A Comparison of Commonly Used Prediction Equations for Estimating Resting Metabolic Rate in Adults With Down Syndrome.
Use the Bernstein fat-free mass equation—not Harris-Benedict or Mifflin—when you estimate resting metabolic rate for adults with Down syndrome.
01Research in Context
What this study did
Researchers tested eight common formulas that predict resting metabolic rate (RMR). They compared each formula to real, measured RMR in 25 adults with Down syndrome.
The team used a metabolic cart to measure actual calorie burn at rest. Then they ran the numbers through equations like Harris-Benedict, Mifflin-St Jeor, and Bernstein fat-free mass.
What they found
Only the Bernstein fat-free mass equation matched the true RMR. The other seven formulas over- or under-estimated calories by large margins.
For example, Harris-Benedict overshot by more than 200 calories a day. That error could lead to unwanted weight gain or loss.
How this fits with other research
Lyall et al. (2025) also checked if a quick score (SRS) lines up with a gold-standard diagnosis in autism. Both papers show that popular shortcuts can mislead unless they are first checked against real data.
Mumbardó-Helles et al. (2017) meta-analysis reminds us that labels and context matter when we test any tool in intellectual disability. The RMR finding echoes that call: pick equations that were built for, and tested on, the exact group you serve.
Gaily et al. (1998) validated the Environmental Rating Scale for adults with autism using the same step-by-step psychometric method. Their work and the RMR study together push the field to prove—not assume—that our measures work for neurodivergent adults.
Why it matters
If you write meal plans, prescribe exercise, or track weight for adults with Down syndrome, swap in the Bernstein fat-free mass equation today. You will set safer calorie targets and avoid the big errors seen with the old standbys. Share the new numbers with dietitians and caregivers so everyone works from the same, accurate baseline.
Want CEUs on This Topic?
The ABA Clubhouse has 60+ free CEUs — live every Wednesday. Ethics, supervision & clinical topics.
Join Free →Open each adult-Down-syndrome file, delete the old RMR number, and recalculate it with the Bernstein fat-free mass equation.
02At a glance
03Original abstract
BACKGROUND: Resting metabolic rate (RMR), the energy required by the body at rest, is the largest part of total daily energy expenditure. Commonly used prediction equations may overestimate RMR in adults with Down syndrome (DS). The purpose of this study was to assess the equivalency of prediction equations for estimating RMR in adults with DS. METHODS: Twenty-five adults with DS (24 ± 5 years of age, 64% female) completed RMR assessments at an academic medical centre in the United States between November 2021 and July 2023. Measured RMR (kilocalories per day) was compared to estimated RMR from eight prediction equations using a null hypothesis significance (i.e., a paired t-test) and equivalence (i.e., a two one-sided test) tests. Bland-Altman plots, Pearson correlations and linear regressions were used to evaluate the bias between the measured and predicted RMR values. RESULTS: Measured RMR in adults with DS was 1090 ± 136 kcal/day. Prediction equations overestimated RMR by 8 ± 16% (76 ± 165 kcal/day) to 45 ± 16% (488 ± 165 kcal/day) except for the Bernstein fat-free mass equation which underestimated RMR by 0.2 ± 11.5% (8 ± 123 kcal/day) and was statistically equivalent to measured RMR in our sample (p = 0.027). CONCLUSIONS: The Bernstein fat-free mass equation offers better accuracy in adults with DS than other RMR prediction equations, but the equation needs to be evaluated in larger, more diverse samples of adults with DS.
Journal of intellectual disability research : JIDR, 2025 · doi:10.1111/jir.13215