Julie Hamilton falsified records to disguise her cruelty but was caught by a hidden camera.
She was tasked with looking after the partially-sighted woman at the victim's home in Willenhall, but the 54-year-old embarked on a campaign of ill treatment that lasted weeks and involved holding back food and drink.
At other times she force-fed her or took food from cupboards and ate it herself.
On one occasion food for the victim was poured down the sink. Yesterday, Hamilton, who sat with her head bowed and sobbed throughout proceedings at Wolverhampton Crown Court, was jailed after she admitted wilful neglect of a person lacking capacity.
The court heard the victim suffered from dementia and incontinence and, following a stroke, required constant care. She received up to seven visits a day from staff at Complete Care, in Willenhall.
Mr Kevin Jones, prosecuting, said a covert camera was set up in her home in April last year after another member of staff became concerned about her deteriorating health.The footage revealed a 'substandard' level of care being offered by Hamilton.
"Food was given to her forcefully," he said. "At times it was given very quickly, which didn't give her time to digest or swallow food."
Mr Jones said that on one occasion Hamilton, of Hunts Lane, Short Heath, Willenhall, repeatedly ordered her victim to swallow food. "When she refused, Hamilton said 'Well you'll go without' and turned on her heels and left," he added.
The footage also showed Hamilton taking food from the victim's cupboards and eating it herself. She was also seen to open a tin of food and pour its contents down the sink.
Mr Jones said that Hamilton began to 'falsify and enhance' records to pretend that food and drink had been given to the victim.
Mr Patrick Currie, defending, said Hamilton had been a care worker for 23 years and had a previously unblemished record.
He said she suffered from a major depressive disorder and had behaved 'totally out of character'. "As a result of this case she has suffered enormously," he added. "She is utterly disgusted with herself."
Hamilton was jailed for two months. Judge John Warner said the justice system had a duty to protect those that cannot protect themselves.