GLP-1 Protein Calculator
Calculate Your Daily Protein Target
GLP-1 medications suppress appetite, making it harder to hit protein goals. This calculator estimates your optimal daily protein to preserve muscle while losing fat.
Protein Calculator
How to Use the GLP-1 Protein Calculator
Enter your body stats
Input your age, height, and current weight. Choose imperial or metric units.
Choose your GLP-1 phase
Select whether you're actively losing weight or in maintenance mode.
Select your training level
Protein needs often rise with resistance training—tell us how often you lift.
Use the per-meal number
Plan your meals with the per-meal target—spread protein evenly when possible.
Frequently Asked Questions
Common questions about protein on GLP-1 therapy
Why does protein matter on GLP-1 medications?
Muscle can drop during rapid weight loss: Studies of GLP-1 therapies show weight loss includes both fat mass and lean mass. Semaglutide and tirzepatide body composition substudies report measurable lean mass reductions alongside fat loss.
Appetite suppression makes protein harder: GLP-1 users may struggle to eat enough protein because they get full quickly and can experience taste aversions—so a "protein first" approach can help.
Distributing protein helps synthesis: Consensus guidance highlights protein intakes >1.2 g/kg/day, spread across meals, combined with resistance training as a practical approach to preserve lean mass.
How does Glapp calculate your protein target?
Evidence-based protein ranges: We use published expert guidance: general adult baseline (RDA) is ~0.8 g/kg/day. During active weight loss, higher targets like 1.2–1.6 g/kg/day have been proposed. During strength training: 1.2–1.7 g/kg/day.
Adjusted body weight (BMI ≥ 30): Because using actual weight can overestimate protein needs when body fat is high, the calculator defaults to an adjusted weight approach in obesity—aligning with clinical nutrition practice.
Per-meal targets: We show protein per meal because spreading protein out can support muscle protein synthesis better than eating most protein in one meal. Aim for ~25–30g per meal when possible.
How much protein do I need on Ozempic or Wegovy?
During active weight loss on semaglutide (Ozempic, Wegovy), expert guidance suggests 1.2–1.6 g of protein per kg of body weight per day. This is higher than the general RDA to help preserve muscle mass during rapid weight loss.
How much protein do I need on Mounjaro or Zepbound?
The protein recommendations for tirzepatide (Mounjaro, Zepbound) are similar to semaglutide: 1.2–1.6 g/kg/day during weight loss. The SURMOUNT-1 substudy showed about 25% of weight lost was lean mass, making adequate protein especially important.
Why does the calculator use "adjusted weight" for higher BMIs?
Using actual body weight can overestimate protein needs when body fat is high. The calculator uses a clinically established "adjusted body weight" formula (IBW + 25% of excess weight) to provide more accurate targets. You can switch to actual weight if preferred.
Should I spread protein across meals or eat it all at once?
Research suggests spreading protein evenly across meals (e.g., ~25–30g per meal) can improve muscle protein synthesis compared to consuming most protein in one meal. This is why we show a per-meal target.
Do older adults need more protein?
Yes. The PROT-AGE position paper recommends adults 65+ consume at least 1.0–1.2 g/kg/day to maintain lean mass and function—higher if physically active. The calculator automatically adjusts targets for older adults.
What if I have kidney disease?
Severe kidney disease (especially eGFR <30 and not on dialysis) may require different protein targets. If you have kidney disease or have been told to limit protein, please consult your healthcare provider before using these recommendations.
Is there a maximum protein intake I should avoid?
Prolonged intake above ~2 g/kg/day is generally not recommended according to current guidance. The calculator caps recommendations at this level. Higher intakes haven't shown additional benefits for most people.
Data Sources
This calculator uses evidence-based recommendations from the following sources:
- Joint Advisory (ACLM, ASN, OMA, TOS) — Nutritional priorities to support GLP-1 therapy for obesity (protein ranges, adjusted-weight, upper limits)
- Obesity Pillars / International Consensus — Practical recommendations: protein >1.2 g/kg/day distributed across meals + resistance training
- STEP-1 Body Composition Analysis — Semaglutide substudy demonstrating lean mass decreases alongside fat loss
- SURMOUNT-1 DXA Substudy — Tirzepatide body composition: ~75% fat mass and ~25% lean mass of weight lost
- PROT-AGE Position Paper — Recommends 1.0–1.2 g/kg/day for older adults, notes kidney disease exception
- BDA Manual of Dietetic Practice — Adjusted body weight formula: AdjBW = IBW + 0.25×(actual−IBW)
⚠️ Important Medical Disclaimer
This calculator is for informational purposes only and does not constitute medical advice. Always consult with your healthcare provider before making any changes to your medication dosing.
Dosage calculations should be verified by a healthcare professional. Glapp and its contributors assume no liability for medication dosing errors or adverse events.
Off-Label Use Notice: Split dosing features represent off-label use not approved by the FDA. Discuss with your prescriber before implementing.