Some inmates at Campsfield House immigration removal centre in Oxfordshire are continuing to refuse meals.
Detainees said the demonstration, which began on Monday, was due to people being detained for long periods.
About 80 detainees decided not to take food on Tuesday evening, the UK Border Agency said.
A statement claiming to be from inmates said more than 140 people continued to refuse meals.
The UK Border Agency said inmates had access to food from vending machines and that there was also an on-site shop.
A statement from the inmates said some people had been detained for more than three years at immigration removal centres across the country with "no prospect of removal or any evidence of future release".
They added that on-site immigration had "hidden away and refused to engage in any communication or dialogue".
A spokesperson for the UK Border Agency said staff were monitoring the situation closely and were listening to the detainees' concerns.
He said: "UK Border Agency staff on site hold daily surgeries with detainees to discuss their cases and serve paperwork on behalf of case working offices.
"Throughout the protest, UK Border Agency staff have continued to conduct these surgeries."