the debate began because you were making false comments which needed to be corrected.
Fasting by definition is not just abstaining from solid food, but also from any form of liquid nutrition as well, apart from pure water.
Short-term fasting does have its benefits, but if you are reluctant to go over a week then you are really missing out on the benefits of a longer term fast.
From what I understand of your post, and the resultant magnesium deficiency that you experienced, this would only occur if your bodys food reserves were inadequate and/or of poor quality prior to starting your fast.
In essence a fast is basically feeding on internal food as opposed to receiving your nutrition from external sources, so there is really very little difference between the two, but I can understand completely your symptoms of deficiency if your pre-fast diet of some months standing, was not of a high enough quality.
It is common amongst fasters for their energy levels to drop whilst fasting, (as did my own) but then to continue with your normal working practices whilst doing so, is only asking for trouble.
The fast is essentially a period of physiological rest and where the maximum gains are only achieved by "absolute rest".....physical, sensory, and physiological.
ALL of your bodily energies are needed in cleansing and healing whilst fasting, so it is not really surprising to hear that you have experienced problems as a result.
If you were to follow this advice then you would most certainly not experience any problems of deficiency or otherwise whilst fasting......
#1. Eat a high water content and nutrient-dense diet for at least a few months prior to the fast of any length.
#2. Conserve your energies by resting as much as possible during the fast, and not dissipating this energy in working or other activities.
Nature has provided the fast with certain predetermined conditions: animals who fast for whatever reason will rest and sleep as much as possible, because they know instinctively that to do otherwise would be potentially harmful and counterproductive to the fasting process and its innate aims.
You may disagree with me SF re' water being able to deplete minerals from the body, but this is only applicable if these minerals happen to be of an inorganic form, and therefore need to be eliminated from the body; however it is a different story for the organic forms which are bio-available and essential to the body nutritionally where the fasting process conserves these as much as possible.
You should also consider that unnecessary energy- expenditure on a water-fast will "burn" your nutritional resources far more quickly with possible nutrient-deficiency being the end result.
Perhaps you would like to show me some proof of this statement.