Where did the Buddha speak of his difficulty in eating almsfood as a Bodhisatta? In this answer, I mention that the Bodhisatta had trouble keeping down coarse alms food, to the extent that he felt like his stomach was going to leap out of his throat. @ThiagoSilva asked in a comment where the story is found, and I can't quite remember. Does anyone have a reference handy?
EDIT: Here's an example of how the passage is described, though no mention of where it comes from:

Having enjoyed the kingly bliss which was as great as that of a Universal Monarch only a matter of days ago, he made an effort to eat a morsel of food which was a mixture of coarse and fine edible things in assorted colours. As he was about to put the morsel into his mouth he felt miserable and almost vomited with the intestines turning upside down, for he had never seen such kind of food in his life and found it particularly disgusting. Then he admonished himself by saying; &quot;You Siddhattha, in spite of the fact that you have been reigning supreme in a palace where food and drinks are available at your pleasure and where you have meals of three-year-old seasoned fragrant rice with different delicacies whenever you like, you, on seeing a recluse in robe of rags contemplated, &quot;When shall I eat the meals obtained by going on alms round from house to house after becoming a recluse like him? When will the time come for me to live on meals thus collected? And have you not renounced the world and become a recluse with such thoughts? Now that your dream has come true, why do you like to change your mind?&quot; Then without the slightest revulsion he took the meal that was so rough.
(source)
I found it in the introduction to the Jatakas, which seems to be the original source:

Now the Great Being, after collecting a number of scraps, sufficient, as he judged, for his sustenance, left the city by the same gate he had entered, and sitting down with his face to the east, in the shade of Pandava rock, he attempted to eat his meal. But his stomach turned, and he felt as if his inwards were on the point of coming out by his mouth. Thereupon, in the midst of his distress at that repulsive food, --for in that existence he had never before so much as seen such fare,--he began to admonish himself, saying, &quot;Siddhattha, although you were born into a family having plenty to eat and drink, into a station in life where you lived on fragrant third season's rice1 with various sauces of the finest flavors, yet when you saw a monk clad in garments taken from the rubbish heap, you exclaimed, 'Oh, when shall I be like him, and eat food which I have begged? Will that time ever come?' And then you retired from the world. And now that you have your wish, and have renounced all, what, pray, is this you are doing?&quot; When he had thus admonished himself, his disgust subsided, and he ate his meal.
-- Jāt-A nidānakathā (from Buddhism In Translations, Henry Clarke Warren, trans.)

The relevant Pali is &quot;antāni parivattitvā mukhena nikkhamanākārappattāni viya ahesuṃ&quot; - It was like the intestines, having churned, attained the state of leaving through the mouth.&quot;
The Buddhavamsa doesn't mention this reflection, saying of his first alms round simply:

nisīditvā āhāraṃ paccavekkhitvā nibbikāro paribhuñji
Having sat down, having reflected on the food, unperturbed, he ate.
-- Bv-A, nidānakathā