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The science behind your number.
A calorie calculator hands you one clean number. These pieces explain where it comes from, where it goes wrong, and what to do about it. Every scientific claim links to the study behind it, and each one is independently fact-checked before it ships.
11 articles · 63 sources linked
Which BMR Formula Should You Use: Mifflin-St Jeor, Katch-McArdle, or Cunningham?
Mifflin-St Jeor, Katch-McArdle, or Cunningham? How the three main BMR formulas differ, which the research backs, and when to use each.
7 sources linked · 5 min read
How to read these
No listicles, no hedging every sentence. Real mechanisms, named studies, then the practical takeaway. If a claim can't be sourced, it doesn't go in.
Start with the formulas piece if you want the foundation, or jump to whatever question brought you here.
Formulas & accuracy
How the equations behind your number actually work, and which one to trust.
Which BMR Formula Should You Use: Mifflin-St Jeor, Katch-McArdle, or Cunningham?
Mifflin-St Jeor, Katch-McArdle, or Cunningham? How the three main BMR formulas differ, which the research backs, and when to use each.
7 sources linked
MacroMentor vs. calculator.net vs. TDEE Calculators: How the Numbers Differ, and Why
How MacroMentor, calculator.net, and tdeecalculator.net reach different numbers from the same inputs, and which choices actually matter.
6 sources linked
NEAT: The ~2,000 kcal/Day Your Activity Dropdown Flattens
Non-exercise activity can vary ~2,000 kcal/day between people and quietly drops when you diet. Why NEAT, not your BMR formula, drives TDEE accuracy.
5 sources linked
Metabolism & your body
Why two people the same size can burn different amounts, and what really moves the needle.
Does Ethnicity Affect Your BMR? The Research Behind the Adjustment
Does ancestry change your basal metabolic rate? What the studies show, why the effect is small, and how MacroMentor handles it honestly.
9 sources linked
Cold-Adapted Metabolism: The Few Percent That Doesn't Save You
Circumpolar populations run a higher resting burn from cold adaptation, a few percent. Why that edge still loses to lifestyle and diet.
7 sources linked
Your Metabolism Doesn't Fall Off a Cliff at 40
A 2021 Science study found metabolism is stable from 20 to 60, not sliding from your thirties. What actually changes with age, and why 40 feels slower.
3 sources linked
Dieting safely
Deficits, floors, and breaks. The guardrails that keep a plan liveable.
The 1,200-Calorie Floor: Why a Calorie Calculator Won't Go Below 1,200 Calories
Where the 1,200-calorie minimum comes from, what the guidelines actually say, and why a calculator should warn you before going lower.
5 sources linked
Refeed Days and Diet Breaks: A Simple, Calculator-Backed Guide
What refeed days and diet breaks do to metabolism, what the trials actually found, and a simple cadence backed by the calculator.
10 sources linked
Beyond calories
What a calorie count misses: micronutrients, where your weight sits, and more.
Why a Macro Calculator Should Flag Iron, Vitamin D, and Waist Circumference, Not Just Calories
Calorie counts miss iron, vitamin D, and where your weight sits. Why a good calculator flags micronutrients and waist-to-height ratio too.
5 sources linked
Why BMI Lies, and Lies Differently Depending on Your Ancestry
BMI misreads body fat differently by ancestry, and the WHO uses lower Asian cutoffs for it. Why a tape measure beats the number on the chart.
6 sources linked
Quick answers
Short, sourced answers to the questions that sit just under the number.