I don’t know you didn’t just look it up.
From their website:
Decrease your food consumption. We can’t go 40 straight days without food, but we can decrease the amount we eat. Perhaps we limit our portion sizes so that we eat enough to power our day—but not enough to fully satisfy ourselves. Or maybe we decide not to snack between meals. Perhaps we can even skip a meal. Any time we eat less than we’d like, we’re trusting Jesus’ words “One does not live by bread alone, but by every word that comes forth from the mouth of God” (Matthew 4:4).The key here is to use good judgment. Our goal is to draw near to the Lord, not to pass out from malnourishment. If you decide to limit your food consumption, make sure your fasting plan makes sense in accordance with your state of life. After all, there’s nothing pro-life about going without food for a day if you’re an expectant mother or work with heavy machinery for a living!
Give up a certain type of food. The night before each 40 Days for Life campaign begins, I like to treat myself to the most delicious hot fudge sundae I can find. And then I set sweets aside until after the campaign. Another food we might give up is meat, which is often eaten to celebrate God’s blessings. This was true in Jesus’s time as the return of the prodigal son was celebrated by feasting on the fatted calf (Luke 15: 11-32). It’s equally true in our time. Just think of your Thanksgiving turkey or perhaps an Easter lamb. During 40 Days for Life, we can eat simpler meals focused more on fruits, vegetables and grains. If you find yourself saving money on your grocery bill as a result, you can even contribute the savings to your local pregnancy center.
Turn down the temperature on your morning shower. Fasting doesn’t have to involve food. A nice, steamy shower is a rather comfortable way to start the day. But during 40 Days for Life, we can give up those hot showers. Of course, I’m not suggesting you give up showering altogether for these 40 days. That would be imposing a sacrifice on your loved ones! But you can turn down the temperature. A lukewarm shower gets you clean just as well as a hot one. If you’re truly daring, you might even go with cold showers for 40 days.
Replace your beverage of choice with water.
Fast from media.