(Source #3): R. Yosi learns (that eating includes drinking) from here - (Mishnah in Maseches Shevuos 3:1) (If a person made an oath by saying...) 'An oath that I will not eat...' and he ate and drank, he is only liable once.' (This shows that eating includes drinking.)

(Chevraya to R. Yosi): From the latter statement of that Mishnah - 'An oath that I will not eat or drink' and he ate or drank, he is liable twice', (it shows that eating does not include drinking)...?

Rebuttal (R. Yosi to Chevraya): If a person had in front of him two loaves and he said, "An oath that I will not eat this loaf'' and then he said, "An oath that I will not eat from that loaf'', would he not be liable twice? (By mentioning in the earlier case 'I will not eat or drink', he showed that he wishes to differentiate.)

Source #4 (R. Chananya citing R. Pinchas): (Mishnah in Shevuos 3:4) '"An oath that I will not eat'' and he ate food that is inedible or drank liquids that are undrinkable, he is exempt.' But if drank liquids that are drinkable, he would be liable, even though his oath was against eating.

Rebuttal: That's fine according to our text in the Mishnah there, that says 'an oath that I will not eat', but according to the Rabbanan whose text reads 'an oath that I will not eat or drink', there's no proof.

Source #5 (R. Chinana): 'If he ate and drank in one spell of inadvertency, he is only liable once.' (This shows that eating includes drinking.)

Source #6 (R. Abba Mari): The pasuk states (Devarim 26:14), "I did not eat from it {Ma'aser Sheni} in my mourning'' - and would drinking have been permitted? Rather, eating includes drinking.

Question: Until here we have only seen that if a person made an oath against eating and he then drank, that he would be liable. But if he made an oath against drinking and he ate, would he also be liable?

Answer: Drinking is included in eating but eating isn't included in eating.

Source #7: The pasuk states (Devarim 12:17), "You may not eat in your gates Maaser of grain, wine and oil. 'Vetiroshecha' refers to wine and 'Veyitzharecha' refers to rubbing oil and the Torah calls them both eating.

Rebuttal: The teaching from the word 'Veyitzharecha' is not a full Drasha from the Torah, as if it would be, one would incur lashes for rubbing it outside of Yerushalayim.