Rospinner, I'm a little confused by your description. Fasting just means stopping. What you stop and for how long depends on what you choose. Althought fasting is mostly associated with eating.
Not eating immediately before (30 minutes) doing meditations, helps to quiet the body and makes it easier to go deeply into a meditations. It is not a required condition for a deep meditations.
Not eating after a meditations allows the energy flows you have established during meditation to continue less disturbed, and so to continue longer and stronger.
An extended fast (a day or more) of any degree allows the body to become quiet / still, which facilitates deep meditation. Whether you do a three apple fast, a juice fast, a water or a dry fast. It is different degrees of how you are quieting your body. That said, I'm not telling people to jump into a fast without due dilegence.
That fasting stuff said. Don't pass on a 15 minute of small universe at coffee break, just you had a glass of water (or an apple or donut) just a minute ago. Maybe it is not the best practice, but any time spent in SFQ is Good for you. Maybe not best, but good, is how you should treat the whenever you can opportunities.
As a personal note, I think you'll be surprised at how much you get out of that 15 minutes, especially if you do it every day at the same time. Make it the 15 minute morning break for you, not the 15 minute coffee break that you don't really need. 
You are perfection.
Iam2 
Th