1. I found a very interesting discussion on this topic in Chashukei Chemed, Berachos 50a, page 302, by Rav Yitzchak Zilberstein shlita. He discusses whether eating at the tables of a restaurant placed outside on the sidewalk, or eating on a bus, is considered as Ochel b'Shuk.

a) Rav Zilberstein cites the Rambam (Hilchos Edus 11:5) who says that it is only someone who walks and eats in the street who is disqualified from giving testimony, and therefore the outside tables or eating on the bus would not make the person Pasul. However, the Chashukei Chemed adds that these activities are not suitable for a Talmid Chacham.

b) At any rate, we see that Rav Zilberstein considers a person who does actually walk when eating in the street as unfit for Edus even nowadays.

c) I would also add that the Gemara in Gitin 70a tells us that it is unhealthy to eat while standing up.

2. This question is also posed by the Igros Moshe (Orach Chayim 2:57), who discusses the Halachos of reciting Berachos for people who walk while chewing gum or eating candies. The question is, how is one allowed to eat candies anyway when walking, if doing so disqualifies him from Edus?

a) An answer can be given according to Rabeinu Tam, cited by Tosfos in Kidushin (40b, DH v'Yesh), who maintains that eating in the marketplace refers specifically to eating a meal with bread. According to this, candies would not come into this category.

b) Another solution may be suggested according to the opinion of the Bach on the Tur in Choshen Mishpat (34:29). The Bach addresses a problem based on the Talmud Yerushalmi, cited by the aforementioned Tosfos, which states, "It is not praiseworthy for a Talmid Chacham to eat in the street." The question is that eating in the street renders one an invalid witness, so why does the Yerushalmi imply that it is merely something which only a Talmid Chacham should avoid?

The Bach answers that it is praisewothy for a Talmid Chacham to refrain even from drinking a drink such as brandy in the street. We learn from the Bach that drinking brandy in the street would not make one invalid as a witness. If so, we can say that chewing gum or sucking a candy would also not make one invalid.

c) A Talmid Chacham here in Yerushalayim suggested to me that the whole question might not begin in the first place, because the Rambam writes that the problem is that this person eats "in front of the entire people." If someone is sucking a candy, other people probably cannot notice that he is eating at all.

3. Regarding eating while standing up:

a) First, it should be stressed that this is a totally different issue from the question of eating while walking in the street. The latter law is recorded in the Rambam and Shulchan Aruch and can disqualify a person as a witness. In contrast, sitting down for eating is a praiseworthy habit, but it is not obligatory according to the Halachah.

b) I wrote earlier (in point 1-c) that the Gemara tells us that eating while standing is unhealthy. In addition, we find in chapter 5 of Maseches Derech Eretz Zuta (printed in the standard editions of the Gemara after Maseches Avodah Zarah) that "a Talmid Chacham should not eat standing up." We note that this is the practice prescribed for a Talmid Chacham, not everyone.

c) We also find that the Rambam (Hilchos De'os 4:3) writes, "Always when a person eats he should sit in his place or lean on his left side." However, we know that Hilchos De'os does not represent binding Halachah, but rather good advice.

d) Proceeding to the Shulchan Aruch, we find that sitting down for eating is not mentioned explicitly. However, there is a section in Shulchan Aruch (Orach Chayim 170) with Mussar (ethical conduct) which a person should practice at mealtimes. The Be'er Heitev there (#16) cites the Roke'ach who says that it is Derech Eretz not to eat or drink while standing up. The Mishneh Berurah (286:6) also writes that l'Chatchilah one should not drink while standing.

e) Finally, the Ben Ish Chai (in Teshuvos Rav Pe'alim, Orach Chayim 2:45) writes that nowadays people are not careful to avoid eating or drinking when standing. He writes that it may be that nature has changed since the time of the Sages of the Mishnah and Gemara, and such conduct is no longer unhealthy.

4. Now to the question about the difference between the issue of eating while walking in the street and the Shitah of the Aruch ha'Shulchan (Orach Chayim 75:7) concerning saying a Berachah in the presence of a married woman who does not cover her hair.

a) Since I am not aware that any leading contemporary authority has ruled that the Halachah concerning witnesses who eat while walking in the street has changed in our times, I am therefore going to pose the question in a slightly different manner: What is the difference between the Halachah of saying a Berachah in front of married women who do not cover their hair, which has changed according to the Aruch ha'Shulchan, and accepting the testimony of someone who eats while walking in the street?

b) I suggest the following answer. The Halachah of the Aruch ha'Shulchan is a secondary Halachah. What I mean is that the Aruch ha'Shulchan does not say that there has been any change concerning the obligation of married women to cover their hair. They have the same obligation to do so as they always had. What has changed is the secondary issue concerning the man reciting a Berachah when looking at her hair. Relating to this issue there has been a change because hair, in the time of the Aruch ha'Shulchan, had become a "revealed place" of a woman, in the same way that her face was a revealed place in former times. The consequence of this is that seeing a woman's hair was no longer a cause for improper thoughts, because society had become accustomed to woman not covering their hair, so the hair did not affect men's thoughts when saying the Shema or blessings. However, concerning a married woman's obligation to cover her hair, nothing has changed, as this is something that she is obligated to do as she always was.

c) The issue of walking and eating in the street is different. This is not a secondary issue; it is a primary issue. What I mean is that if someone eats while walking in the street, this is considered as representing a serious lack of self-respect. Such a person is lacking a feeling of shame. One of the consequences of a person lacking a feeling of shame is that he may not be ashamed to lie in a court of law. We have no guarantee that this fact has changed between our times and former times. The whole issue is a primary issue because there is only one question involved: does this person have a feeling of shame? (See also Teshuvos Mishneh Halachos 15:61-62.)

Dovid Bloom