"I started designing these yearlong challenges, and I knew I wanted to do an eating challenge because eating is a really large challenge that many people are interested in and want to take on," said Existence in a phone interview.

For an entire year, Beautiful Existence (yes, that's her name) ate all of her meals exclusively at the company's brands and documented it .

One Seattle-area woman just gave the phrase " Starbucks junkie" a whole new meaning.

Beginning Jan. 1, 2013, Existence dined only on items from Starbucks, Roy Street Coffee & Tea, Teavana, Tazo Tea, the Starbucks corporate cafeteria and Evolution Fresh. Her interest in the company was piqued by her sister's nearly eight-year tenure as a Starbucks barista.

"They've treated her really well. They were on my radar as a company I'd want to explore and find out more about," said the 40-year-old part-time undergraduate student at Bellevue University and former small-business owner.

The challenge was the latest in Existence's yearly pacts centered on brands. In prior years, she's shopped exclusively at Goodwill and tested out advice from Parents Magazine. This year, she's planning to learn more about outdoor equipment retailer REI by trying more than 80 recreational sports.

Existence estimates she spent more than $7,000 on Starbucks products last year. To put this in perspective, the average female 19 to 50 years old spends about $252.50 a month on food eaten at home as part of a moderate-cost budget, or about $3,030 per year, according to the Department of Agriculture.

Although Existence tried to stick to a budget, her purchases added up to more than she anticipated spending.

"I thought it would be over $5,000—but $6,000 at the most. It was definitely a bit more than I thought," she said.

Although Existence's challenge is somewhat reminiscent of Jared Fogle's vow to eat Subway regularly to lose weight, she said she has not received any special consideration from Starbucks.

"They've been incredibly kind and generous, but they never paid me or gave me discounts," she said.