Is the Mifflin-St Jeor Equation Still Accurate in 2026? What Recent Research Shows

Medically reviewed for accuracy against peer-reviewed nutrition research. Last updated: August 2026.

Search "Mifflin-St Jeor equation 2026" and you'll find a lot of pages that don't really answer the question. Some just repeat the 1990 formula. Others slap "2026" into a title without citing anything published more recently than the original paper. So here's a straight answer, backed by research actually published in the last two to three years: no, the formula itself hasn't changed — but the research testing it absolutely has, and it's worth knowing what that research found.

Has the Formula Itself Changed?

No. The Mifflin-St Jeor equation is exactly what Dr. Mark Mifflin and Dr. Sachiko St Jeor published in the American Journal of Clinical Nutrition in 1990, and it hasn't been revised since:

For men:

BMR = (10 × weight in kg) + (6.25 × height in cm) − (5 × age in years) + 5

For women:

BMR = (10 × weight in kg) + (6.25 × height in cm) − (5 × age in years) − 161

Predictive equations like this one are statistical models fit to a specific dataset — Mifflin and St Jeor's original 498 healthy adults. There's no ongoing committee updating the coefficients each year. What does change, continuously, is the research testing whether those 1990 coefficients still hold up against new populations measured with modern equipment. That's the part worth paying attention to.

What Recent Research Actually Found

Here's what's been published recently — not vague claims of "2024 research confirms," but specific studies with named authors, journals, and numbers.

A 2025 study in Archives of Public Health tested nine predictive equations against indirect calorimetry in 149 young Emirati women across all BMI categories. Mifflin-St Jeor came out as the most accurate of the nine. The researchers also built a new, cohort-specific equation tailored to that population, which performed slightly better still — though they noted it needs independent validation before it can be trusted the way Mifflin-St Jeor already is.

A 2024 study from Antwerp University Hospital, published in Clinical Nutrition ESPEN, measured resting metabolic rate in a Caucasian population living with overweight or obesity. Mifflin-St Jeor and the Henry equation had the highest accuracy and lowest bias among the equations tested.

A 2024 commentary in Nutrients, responding to a Colombian validation study, noted that Mifflin-St Jeor showed only "moderate correlations" with measured REE in that population, with meaningful bias — enough that the original study's authors built an entirely new equation for Colombian adults rather than relying on Mifflin-St Jeor as-is.

Recent Studies at a Glance

The Honest Complication: Newer Research Doesn't Always Favor Mifflin-St Jeor

This is the part most comparison articles skip, because it complicates the tidy "Mifflin-St Jeor wins" narrative.

A large cross-validation study — over 3,000 participants, published in Frontiers in Nutrition — compared five predictive equations against measured RMR using body composition data from DEXA scans. Mifflin-St Jeor underestimated RMR by about 12.6% on average in that sample. That's a real error margin, and in this particular dataset, both the Harris-Benedict equation (−8.2%) and the WHO/FAO/UNU equation (−2.1%) showed less bias than Mifflin-St Jeor did.

Separately, a study of young Chilean women with excess body fat found that all the standard equations, including Mifflin-St Jeor, overestimated resting metabolic rate — Mifflin-St Jeor was the least biased of the group, but the researchers were explicit that it was "not exempt from inaccuracy."

None of this means Mifflin-St Jeor has fallen out of favor. It means accuracy rankings between formulas shift depending on the specific population being tested, and no single equation — including Mifflin-St Jeor — wins in every study. That's a more honest picture than most "which formula is best" articles give you.

Why Researchers Keep Building New Equations

If Mifflin-St Jeor already works reasonably well, why are researchers still publishing brand-new formulas in 2024 and 2025?

Because "reasonably well" is a population-level statement, and clinicians increasingly want equations tuned to specific groups — a particular ethnicity, a particular BMI range, a particular clinical setting — rather than one formula stretched across everyone. The 2025 Emirati study and the Colombian equation mentioned above are both examples of this trend: not attempts to replace Mifflin-St Jeor for general use, but attempts to do better for a specific population Mifflin-St Jeor wasn't originally built around.

The Academy of Nutrition and Dietetics has reviewed this cumulative body of research — spanning studies from the 1990s through the 2010s — and continues to recommend the Mifflin-St Jeor equation, using actual body weight, as the default for estimating resting metabolic rate in adults, including those with overweight or obesity.

So Should You Still Trust Mifflin-St Jeor in 2026?

Yes, with the same caveat that's been true since 2005: it's the best general-purpose starting point available, not a precise measurement of your individual metabolism. The 2023–2025 research summarized above doesn't overturn that — if anything, it reinforces it, by showing Mifflin-St Jeor performing competitively (though not perfectly) across a range of new populations tested with modern methods.

If you want to see how Mifflin-St Jeor compares directly against the other major formulas, read our breakdown of Harris-Benedict vs. Mifflin-St Jeor, or get your own number with our Mifflin-St Jeor calculator.

Frequently Asked Questions

Is the Mifflin-St Jeor equation from 1990 outdated?

The equation's math hasn't changed, but "outdated" isn't the right word — recent 2024–2025 studies continue to validate it as one of the more accurate widely-available formulas, even against modern comparison methods.

Has Mifflin-St Jeor been replaced by a newer formula?

No single formula has replaced it for general use. Some 2024–2025 studies have built population-specific equations (for particular ethnic groups or clinical populations) that slightly outperform it in those narrow contexts, but none has been adopted as a general replacement.

Why do some 2024 studies show Mifflin-St Jeor being less accurate than expected?

Accuracy varies by the population tested. In at least one large 2023 cross-validation study, Harris-Benedict and the WHO/FAO/UNU equation showed less bias than Mifflin-St Jeor. No formula, including Mifflin-St Jeor, is the most accurate in every single study.

Is there a 2026 version of the Mifflin-St Jeor equation?

No. There is no official "2026 update" to the formula. Recent research validates or refines understanding of the original 1990 equation rather than replacing it.