So Wikipedia isn't as impartial as one would have supposed, and is the experience of many Alt' Health Professionals.
Absolutely, when the urine turns from dark to clear is an indication of the need to break the fast, but this has always been considered by the vast majority of qualified Fasting supervisors to be of secondary importance to the return of natural hunger: along with the other secondary symptoms..........................
Shelton describes it thus and quotes CARRINGTON as well.............
The Breath, which during all or most of the fast has been offensive, becomes sweet and clean.
The Tongue becomes clean. The thick coating which remained on it throughout most of the fast vanishes.
The Temperature, which may have been sub-normal or above normal, returns to exactly normal, where it remains.
The Pulse becomes normal in time and rhythm.
The Skin reactions and other reactions become normal.
The Bad Taste in the mouth ceases.
Salivary Secretion becomes normal.
The Eyes become bright and eye sight improves.
The Excreta loses its odor. The Urine becomes light.
"Besides the usual signs that it is time to break the fast, Prof. Levanzin lists a feeling of cheer and elation as a manifestation that the time has arrived for the termination of the fast. I cannot do better than quote Hereward Carrington's description of the feelings of the patient at this stage. He says, "Vitality, Fasting and Nutrition, p. 544": "A sudden and complete rejuvenation; a feeling of lightness, buoyancy, and good health steals over the patient in an irresistible wave; bringing contentment and a general feeling of well-being, and of the possession of a superabundance of animal spirits."
"The primary indication that the fast is to be broken is the return of hunger; all the other indications which I have enumerated are secondary. Often one or more of these secondary signs are absent when hunger returns, but one should not refrain from breaking the fast when there is an unmistakable demand for food, merely because the tongue, for example, is not clean. Inasmuch as all the signs do not invariably appear in each case, do not hesitate to break the fast when hunger returns"............... http://www.soilandhealth.org/02/0201hyglibcat/020127shelton.III/020127.ch30.htm
Exercise is fine during the fast but it depends on the reasons for so doing. The unhealthy and diseased would not benefit that much if at all, whereas Shelton would recommend it for those wishing to lose weight.
It has since been discovered that Fasting is not the most ideal way of losing weight because of the lowered rate of metabolism, some prefer it and some don't, and where a plant-based diet that is properly combined achieves this just as well. http://www.drfuhrman.com/weightloss/default.aspx