A stay-at-home mom’s candid math breakdown about her daily diet soda habit has gone viral after she revealed she was spending more than $600 a month on fountain drinks alone.
Hilary McKay (@hiliary.mckay) told Instagram followers she drank up to eight 44-ounce Diet Pepsis a day, often more, before the cost finally pushed her to quit cold turkey.
After documenting her decision publicly, McKay later shared an unexpected update from her doctor that added a new twist to the viral confession.
The math behind a $600-a-month soda habit
In an Instagram Reel that went viral with more than 5 million views, McKay walked viewers through her routine. She explained that she typically bought eight 44-ounce fountain sodas a day. However, she admitted that on most days, the number climbed higher.

"So these cost $2.35 a pop," she said. Then she broke down the totals, step by step, until she landed at $611 per month. Because she typically bought eight sodas a day, she said that meant that she consumed 240 giant cups a month. Then she converted ounces into two-liter bottles. "That would equate to 156 two-liters of soda a month," she said, shocked at herself.
Although the math already looked rough, McKay added a final aside. She joked she probably consumed "enough aspartame that could knock out a lab rat or two a month." However, McKay noted, she hadn’t even touched the health side of drinking that much soda every day yet.
She realized her ‘fountain soda addiction’ was costing her $600 a month. Makes you wonder how many people don’t realize how much they’re spending on coffee, soda, and sugary drinks pic.twitter.com/VdBvztgpBg
— Financial Dystopia (@financedystop) January 27, 2026
Two days later, she followed up with a Q&A after her comments section had flooded in with questions and jokes. "I’m overwhelmed in the best way," she wrote in the caption.
In the video, she clarified that she drank Diet Pepsi from a gas station. Then she explained the logistics. She grabbed several sodas while driving her kids to preschool, and later, her husband brought home more.
"Yes, I am concerned with the health aspect," she said. However, she admitted the cost finally pushed her to act. "The $600 a month was really like my holy crap moment."
@hiliary.mckay I did the math and realized I've been spending over $600 dollars every single month on fountain soda. I'm still tired. Still overwhelmed. Still burnt out. But I'm choosing change. One habit at a time. If you are in your reset era too, come grow with me. Or just follow along to watch this train wreck unfold??.#growwithme #caffeineaddiction #sahmlife #smallchanges #healthjourney
♬ original sound - Hiliary.McKay
Her doctor delivered an unexpected update
McKay did eventually take things further and booked lab work to check if she had done any lasting damage to her body. She even recorded a phone call with her doctor, which took an unexpected turn: the doctor told her all her lab results came back normal.
While this was surprising and good news, it didn't change her plans.
The SAHM quit drinking soda cold turkey after what she called a "decades-long" addiction. Instead, she leaned on her husband as a "buddy" to not suggest she grab a soda and stocked up on sparkling water and flavored drinks. She also reused the same oversized plastic cups as a way to trick her brain into sticking to the plan.
Nine days in, on Jan. 29, she said in her Instagram Story that she was still soda-free. Although the labs surprised her, she made it clear she was proud of herself and wasn’t going back.
Hilary McKay did not respond immediately to the Daily Dot’s request for comment via Instagram DM.
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