Articles & guides
Evidence-based writing on metabolism, energy balance and the science behind your numbers.
Every article here is written by Rahul Kumar and fact-checked against peer-reviewed research, with sources linked at the end of each piece rather than left as unsupported claims. Coverage spans the Mifflin-St Jeor equation itself, how it compares to alternatives like Harris-Benedict and Katch-McArdle, and the practical side of using a calorie or macro number day to day.
New pieces are added as research changes or as readers ask about a gap in the existing guides. If a formula or a claim on this site doesn't match what you've read elsewhere, the Sources section at the end of each article is where to check the original study.
FundamentalsHow Big Should Your Calorie Deficit Be?
Too big a deficit stalls progress through fatigue and muscle loss. Too small feels invisible. Here's how to size yours based on real research, not guesswork.
FundamentalsMacro Split by Goal: How to Set Protein, Carbs, and Fat for Cut, Maintain, or Bulk
Total calories decide the scale. But your protein, carb, and fat split shapes hunger, muscle retention, and training performance. Here's how to set it by goal.
FundamentalsHow Much Protein Do You Need? The Research
The RDA (0.8g/kg) is a deficiency floor, not a target. Here's what ISSN's position stand and dose-response meta-analyses actually say about protein and muscle.
FundamentalsIdeal Body Weight Formulas: History Explained
IBW formulas weren't built to tell you your best weight. They were built for drug dosing in the 1960s-80s. Here's why that origin matters for how you use them today.
FundamentalsLean Body Mass: Why It Beats Scale Weight
Two people can lose the same 5kg with very different outcomes underneath. Here's why tracking lean body mass, not just scale weight, shows what's really happening.
FundamentalsMifflin-St Jeor vs. Katch-McArdle: Which BMR Formula Is Actually Right for You?
Most weight loss plateaus trace back to the wrong baseline number. See how Mifflin-St Jeor and Katch-McArdle compare by body type, plus a real worked example of how a bad body fat reading breaks a deficit.
FundamentalsMifflin-St Jeor for Older Adults: How Accurate Is It After Age 60?
Metabolism shifts after 60 — sarcopenia, hormones, and organ changes all move the number. Here's how Mifflin-St Jeor holds up for seniors, where it falls short, and how to set safe targets.
FundamentalsMifflin-St Jeor for Athletes: How Accurate Is It for Active People?
Athletes carry more lean mass than the average person Mifflin-St Jeor was built on — so how far off does the formula run? Here's the real underestimation range, and how to adjust for it.
FundamentalsHow Accurate Are Fitness Trackers for Calories Burned? (And What to Do Instead)
A hard workout says 612 calories burned on your watch. The heart rate is probably right — the calorie number almost certainly isn't. Here's why wearables miss by 20-90%, and what to track instead.
FundamentalsThe Biggest Loser Metabolism Study: What Science Really Says About “Metabolic Damage”
Contestants' resting metabolic rate stayed roughly 500 calories below predicted, even 6 years later. Here's what the study actually found — and why “metabolic damage” isn't the right way to describe it.
FundamentalsIs the Mifflin-St Jeor Equation Still Accurate in 2026? What Recent Research Shows
The 1990 formula hasn't changed, but the research testing it has. Here's what 2023-2025 studies actually found about Mifflin-St Jeor's accuracy — including the parts most comparison articles leave out.
FundamentalsHarris-Benedict vs. Mifflin-St Jeor: What the Research Actually Shows
Both formulas estimate BMR from the same basic stats, but they don't agree — and the research on which is more accurate gets more nuanced once you factor in age and body weight. Here's what the studies actually found.
FundamentalsWhat Is BMR (Basal Metabolic Rate)?
BMR is the number of calories your body burns at complete rest — the energy cost of simply being alive. Here's exactly what it means, the Mifflin-St Jeor formula to calculate it, and how it differs from RMR and TDEE.
FundamentalsBMR vs. TDEE Explained: What's the Difference and Which One Should You Use?
BMR is the calories you burn at complete rest; TDEE is your BMR plus everything else you do in a day. Here's how they differ, how to go from one to the other, and the #1 mistake people make: double-counting exercise calories.
FundamentalsWhat Is the Mifflin-St Jeor Equation? (Formula Explained)
The Mifflin-St Jeor equation is the formula most doctors and dietitians consider the gold standard for estimating BMR. Here's its history, the exact formula, and two fully worked examples.