How can you have a 28 hour feeding cycle? The article states that they alternated a 20 hour fast with a 28 hour feeding cycle. Doesn't the 28 hour feeding cycle

How can you have a 28 hour feeding cycle? The article states that they alternated a 20 hour fast with a 28 hour feeding cycle. Doesn't the 28 hour feeding cycle also include a fast since the fruit flies will sleep at night?