GLP-1 Protein & Macro Calculator

How the calculator works

The math is simple but every coefficient is sourced from a peer-reviewed primary source.

• BMR (Mifflin-St Jeor 1990, PMID 2305711) [1]:
  Male: 10×W(kg) + 6.25×H(cm) − 5×age + 5
  Female: 10×W(kg) + 6.25×H(cm) − 5×age − 161
• TDEE (FAO/WHO/UNU 2001 PAL multipliers) [13]: BMR × {1.2, 1.375, 1.55, 1.725, 1.9} for sedentary, light, moderate, very, and extremely active.
• Caloric deficit (Hall 2011, PMID 21872751) [10]: 500 kcal/day deficit for weight loss yields ~0.45 kg/week at steady state. Real rates are slower due to metabolic adaptation.
• Protein tier selection (see below).
• Per-meal split (Mamerow 2014, PMID 24477298) [5]: even distribution across 3 main meals increased 24-h muscle protein synthesis by ~25% versus skewed.

The protein tier ladder

Five tiers, each anchored on a specific published recommendation:

• 0.8 g/kg/day — the RDA. Sufficient for sedentary adults at maintenance, almost certainly insufficient for anyone losing weight on a GLP-1.
• 1.0-1.2 g/kg/day — PROT-AGE 2013 [2] recommendation for healthy older adults at maintenance.
• 1.2-1.6 g/kg/day — PROT-AGE for disease/exercise, ESPEN 2014 [8] for older adults with disease, and the lower end of the ISSN 2017 [4] range for active individuals.
• 1.6-2.0 g/kg/day — ISSN 2017 [4] recommendation for active individuals, and the Neeland 2024 [9] target for GLP-1 patients.
• 2.0-2.4 g/kg/day — Longland 2016 [3] high arm (added LBM during a 4-week severe deficit + RT), Mettler 2010 [7] LBM preservation in trained athletes during weight loss, and Helms 2014 [6] contest-prep range.

The GLP-1 bump

Patients flagging that they are on (or starting) a GLP-1 receptor agonist get bumped one tier higher than they would otherwise. The reason: the STEP-1 [11] and SURMOUNT-1 [12] body composition substudies show 25-45% of total weight loss on these drugs is lean tissue without protein and resistance training intervention, and the Neeland 2024 [9] review on GLP-1 lean mass mitigation specifically recommends targeting the higher end of the protein range (1.6-2.3 g/kg fat-free mass) for this population. The bump is the clinical translation of that finding.

What this calculator does NOT do

• It does not measure your body fat or lean mass. The protein target is based on total body weight, not fat-free mass. DXA-based fat-free-mass targeting is more precise and is what clinical trials use; for home use, total body weight is an acceptable proxy.
• It does not adjust for kidney disease. Patients with chronic kidney disease (eGFR < 60) should discuss protein intake with their nephrologist before pushing into the higher tiers.
• It does not provide a meal plan. It tells you targets; you and a registered dietitian can build the plan.
• It does not replace a clinical conversation with your prescriber, especially if you are managing diabetes, kidney disease, or any condition that affects nutrition.

Important disclaimer

This calculator is for educational purposes only and does not constitute medical advice or dietary prescription. The published protein recommendations are from healthy adult and older-adult populations and do not directly apply to patients with chronic kidney disease, advanced liver disease, or metabolic disorders. Patients with any of these conditions should consult a registered dietitian or their prescribing clinician before adopting the targets in this tool. Every coefficient was verified against PubMed primary sources by a research subagent on 2026-04-07.

Related tools and research

• Semaglutide and muscle mass loss — the lean tissue loss problem this tool is designed to mitigate
• Loose skin after rapid GLP-1 weight loss — downstream effect of inadequate lean-mass preservation
• What to eat on a GLP-1 — practical food choices for the protein target
• GLP-1 BMI calculator — see your starting BMI and trial endpoint projections
• GLP-1 weight loss calculator — week-by-week trial projections