Did Moses fast for 81 days straight?

Deuteronomy 9:

9 When I went up on the mountain to receive the tablets of stone, the tablets of the covenant that the Lord had made with you, I stayed on the mountain forty days and forty nights; I ate no bread and drank no water.

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Moses received the Decalogue from God and brought it down from the mountain. In his absence, the Israelites worshipped a calf, which angered him. When he saw their rebellion, he broke the stone tablets. Afterward, he went back up the mountain.

18 Then once again I fell prostrate before the Lord for forty days and forty nights; I ate no bread and drank no water, because of all the sin you had committed, doing what was evil in the Lord’s sight and so arousing his anger.

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Did Moses fast for 81 days straight?

There is a parallel account in Exodus 32:

1 When the people saw that Moses was so long in coming down from the mountain, they gathered around Aaron and said, “Come, make us gods who will go before us. As for this fellow Moses who brought us up out of Egypt, we don’t know what has happened to him.”

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The above happened during Moses' first 40-day fast.

19 When Moses approached the camp and saw the calf and the dancing, his anger burned and he threw the tablets out of his hands, breaking them to pieces at the foot of the mountain. 20 And he took the calf the people had made and burned it in the fire; then he ground it to powder, scattered it on the water and made the Israelites drink it.

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After Moses came down the mountain, there was no mention that he ate anything; there was no mention that he fasted either. If he ate, he had to be careful to go slow and not to overwhelm his digestive system all of a sudden.

27 Then he said to them, “This is what the Lord, the God of Israel, says: ‘Each man strap a sword to his side. Go back and forth through the camp from one end to the other, each killing his brother and friend and neighbor.’ ” 28 The Levites did as Moses commanded, and that day about three thousand of the people died. 29 Then Moses said, “You have been set apart to the Lord today, for you were against your own sons and brothers, and he has blessed you this day.”
30 The next day Moses said to the people, “You have committed a great sin. But now I will go up to the Lord; perhaps I can make atonement for your sin.”

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There was at least one day in between the two 40-day fasts. I suspect Moses did eat and drink something during the in-between periods. He probably didn't fast more than 80 days straight.