophie leaned against the counter, crossing her arms and raising a perfectly shaped blonde eyebrow. "You want me to do what, exactly? Let me get this straight. You want your girlfriend-who spends all day on her feet working as a spa massage therapist at the local wellness retreat-to intentionally stop exercising, throw out her normal dietary restraint, and get fat for your university project?"

Dan offered an apologetic yet eager grin. "It's a six-week observational study tracking how rapidly body composition, metabolic markers, and daily fitness change when someone completely drops all food discipline and activity. And look, I wouldn't ask you to do it for nothing." He tapped a printed sheet of financial and professional incentives.

"Oh, there's money involved now?" Sophie teased, a playful smirk touching her lips. As the slimmest and most put-together sister in her family, Sophie had spent a good deal of time playfully lording her slender figure over her older sister Hannah and younger sister Lauren. Hannah was plus-size, fuller, curvier, and famously laid-back, while Lauren was younger, chubby, cheeky, and energetic. Sophie often reminded them both of the virtues of discipline. Just last week during a family Sunday roast, when Hannah had reached for a third helping of roast potatoes, Sophie had playfully teased, "Careful, Han, you keep eating like that and you'll need a reinforced chair soon!"-a comment that had earned her a playful slap on the arm and a loud snort from their larger-than-life mum.

The idea of trading her sleek, toned shape for extra padding-and potentially matching the softer frames of her family members-felt wildly out of character, almost like a joke.

"Guaranteed participation payment of £1,000 when we wrap up the six weeks," Dan ticked off on his fingers. "Plus a £1,000 completion prize if the dataset is thorough and complete. And best of all? When it's done, our department provides a complete personal training regime and a tailored nutrition list and plan to get you right back down to your baseline weight."

Sophie looked down at her flat stomach, imagining how her collection of fitted crop-top co-ords, tailored blazers, and figure-hugging dresses would handle a sudden surge of calories. The contrast between her current body confidence and the prospect of a soft, rounder silhouette was staggering-and strangely tempting.

"And let me guess, top-secret?" Sophie asked, catching the clause in the brief.
"Strictly confidential," Dan nodded. "If outside family or friends know-especially Hannah or Lauren, given how much banter you guys exchange about weight-it could unconsciously alter your eating behaviors or add external bias to the data log."

Sophie chuckled, uncrossing her arms and stepping forward to playfully flick Dan's ear. "Well, University Boy, if I'm going to ruin my hard-earned waistline and hear no end of it from Mum, Hannah, and Lauren once they eventually find out, £2,000 and a free personal trainer sounds like a decent start. Let's see how much junk food it takes to break me."