Hello roxy33,
I would beg to disagree with your perceived "insulin-surge" from fructose within fruit and their juices on breaking your fast making you uncontrollably hungry, and for the following reasons.............
Ordinary table
Sugar (cane or beet sugar, sucrose) and grape
Sugar (glucose) are absorbed from your digestive tract relatively quickly, causing your pancreas to release a lot of insulin which is the natural hormone required to metabolize the sudden big surge in your blood
Sugar levels. The average amount that your blood sugar rises after you eat a given amount of a particular carbohydrate is called that carbohydrate's glycemic index.
The natural fruit sugar fructose has one of the lowest glycemic indexes of any food - with a rating of only 20, compared to 31 for skim milk, 59 for sucrose (ordinary table sugar), and 98 for an equal weight of mashed potatoes. This means that 1 ounce of fructose raises your blood sugar by only about 1/3 as much as an ounce of sucrose, and it releases only about 1/3 as much insulin. A mashed potato raises your blood sugar almost 5 times higher than a comparable amount of fructose!
High glycemic index carbohydrates can cause major problems for your body's fat control program.
I would think that this perceived hunger is most probably psychological rather than anything that is tangible, after all, many fasters "feel" hunger on their fasts, but in reality is just an illusory feeling or what has been described as "toxic hunger".
The "low" you are feeling right now is unbearable to the "high" you felt while fasting, because your digestive energy was used elsewhere in cleansing/healing, and in the mental processes in a heightened feeling of euphoria...............................
"The mental effects of fasting have been known for ages and have been much discussed by all writers on fasting. A few years ago a group of young men and women at the University of Chicago lived for one week without food. During this period they attended their classes and engaged in their usual sports, following out their usual routine. Their mental alertness was so much greater during the period that their progress in their school work was cited as remarkable. Several repetitions of this experiment, always with the same results, proved that this was not exceptional.
All the purely mental powers of man improve while fasting. The ability to reason is increased. Memory is improved. Attention and association are quickened. The so-called spiritual forces of man--intuition, sympathy, love, etc.--are all increased. All of man's intellectual and emotional qualities are given new life. At no other time can the purely intellectual and aesthetic activities be so successfully pursued as during a fast"..................
http://www.soilandhealth.org/02/0201hyglibcat/020127shelton.III/020127.ch11.htm
But once eating is resumed, that digestive energy (the most energy-consuming task of the body) is used in the work of digestion and taken away from the mental processes leaving a low feeling commonly experienced by fasters, and especially if too much food is consumed post fast.
Proper food combining creates far less of a drain on that energy, and leaves it free in accomplishing other tasks required by the body.
Chrisb1.