Kelly & Juliet Starrett (physical therapist; attorney & ceo) 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.
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 10%.
Fung puts more of the week into intervals: about 12% against 0%.
The Starretts put more of the week into mobility and stability: about 60% against 8%.
In plans in their style, the Starretts' hard sessions are 1-minute intervals; Fung's are 4-minute intervals (Norwegian 4 × 4).
We rate the evidence behind the Starretts' protocol higher: solid, against mostly weak for Fung.
Supplements that go into a plan: the Starretts, none (food first); Fung, none (food first). Prescription items and personal stacks stay out of every plan.
Only the Starretts have 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
Kelly & Juliet Starrett
Walk 8,000–10,000 steps a day, up to 12,000 if you canStrong evidence
Sit on the floor for at least 30 minutes a day, changing positions (cross-legged, 90/90, long sitting)Personal habit
Practise getting down to and up from the floor; test with the sit-and-rise testSome evidence
Daily deep-squat time: hold your deepest squat for five breaths as a test, plus sit-stands from a chairSome evidence
Daily balance practice; test standing on one leg with eyes closed (SOLEC) and putting on shoes while standingSome evidence
Optional rucking: start with about 2 kg for a mile, three times a week, and build up over about a monthPersonal habit
Jason Fung
No specific guidance in what we reviewed.
Eating
Kelly & Juliet Starrett
About 800 g of fruit and vegetables a day (roughly six cups)Strong evidence
Protein about 1.5–2.2 g per kg of body weight; some later talks cite 1.8 g per kgSome evidence
Choose affordable protein sources that fit your budget; perfection is not requiredNote
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
Sleep & recovery
Kelly & Juliet Starrett
Aim for at least 7, ideally about 8, hours of actual sleep; track hours asleep for three nightsStrong evidence
Keep the same bed and wake times, including weekendsSome evidence
Be careful with caffeine and alcohol; keep phones and screens out of the bedroomSome evidence
Keep the bedroom cool, dark and quiet, and allow more time in bed than you think you needSome evidence
Jason Fung
No specific guidance in what we reviewed.
Stress & mind
Kelly & Juliet Starrett
Breath-hold test as a rough benchmark for tolerance of carbon dioxidePersonal habit
Breathe through the nose during the day and in workoutsPersonal habit
Optional mouth-taping at night, building up gradually from about 10 minutesPersonal habit
Spend about 180 minutes a week outdoorsSome evidence
Jason Fung
No specific guidance in what we reviewed.
Weak spots to know
Kelly & Juliet Starrett
Several central tests rest on observational data: the sit-and-rise and one-leg balance studies show that people who do poorly die sooner, not that practising the test makes you live longer. Both studies were also in Brazilian cohorts and could not rule out other explanations.
Some tests have no validated scoring for the general public; the Starretts themselves describe the breath-hold test as a rough benchmark rather than a lab-grade measure, and practices such as mouth-taping have little evidence behind them.
Built to Move deliberately leaves out cardio and strength training; for adults over 50 those remain important for heart health and muscle, so the plan works best as a base layer rather than a complete programme. Kelly's earlier Supple Leopard was criticised by one reviewer for a trial-and-error approach rather than a systematic method.
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 the Starretts, 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.
What is the main difference between Kelly & Juliet Starrett and Jason Fung?
Their training split differs most in mobility and stability: the Starretts about 60%, Fung about 8% (our estimate from their published routines). The Starretts' signature habit is 10 tests, 10 practices; Fung's is Fasting, less sugar.
How much protein do the Starretts and Fung recommend?
The Starretts: 1.5–2.2 g per kg. Fung: No fixed target.
Whose advice has stronger evidence?
We rate the evidence behind the Starretts' protocol higher: solid, against mostly weak for Fung.
Do the Starretts 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 10%.
Can I combine the Starretts 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.