36 months, that is, 3 years. Dietary fiber is a kind of polysaccharide, which can neither be digested and absorbed by gastrointestinal tract nor produce energy. Therefore, it was once considered as a "non-nutritive substance" and has not been paid enough attention for a long time. However, with the in-depth development of nutrition and related sciences, people gradually found that dietary fiber has very important physiological functions. According to different people's eating habits, the effect of dietary fiber powder varies greatly: if you consume enough dietary fiber every day, then this product is basically useless. If the daily intake of dietary fiber is insufficient or unclear, then this product is similar to calcium tablets and protein powder. If it is missing, it will be filled. If there is no shortage, it will be harmless.