A meta-analysis of 10 studies, including 80,139 subjects was recently published that shows a significantly reduced risk of death for all causes in association with higher total dietary fiber intakes (35-39g/day), when compared with lower fiber (Reynolds et al. 2019):

Should we supplement with fiber, or get it from whole food? Fiber from whole foods was significantly associated with lower levels of fasting glucose, body weight, whole body fat mass, LDL cholesterol, and triglycerides. Supplementation with fiber extracts or bran was not significantly associated with the reduction of any of these variables (NS, not significant; NM, not measured:

Reference

Reynolds A, Mann J, Cummings J, Winter N, Mete E, Te Morenga L. Carbohydrate quality and human health: a series of systematic reviews and meta-analyses. Lancet. 2019 Feb 2;393(10170):434-445. doi: 10.1016/S0140-6736(18)31809-9.

If you’re interested, please have a look a my book!