On Saturday, Tacko Fall will eat his first meal of the day before 4 a.m.

He won’t eat his next until after 8 p.m.

For the past month, the 7-foot-5-inch Celtics center has been observing Ramadan, a 30-day period of fasting and reflection for Muslims. During that span, Fall can eat and drink only before Fajr, the first of five daily prayers that takes place when the sun begins to rise, and after Maghrib, the prayer that takes place when the sun begins to set.

That means no food and no drinks — not even water — as long as the sun is out.

“It’s challenging,” said Fall. “A lot of times when you would tell people from here that you’re fasting, they’re like, ‘Oh, but you can drink water.’ No, you can’t drink water.”

In addition to fasting, Muslims are encouraged to curb their negative thoughts and abstain from engaging in behaviors such as gossiping and complaining.