Just another tradition and piece of religion invented by humans, not from the scriptures. The word of God says nothing about having to give up something important for 40 days. It is human religion, not godliness.
18 Let no one disqualify you, insisting on asceticism and worship of angels, going on in detail about visions, puffed up without reason by his sensuous mind, 19 and not holding fast to the Head, from whom the whole body, nourished and knit together through its joints and ligaments, grows with a growth that is from God.
20 If with Christ you died to the elemental spirits of the world, why, as if you were still alive in the world, do you submit to regulations– 21 “Do not handle, Do not taste, Do not touch” 22 (referring to things that all perish as they are used)–according to human precepts and teachings?
23 These have indeed an appearance of wisdom in promoting self-made religion and asceticism and severity to the body, but they are of no value in stopping the indulgence of the flesh. (Colossians 2:18-23; ESV)