Question: If one washes his hands and then sometime during the meal decides not to any more bread, what must one do?
Answer: In the previous Halachot we have explained that one who eats less than a Kebeitza (approximately fifty grams) of bread, one must wash his hands without reciting a blessing. If one eats less than a Kezayit (twenty-seven grams) of bread, one need not wash his hands at all.
Now our question is better understood. If one washes his hands with the intention of eating a large amount of bread and then changes his mind and decides not even to eat a Kebeitza amount of bread, is such a thing permissible? If one does not eat at least a Kebeitza of bread, the “Al Netilat Yadayim” blessing that one recited beforehand will have been in vain!
The Ritba discusses this issue (in his commentary on Chullin 106b) and writes: “One who washes his hands for a bread meal, recites the ‘Al Netilat Yadayim’ blessing, and then changes his mind and does not eat, this is no problem and we do not obligate him to eat so that his blessing is not (retroactively) in vain, for at the time he washed his hands, he was obligated to do so since he still intended to eat at that point. I have shared this ruling with my teacher, may Hashem protect him, and he agreed with me.”
This means that since our Sages instituted that one who wishes to eat more than a Kebeitza of bread must wash his hands and recite a blessing, if one intends to eat this amount of bread, one must wash his hands and recite the appropriate blessing. Immediately after one concludes washing his hands, one is no longer obligated to eat bread and if one does not eat, one’s blessing will not have been in vain.
Maran Rabbeinu Ovadia Yosef zt”l (in his Responsa Yabia Omer, Volume 1, Yoreh De’ah, Chapter 21) supports the Ritba’s opinion with sources from the Gemara and writes that this is indeed the correct Halacha and thus, one who washes his hands is no longer obligated to proceed and eat a Kebeitza of bread.
Nevertheless, the Sedeh Chemed writes that not all authorities agree with the Ritba. Therefore, although halachically speaking, the law follows the Ritba’s opinion, Maran zt”l writes in his Halichot Olam, Volume 1 (page 116) that if possible, one should preferably eat a Kebeitza because of the blessing he has recited.
Summary: If one washes his hands and recites the “Al Netilat Yadayim” for a bread meal and then changes his mind and does not wish to eat a Kebeitza of bread, one need not push himself to eat it. If at all possible, one should preferably eat a Kebeitza of bread in order to fulfill all opinions.