This is a macro calculator built specifically for people on GLP-1 medications (semaglutide, tirzepatide, and similar). The goal is helping you preserve lean mass during rapid weight loss — which standard "calories in / calories out" calculators completely miss.
Published trials show that 25–40% of weight lost on GLP-1 medications can be lean mass (muscle) when protein intake is inadequate. The fix is well-established: higher protein per kilogram of body weight, plus resistance training. But most macro calculators target protein as a percentage of total calories — which means when GLP-1 patients eat fewer calories overall, they also reduce their protein target. That's backwards.
This tool fixes that by setting protein in grams per kilogram of body weight, with a higher default for GLP-1 users (1.8 g/kg vs. 1.6 g/kg standard).
BMR via Mifflin-St Jeor (most accurate general-population formula). TDEE via Harris-Benedict activity multipliers. Protein targets per recommendations from sports nutrition literature and emerging GLP-1 nutrition guidelines. Fat floor at 0.6 g/kg to support hormone function. Calorie floors at 1,200 (women) and 1,500 (men) to prevent metabolic adaptation.
This calculator is educational. GLP-1 medications interact with electrolytes, hydration, gallbladder function, and other systems that an online calculator can't account for. Always work with your prescribing clinician and ideally a registered dietitian, especially in the first 90 days of treatment.
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