It is said that Shakyamuni Buddha, after his Great Awakening, during the 49 days that he spent in the vicinity of the Bodhi tree, fasted. I'm not convinced that this is so.
As all Buddhist traditions agree on the main events of Shakyamuni Buddha's life, though not on the words he spoke on such occasions, it is unnecessary here to list the sources of the following.
Before the attainment of Buddhahood Gautama, the ascetic, practiced a variety of tapas strenuous ascetic exercises, as known to us from both historical accounts and today's Sadhu's practices. The practices originate in the pre-Hindu religious systems. There were practices such as sitting between five fires (4 actual fires and the scorching sun overhead), and there was, and still is the practice of fasting. These practices were intended to liberate man's soul, his purusha, so as to allow it to unite with Brahman or Atman, the All-Soul -- meaning a liberation from the round of birth and death.
The last tapas the bodhisattva Gautama practised was fasting. Scriptures say that he, at last, ate only one grain of rice a day. This needs elucidation. An Asian, living in a culture (India) where mendicant religious people go around doesn't give but one grain of rice, s/he fills the begging bowl with at least a handful. What the accounts mean, therefore, is that the future Buddha didn't eat properly for an extended period of time and it is likely that he only fed on one or two left-over grains, either left by commoners after meal or by ascetics not practicing fasting.
After some time the bodhisattva was skin-and-bones. When one day he bathed in the Neranja river, he consequently collapsed, fell into the water and nearly drowned. We must remember that the Buddha, even in his pre-Buddha stage, deliberately chose the life of a man, not that of a super-human. Though during his life, both previous to and after his Awakening he performed miracles, he decided to fully demonstrate his own saying that all things, though empty (1) and unborn (2) will somehow come to an end. This is demonstrated by the episode where the Buddha, just before dying, asks his attendant Ananda: (free translation) Shall I use my powers to live on or shall I die as all men do? As Ananda failed to produce an answer the Buddha decided not to remain in this world.
In fact, during his lifetime the Buddha fell ill once or twice. He probably had, what we call now, gastric problems, as a result of his prolonged fasting during his pre-Buddha career.

Back to the beginning, to the Neranja river. Once the bodhisattva Gautama had managed to step out of the water he sat under a tree and said to himself: man, this is not going to work. Practicing tapas brought liberation to neither me, nor to my gurus. There must be another way.
As he was the Buddha-to-be the right thing happened: lady Sujata brought him a bowl-full of rice enriched with honey and thick milk. The accounts say that he ate the bowl's content -- which is very unlikely. Everyone who practically completely fasted for a prolonged period of time knows that in the end eating more than, say, a few spoon-fulls of soup already causes stomachache. Again, the future Buddha, at that stage chose the life of a man, not that of a super-human being, which is to say that he allowed his body to function like that of an ordinary human being. It is therefore likely that he took just one or two hand-fulls of Sujata's dish, just enough to allow him to wade to the other bank of the river. There he sat under a peepal tree to experience this often described night of Complete Enlightenment.
After this night he spent the next 49 days in that same area.
At the end of these 49 days Shakyamuni Buddha decided to first instruct his former five ascetic-companions who resided in the Deer Park near Benares. When they saw him coming they said to one another: the ascetic Gautama has given up his tapas; he looks well fed; he must have gone back to the commoner's life; we will not offer him a seat, we will not pay respect. (After all they nevertheless offered a seat and paid respect.)
We must pay attention to these ascetics' words describing the Buddha as well groomed or well fed.

A leap forward. Today there are reports that meditating monks, having their alms bowl besides them during their retreat, are fed by generous donors who come and quietly fill these bowls with food. Something similar may have happened to Shakyamuni Buddha during these 49 days. To this day it is unimaginable that Indians, having a holy man in or just outside their village, should not take care of him. Such, in fact, would be bad karma, unwholesome action leading to unpleasant results in the future.
Another reflection that sustains my conviction that the Buddha did not fast during these 49 days: The distance between Gaya where the Buddha Awakened and Benares is quite long, especially for those who walk this distance barefoot.

It is very unlikely that a man who nearly completely fasted for a prolonged period of time, and then ate a handful of enriched rice, and then did not eat for another 49 days, should set out on a long-distance walk from Gaya to Benares, let alone that he should arrive there as a "well fed" man.

The relevant sutra passages that describe his Great Awakening and the weeks after do not say that the Buddha, during his 49 days retreat, ate. Neither do they say that he did not eat. But considering the events following his Awakening, it is very unlikely that he fasted.

At no moment during his career did Shakyamuni Buddha preach fasting. There is no Buddhist Scripture (sutra) in which fasting is recommended.

Notes:
1: empty (sunyata) - devoid of an abiding self; for its coming to be dependent on causes and conditions (circumstances), therefore mirage-like.
2: devoid of self-nature (according to Lankavatara sutra)