How the Western Diet Has Derailed Our Evolution (Nov 2015) summarizes Dr Sonnenburg's research very well. This article is referenced at offset 17:25 of Dr Sonnenburg's talk below.
At offset 1:04:09 in the talk below, Dr Sonnenburg explains her guideline about fiber and how this guideline relates to food habits of contemporary primitive communities and ancient Paleolithic communities. At offset 1:06:30, Dr Sonnenburg mentions that she and her husband have contemplated chalking out this diet:
The One-Rule Diet: Eat As Much Dietary Fiber As Possible!
Dr Sonnenburg explains that by following this rule, all of these go down: saturated fats, sugar, total calories! With this One-Rule Diet, we naturally gravitate towards a Whole Food Plant-Based Diet.
Book: The Good Gut by Justin Sonnenburg & Erica Sonnenburg (320 pages, 2016).
60-min talk by Dr Sonnenburg followed by 30-min Q&A.
A slide from Dr Sonnenburg's talk at offset 18:12. It explains that contemporary Americans consume <15 g fiber on average. RDA for adults is somewhere around 25g - 35g. Dr Greger will cite researchers who recommend 50g and even higher! Primitive societies extant today eat far more: >100g of fiber.
A slide from Dr Sonnenburg's talk at offset 44:25. It summarizes her advice for boosting our microbiome quality: (1) "Feed your microbes" (in other words, "consume fiber; fiber is food for our gut bacteria"), (2) Eat bacteria, (3) Don't over sanitize, (4) Avoid unnecessary antibiotics, (5) Expose yourself to natures's microbes.
A slide from Dr Sonnenburg's talk at offset 49:43. It outlines Sonnenburgs' family strategy for boosting microbiome: gardening, pets, eat mostly plant-based foods, don't be too clean (Dr Sonnenburg describes how they eat carrots from their garden, without scrubbing them 100% clean). The graph is data point for n=1 individual (dad): his microbiome diversity went up with these measures. Microbiome diversity is associated with better health.