Is Fiber the New Protein?

A Starbucks latte now comes with 36 grams of it. The David bar packs 28 grams into 150 calories. There's protein being added in all sorts of forms to chips, pasta, cereal. Even water.

Nothing wrong with that. I aim for 80 or so grams a day (0.7g per pound of ideal body weight) to maintain and build lean muscle.

But the macro that got lost in all of this? Fiber. And most of us are far more fiber-deficient than protein-deficient.

We evolved eating plants, roots, berries, brambles and twigs. Modern hunter-gatherers like the Hadza are estimated to eat 100+ grams of fiber a day. And yet the average American eats about 16.¹ We eat far too much processed, pre-digested, sugary food. Even our protein-packed food is fiber-empty.

Even PepsiCo's CEO says fiber is the next protein. Sort of terrifying, but, he's right. Here's why, how to get enough and which are the right kinds.

What to know: Fiber is the macro most of us are missing.

The old assumption: If you eat "healthy," you're getting enough fiber.

Only about 5% of Americans hit the recommendation.² Most of us think we do.

Fiber is one of the most protective foods you can eat.

Across 40 years of studies, people who ate the most fiber had 15–30% lower risk of early death, heart disease, stroke, type 2 diabetes and colorectal cancer. Benefits peaked at 25–29 grams a day, and the data suggest more is even better.³

• every 10 g a day → 10% lower colorectal cancer risk⁴
• every 7 g a day → 9% lower heart disease risk⁵

❝ Every 10 grams of fiber a day = 10% lower colorectal cancer risk. Most of us are 15 grams short.

Fiber helps you clear estrogen.

Your liver packages used estrogen to send out through your gut. Certain gut bacteria unpackage it so it gets reabsorbed. Fiber turns that recycling down.⁶ Translation: fiber helps you take out the estrogen trash. Women who ate the most fiber had 8% lower breast cancer risk, before and after menopause.⁷

And no, fiber won't hurt your fertility. That idea traces back to one small 2009 study of 250 women over two cycles.⁸ The large studies of women trying to conceive (25,000+ of them) found no harm. Sugar and refined carbs were the problem.⁹¹⁰

Your gut needs time to catch up.

Your gut bacteria turn fiber into butyrate, the main fuel for the cells lining your colon. But in a 10-week Stanford trial, a high-fiber diet didn't increase gut diversity. It did boost the bacteria's fiber-digesting machinery. The group eating fermented foods saw more diversity and lower inflammation.¹¹ Fiber is the long game. Pair it with fermented foods.

Not all fiber supplements are equal.

Psyllium is the one with the receipts. It's the only fiber supplement a gastroenterology task force found enough evidence to recommend for chronic constipation,¹² it's recommended for IBS,¹³ and about 10 grams a day lowers LDL by ~13 mg/dL.¹⁴

Most "added fibers" in bars and sodas (inulin, chicory root, soluble corn fiber) don't do any of that.¹⁵ Including the one in your protein bar.

What to do: Eat your plants first. Let psyllium close the gap.

1️⃣ Aim for 30 grams minimum. 40–50 is my sweet spot.

The official targets for women are 25 grams under 50 and 21 over 50. I think that's a floor, not a goal.

• add ~5 grams a week, not 25 overnight
• drink more water as you go

2️⃣ Get 75–80% of your fiber from food.

Food brings what a powder can't: polyphenols, minerals and a wider range of fibers for your gut bacteria. And it's where the big benefit studies come from.

Here's what a ~45-gram day looks like for me:

• breakfast: 2 Tbsp chia + 1 cup raspberries in my Parsley Rebuild Protein smoothie (16 g)
• lunch: salad with ½ cup lentils + ½ avocado plus grilled steak shrimp (12 g)
• snack: a pear (5.5 g)
• dinner: miso roasted salmon + 1 cup broccoli (5 g)
• psyllium: 2 doses in water with meals (6–7 g)

That's ~85% food. Add ½ cup of black beans at dinner and you're over 50 grams without the supplement.

3️⃣ Use psyllium for the last 20–25%.

Closing a 25-gram gap with supplements alone would take 7–8 doses a day. That's why it's a gap-filler, not a plan.

• choose plain psyllium husk (no sugar, dyes or artificial sweeteners)
• start with 1 dose with a full glass of water
• take it at least 2 hours apart from medications, especially thyroid meds

4️⃣ Count variety, not soluble vs. insoluble.

There's no official ratio. A whole-food diet lands around 3:1 insoluble to soluble on its own, and psyllium tips you toward soluble. Mix beans, seeds, berries, greens and whole grains, and add a daily fermented food: yogurt, kefir, kimchi or sauerkraut.

5️⃣ Bloated? Go slower, not lower.

If you have IBS or SIBO, beans and inulin can flare symptoms. Start with psyllium, which ferments less and is easier on the gut, and add fermentable foods slowly. Bowel obstruction history or gastroparesis or on a GLP-1? Talk to your doctor.

The goal: Keep your protein. Just give fiber the same attention.

Living Longevity

I’m one week into post-CEO life, and it’s both strange and thrilling. What will I do all day, I wondered? Will I freak out and end up in bed with cigarettes and gin, lost and depressed?

So far, not so much. It’s helped that a temporary loss of childcare, a day off from school and my kids’ insane soccer schedule have compressed time a bit. But the whole point of this was to spend more time with my kids. So here I am, living exactly what I called in.

Now I’m in week two and starting to get more intentional. I’m moving my workouts up to 5x a week from 2–3. How glorious to make a 1-hour noon yoga class, fit in that extra gym session that used to feel impossible, or try the new hot Pilates studio my friend has been talking about all year. I swear my abs are already stronger. (I also might be seeing things.)

I’m also clear that each week has a goal, or a set of goals, that I’m prioritizing. And I’m holding space for meditation, spiritual practice, coaching, reading and writing, which takes real effort. Somehow I could already say yes to too much and find my time eaten up by calls I don’t necessarily need to have.

I also have a few longevity talks I’m prepping, for Eudēmonia, A4M, Summit and YPO NYC. That means researching, writing and practicing with my speaking coach. Plus podcasts, and strategic work for Parsley in my new role as part-time Chief Health Officer.

It’s an interesting feeling: I feel full and spacious instead of full and slammed. I’m a little worried I’ll get used to this. But it’s instructive for my nervous system after 11 years of eating, sleeping and breathing my company. Can I be productive and relaxed?

Stress is inevitable. Certainty is all but impossible. So my number one priority, while I explore what feels inspiring, is practicing kindness and compassion: first toward myself, and then amplified out toward the world.

Longevity requires periods of quiet. Moments to reboot the synapses. The fallow periods between eras of growth. I’m in one now, and I’m letting it flow toward me instead of chasing it.

One more thing...

Still not working with a board-certified functional medicine doctor to help you optimize health, prevent disease, and resolve symptoms? WHAT are you waiting for?! Parsley Health is in-network everywhere and our team is incredible. Sign up for our care program today! Your health can’t wait.