Why did the Arabs start the 1973 War during Ramadan, and did it affect their performance?

As said by bhau, the main impetus for the day of the attack was to coincide with a religious festival of the Israeli side, for advantage.

In my reading on this war, the issue of Ramadan did not come up as a significant factor, nor did the Arab side show signs that would indicate severe supply or troop quality issues. The initial attacks, especially on the Egyptian side, were expertly performed and the first engagements were a rude surprise for the IDF. It took time and hard fighting for Israel to finally gain the upper hand, cross the canal and force an armistice in about 30 days. Syria also made gains in the Golan before being driven off.

The earlier 6 Day War was a stark contrast. Then Israel used a holiday as a cover for a preemptive attack on the Arab side. The initial defeat and confusion did separate many Arab troops from food and water in the desert and the suffering was intense. The Arab armies essentially fell apart in days. Not having water is a serious issue in the Sinai Desert.

The mixed results gave both sides some pause for thought. While Egypt showed themselves they could contend for a time, the quick end to the war did save them from an embarrassing surrender of an entire Army. Israel had suffered worrying losses and their enemies were performing better. Sadat parlayed his relatively good showing into a more secure rule at home which in the end gave him the status to be able to gain the Sinai back at the peace table.

Reasons for Arabs starting the war during Ramadan:

Arab attacked Israel on October 6, 1973. That year, October was the month of Ramadan. But the main reason for attack on this day was Yom Kippur festival, which was on this day. Yom Kippur also known as Day of Atonement, is the holiest day of the year for the Jewish people.

Arabs were defeated in all previous wars with the Israel.

So, Arab (Egyptian and Syrian) military forces launched an attack knowing that the military of Israel would be participating in the religious celebrations associated with Yom Kippur. Therefore, their guard would temporarily be dropped.

The other reason may be Battle of Badr, which was fought by Muhammad himself in the month of Ramadan. This may have considered by Arabs as a good precedent. (I am just speculating this, as the plan to attack Israel was code-named Operation Badr).

Ramadan fasting and Performances:

I tried lot for getting some authentic sources and information on this part of Yom Kippur war or Ramadan War, but yielded no positive results.

So, I am just drawing some conclusions, or you may called it speculations, based on the circumstantial evidences :

1. Egypt was planning for war. So, during planning soldiers may have been following normal routine which is followed before war. The holy month of Ramadan started from September 27 in 1973, nine days before the war. So, choices may have been given to soldiers to fast or not to fast.

2. Even if Arabs soldiers were fasting, there was no significant or decisive impact of their performance on the war. As it is not discussed as the reason for their defeat.

Authentic Sources: (as internet is not yielding any results)

In my opinion the most authentic sources, on this part, will be

1. The Arabic memoir of the soldiers which describes their days of war.

   Such as Al -Nasr Al-Waheed (The Only Victory) which collects the memoirs of five Egyptian generals who planned and fought the 1973 Yom-Kippur War, was published in 2000. It is written by Dr. Mohammed Al-Jawadi. Or Saad el-Shazly's war memoir: The Crossing of The Suez

   But go for memoir of the soldiers, who were actually present in the battle field and fighting. It may be available in the local markets in Egypt or Syria.

2. Directly meeting the Arab soldiers who fought this war.

3. Contact the professors of history in any Arabic university.