Wheatgrass Yogi
It all has to do with dedication. If you Fast with someone else while you're Fasting, that person can motivate you, but there's a down side as well. They might not be as serious as you are, and become a hindrance...or a distraction.
Before you begin your 'Fast to Completion' (as Mighty calls it), you want to be so Primed for the Fast that everyone else would tend to pull you down. Having someone Fast with you only says you're not really serious about the Fast itself, but would rather make it a social occasion. Now is the time to be Antisocial!!!.....WY
P.S. When Jesus went into the Desert for His 40-day Fast...He went ALONE. Can you picture Him having a 'fasting buddy'??
P.P.S. There are those who feel that Jesus took nothing during this time, not even Water...except for the morning Dew.