Fiber, Your Microbiome, and a Simple Plan to Hit Your Daily Target
- Jaime Hernandez
- Sep 21
- 4 min read
Updated: Sep 21
I’m in the studio early, lights low, kettle on. Before the first client walks in, I shake my morning jar—kefir, chia, cacao, matcha, a little collagen, a scoop of creatine, topped with water. It’s part ritual, part science. While I map out someone’s back-pain plan or a return-to-running program, that jar is quietly doing its job—feeding microbes that in turn feed you. That’s the heartbeat of this post: how to get your fiber, why your microbiome cares, and the most practical way to make it happen today—in my voice, with the science behind it, and an easy plan you can follow.
If you’re new here, welcome to Health and Exercise Prescriptions—my home base for evidence-backed coaching, massage therapy, and medical exercise in the Pacific Northwest: healthandexerciseprescriptions.com. And if you’re looking for vetted supplements (when food alone isn’t cutting it), visit my Thorne partner page: thorne.com/u/HealthAndExercisePrescriptions.
How much fiber do you actually need?
Short answer: most adults thrive at ~14 grams of fiber per 1,000 calories, which works out to about 25–28 g/day for many women and 28–38 g/day for many men. That’s the Adequate Intake (AI) established to protect heart health and broadly support metabolic resilience. Most Americans don’t get there—averaging ~17 g/day—so you feel better fast simply by closing that gap. (PubMed)
What fiber does for your gut (and why your mood and energy notice)
Think of fiber as microbe food. Your colon’s beneficial bacteria ferment specific fibers and make short-chain fatty acids (SCFAs)—acetate, propionate, and especially butyrate—that power your intestinal cells, support a tighter gut barrier, tune inflammation down, and even signal along the gut–brain axis. That’s not wellness fluff; it’s one of the best-studied levers we have. (Frontiers)
A powerful bonus: diversity. People eating ~30 different plants per week tend to have more diverse microbiomes—often a marker of resilience. And adding fermented foods (yogurt/kefir, kimchi, sauerkraut) can further increase microbial diversity and lower inflammatory markers—a smart one-two with fiber. (PMC)
Soluble vs. insoluble: do you need a “perfect” ratio?
You’ll hear terms like soluble (the “gel” fibers in oats, beans, psyllium, apples) and insoluble (the “roughage” in whole grains, bran, leafy veg). Both matter. There’s no official, universal ratio—you’ll naturally get a mix when you eat a diversity of plants. Practically, I coach clients to include at least one clearly soluble fiber food at each meal (oats/legumes/fruit/psyllium) and stack the plate with vegetables and intact whole grains for insoluble. For constipation specifically, some evidence suggests a near 1:1 mix of insoluble: soluble can help with stool form and frequency—so if you’re stuck, that’s a reasonable experiment alongside hydration and movement. (UCSF Health)
Quick glossary Soluble (“gel”): slows glucose absorption, can lower LDL; prebiotic. Insoluble (“roughage”): adds bulk, speeds transit; helps you stay regular.
Start low, go slow (and hydrate)
If you jump from 10 g to 35 g overnight, your gut will protest. Increase by ~5 g/week and drink water with meals so fiber can move and do its job. Simple, boring, highly effective. (Mayo Clinic)
A simple, tasty way to hit ~30–35 g today
Here’s a plan I’ve used with clients who want results without counting every gram:
Breakfast – Chia-kefir bowl: 2 Tbsp chia (~10 g) stirred into plain kefir; top with 1 cup mixed berries (~4 g).Subtotal: ~14 g
Lunch – Lentil soup + greens: 1 cup lentil soup (~8 g) and a big salad (mixed greens + veggies, ~3 g).Subtotal: ~11 g (running total ~25 g)
Snack – Fruit + nuts: 1 medium apple (~4 g) + small handful almonds (~3 g).Subtotal: ~7 g (running total ~32 g)
Dinner – Quinoa + roasted veg: 1 cup cooked quinoa (~5 g) + 2 cups roasted broccoli/Brussels/onions (~4+ g).Daily total: ~41 g (plenty of wiggle room—shrink portions to land in your 25–38 g zone).
These are approximate numbers (fiber varies by brand, ripeness, and cooking), but they’re reliable enough for planning. If you struggle to get there with food alone, a psyllium husk supplement is one of the few fibers with consistent evidence for bowel regularity and IBS symptom support. Quality matters—use third-party tested products and adjust the dose slowly. (Lippincott Journals)
My “30-Plant Week” challenge
Keep a running list on your phone. Each unique plant (fruits, vegetables, legumes, whole grains, nuts/seeds, herbs/spices) earns a point.
Aim for 30 different plants by Sunday.
Add one fermented food daily: yogurt/kefir, kimchi, sauerkraut, tempeh, miso.
Layer it onto what you’re already doing—don’t let perfect be the enemy of done.
Why it works: more plant variety → more fiber types → more microbial diversity. Then fermented foods nudge diversity and lower inflammatory tone. Win-win. (PMC)
When should you consider a supplement?
Food first. Period. But when travel, appetite, or medical needs get in the way, partially hydrolyzed guar gum or psyllium can bridge the gap—especially during programs focused on regularity or cholesterol management. See my curated options at the Thorne store: thorne.com/u/HealthAndExercisePrescriptions. As always, match the tool to the job (viscous/soluble fibers for lipids and glycemic control; bulking/gel-forming fibers for regularity). (The Nutrition Source)
Work with me
Want a personalized fiber + microbiome plan integrated with your training, massage, and recovery protocols? Book a session: healthandexerciseprescriptions.com. We’ll map your goals, plan your meals, and align your exercise so all parts reinforce each other.
Target: ~25–38 g/day (or 14 g/1,000 kcal).
Approach: diversity first—30 plants/week + one fermented food daily.
Practice: start low, go slow, hydrate; include both soluble and insoluble daily.
Backup: consider psyllium if food alone isn’t cutting it. (PubMed)
Author Jaime Hernandez LMT, MES, CPT.
Thank you for your time and energy...Be well.