When Jemma Doran embarked on a diet, at first she was thrilled by how quickly she lost weight.
The 28-year-old, from Liverpool, banned junk food and upped her fitness regime, going from a size 22 to a size 10 within 18 months.
But as her weight continued to drop, she discovered her sudden change in appearance was due to incurable cancer, rather than any of the lifestyle changes she had been making.
She may now only have one year to live, as the tonsil cancer has spread to her lung.
Doran decided to lose weight in December 2013. At the time she was a size 22 and weighed 15 stone 5lbs.
Just one month later she had already dropped to a size 18 when she visited her GP complaining of a sore throat and pain when she swallowed.
Her doctor prescribed her antibiotics for tonsillitis and Doran thought nothing more of it.
Over the next few months, Doran continued to eat healthy food and exercise and was proud to be losing so much weight.
"The sore throat and pain would come and go and for the rest of the time I felt great. In fact I felt wonderful to be losing weight and feeling slim," she said, according to the MailOnline.
Within the next five months Doran visited her GP eight times about her sore throat, but says she was told by medical staff that it was only glandular fever.
But in July of last year, when she was a size 14, Doran was rushed to hospital in an ambulance because her neck was so swollen.
A biopsy confirmed she had tonsil cancer and weeks later, Doran was wearing size 10 clothes.
"The irony was not lost. I’d always wanted to be a size 10 and then when I got there I would have given anything to go back and never start that diet," she said.
"I believe that in my case I may have been diagnosed earlier if my weight loss had been spotted. For that reason I regret dieting and wish I had just been happy as I was."
According to Cancer Research UK, weight loss is a common symptom of many cancers. Other symptoms that may indicate mouth or tonsil cancer include a lump in the neck, bad breath, speech problems, difficulty swallowing, loose teeth and difficulty moving the jaw.
Despite rounds of chemotherapy and radiotherapy, Doran's tonsil cancer spread to her breast bone and right lung and is now at stage four.
Her family has now set up a GoFundMe page asking for donations to pay for Doran to have alternative cancer treatment in Germany or Mexico, in the hope that it will delay the further spread of the disease.
H/T: The MailOnline.