Compare experts › Mark Hyman vs Jason Fung

Mark Hyman vs Jason Fung

Mark Hyman (physician, functional medicine) and Jason Fung (physician, kidney specialist) side by side: how they train, eat, supplement and sleep, how strong the evidence is, and how to build a plan from either or both.

Build a plan from both See the protocols

Words explained (8)

Zone 2: Steady cardio at a pace where you can still talk in full sentences, but not sing.
Intervals: Short hard efforts with easy recovery in between, such as 30 seconds fast, 90 seconds slow.
4 × 4: Four rounds of 4 minutes hard with 3 minutes easy in between. Also called Norwegian intervals.
Mobility: Moving your joints freely through their full range.
Creatine: A well-studied supplement that supports strength and muscle.
Omega-3 (EPA, DHA): Healthy fats found mostly in oily fish such as salmon, herring and sardines.
Polyphenols: Natural plant compounds in foods such as berries, tea, coffee, cocoa and olive oil.
Time-restricted eating: Eating all your meals within a set window of the day, for example 8am to 6pm.

At a glance

Measure	Mark Hyman	Jason Fung
Background	Physician, functional medicine	Physician, kidney specialist
Training split	30% strength · 25% aerobic · 30% intervals · 15% mobility	45% strength · 35% aerobic · 12% intervals · 8% mobility
Signature habit	Pegan diet	Fasting, less sugar
Protein	30–50 g shake after training	No fixed target
Training style	Food as medicine	Fasting
Overall evidence	Mixed	Mostly weak
Following	Instagram 3.8M · YouTube 1.5M	YouTube 1.5M

Training splits are our estimates from each expert’s published routine. Following checked October 2026.

The key differences

Fung puts more of the week into strength: about 45% against 30%.
Fung puts more of the week into aerobic base (zone 2): about 35% against 25%.
Hyman puts more of the week into intervals: about 30% against 12%.
In plans in their style, Hyman's hard sessions are 1-minute intervals; Fung's are 4-minute intervals (Norwegian 4 × 4).
We rate the evidence behind Hyman's protocol higher: mixed, against mostly weak for Fung.
Supplements that go into a plan: Hyman, protein shake with creatine after training, omega-3 fish oil; Fung, none (food first). Prescription items and personal stacks stay out of every plan.
Only Hyman has a mobility or movement routine of their own.

Protocols side by side

Each line is rated for the evidence behind it. “Doctor only” items never go into a plan.

Training

Mark Hyman

Strength training 3–4 times a week, about 30 minutes, mainly resistance bands and moderate weightsStrong evidence
Aerobic or interval training 4–6 days a week, about 30 minutes (cycling, tennis, hiking, swimming)Strong evidence
Yoga a couple of times a week plus a little stretching most daysSome evidence
Avoids very heavy lifting as he ages to limit injury riskPersonal habit
Hypoxia (low-oxygen) training with a machine or maskPersonal habit

Jason Fung

No specific guidance in what we reviewed.

Eating

Mark Hyman

Pegan diet: about 75% of the plate from plants, mostly non-starchy vegetablesStrong evidence
Cut sugar, refined flour and ultra-processed foodsStrong evidence
1–2 cups of cruciferous vegetables (broccoli, cabbage etc.) a daySome evidence
Healthy fats from olive oil, avocado, nuts, seeds and small oily fishStrong evidence
Avoid gluten and most dairy, even without intolerancePersonal habit
Daily overnight fast of 12–16 hoursSome evidence

Jason Fung

Cut added sugar and refined grains; eat whole foods with natural fats.Some evidence
Stop snacking: three meals a day, then skip one meal a day.Personal habit
Eat within a shorter window of the day (time-restricted eating).Some evidence
Fasts of 24 hours (skipping two meals in a row) two or three times a week, as used in his clinic's programme.Personal habit
Longer fasts of several days; in 2016 he said fasts of up to a month were fine.Doctor only
For type 2 diabetes: no sugary drinks, fructose or processed food, and more natural fats.Doctor only

Supplements

Mark Hyman

Protein shake after training: 30–50 g whey (goat) plus 5 g creatineStrong evidence
Vitamin D, fish oil, a multivitamin and magnesium at nightSome evidence
NMN (about 900 mg a day), urolithin A, quercetin, curcumin and similar 'longevity' compoundsPersonal habit
His own branded gut supplement (prebiotics, probiotics, polyphenols)Personal habit

Jason Fung

No specific guidance in what we reviewed.

Sleep & recovery

Mark Hyman

7–8 hours of sleep with a regular bedtime around 10 pmStrong evidence
Dark, quiet bedroom with eye mask and earplugsSome evidence
Blue-light-blocking glasses in the eveningPersonal habit
Steam or sauna and cold plunge most daysPersonal habit
Red light therapy at homePersonal habit

Jason Fung

No specific guidance in what we reviewed.

Stress & mind

Mark Hyman

Meditation once or twice a day plus breathworkSome evidence
As much time in nature as possibleSome evidence
Regular time with friends and familySome evidence
Regular massagePersonal habit

Jason Fung

No specific guidance in what we reviewed.

Weak spots to know

Mark Hyman

Functional medicine as a field lacks randomised trial evidence; surgeon and blogger David Gorski (Science-Based Medicine, 2014; Respectful Insolence, 2019) argues its useful parts (diet, exercise, sleep) are not unique and its unique parts (broad testing, supplements, 'detox') are not proven.
A 2021 Red Pen Reviews analysis of Eat Fat, Get Thin scored its scientific accuracy 1.2 out of 4, finding the claim that saturated fat does not cause heart disease conflicts with most controlled studies.
Commercial ties are large: he co-founded and is chief medical officer of Function Health (direct-to-consumer lab testing) and sells supplements through his own online shop; nutrition scientist Adrian Chavez (Katie Couric Media, 2026) noted one of his supplement stacks supplies 7,000 IU of vitamin D a day, above the usual 4,000 IU upper limit.

Jason Fung

Red Pen Reviews scored The Obesity Code at 31% for scientific accuracy, and The Diabetes Code at 33%.
His central claim that calories do not matter is contradicted by controlled studies.
Much of his support comes from case reports, small older studies and his own clinic.

Build a plan from Hyman, Fung or both

Your free plan shows a week of gym sessions, cardio, a day of eating, supplements and mobility, fitted to your age, time and health.

Plan in Hyman's style Plan in Fung's style Mix both

Questions

What is the main difference between Mark Hyman and Jason Fung?

Their training split differs most in intervals: Hyman about 30%, Fung about 12% (our estimate from their published routines). Hyman's signature habit is Pegan diet; Fung's is Fasting, less sugar.

How much protein do Hyman and Fung recommend?

Hyman: 30–50 g shake after training. Fung: No fixed target.

Whose advice has stronger evidence?

We rate the evidence behind Hyman's protocol higher: mixed, against mostly weak for Fung.

Do Hyman and Fung disagree?

Not directly in what we reviewed. Their differences are in emphasis: fung puts more of the week into strength: about 45% against 30%.

Can I combine Hyman and Fung?

Yes. In Build my mix you choose one expert per area, for example one for strength and another for eating. Your free plan shows the result straight away.

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Full sources are on each profile: Mark Hyman · Jason Fung. Reviewed October 2026.