Launching on August 31, Good Food HD will broadcast a HD simulcast of the channel's schedule every day on digital satellite from 5am to 11pm.
Eden HD, which will launch in early October, will run a HD simulcast of the main channel from 9am to 3am. Both channels will be available to the 2.9 million Sky+ HD subscribers.
Marking the HD channel debuts, UKTV has commissioned a raft of new content for Eden and Good Food.
Good Food controller Richard Kingsbury has ordered a total of 267 hours of content for the channel, including the UK premiere of series two of Good Chef Bad Chef.
The channel will also air Top Chef Masters, which is presented by food critic Jay Rayner, and Neven's Home Chef. It will further broadcast "high octane" new show Man v Food, which is aimed at the 16 to 34-year-old audience.
The programmes will join Good Food's existing autumn/winter lineup of Ronnie Corbett's Supper Club, series four of Anthony Bourdain: No Reservations and Jimmy's Food Factory.
Eden will add new programmes Great Rift and South Pacific to its schedule, which includes popular BBC shows such as Life, Wild China and Planet Earth.
"I'm delighted that we are able to give fans our viewers an enhanced viewing experience of Good Food and Eden," said UKTV joint acting chief executive Keith Porritt.
"Both channels have an enviable schedule which viewers can now enjoy in the stunning picture quality that HD offers - whether that is home grown commissions such as Ronnie Corbett's Supper Club or the best of the BBC's natural history programming including Wild China and Planet Earth."
Sky's director of product management Hilary Perchard added: "We are pleased to welcome UKTV's first two high definition channels to Sky's ever-expanding HD stable.
"With these new additions, Sky continues to lead the way in high definition, with Sky+ HD customers enjoying the most comprehensive selection on high-quality content available.
"Across the schedule, we offer an unrivalled selection of HD that caters to the interests and passions of millions of customers."
According to reports, Virgin Media is considering a sale of its 50% stake in UKTV, with Sky and BBC Worldwide among the leading suitors.