Protein Target Calculator

Why protein matters more than the RDA suggests

The RDA of 0.8 g/kg is a floor — the minimum to prevent nitrogen-balance deficiency in healthy adults. It's a long way from optimal. Phillips and colleagues' 2016 review¹Applied Physiology, Nutrition, and Metabolism · 2016Phillips SM, Chevalier S, Leidy HJ — Protein 'requirements' beyond the RDA: implications for optimizing health situates the optimum for body composition, satiety, and ageing at 1.2–1.6 g/kg. Bray's 2012 JAMA inpatient overfeeding study²JAMA · 2012Bray GA et al. — Effect of dietary protein content on weight gain, energy expenditure, and body composition during overeating demonstrated directly that low-protein groups gained more fat and less lean mass at matched calories. Cermak's 2012 meta-analysis³American Journal of Clinical Nutrition · 2012Cermak NM et al. — Protein supplementation augments the adaptive response of skeletal muscle to resistance-type exercise training: a meta-analysis confirmed protein supplementation augments resistance-training adaptations across populations. Weigle 2005⁴American Journal of Clinical Nutrition · 2005Weigle DS et al. — A high-protein diet induces sustained reductions in appetite, ad libitum caloric intake, and body weight despite compensatory changes in diurnal plasma leptin and ghrelin concentrations showed increasing protein from 15% to 30% triggered a spontaneous 441 kcal/day reduction in ad-libitum intake — protein leverage in action.

Sources: animal vs plant

Animal proteins (eggs, meat, fish, dairy) are complete and have higher leucine content per gram — relevant for muscle protein synthesis. Plant proteins (legumes, soy, seitan) can hit equivalent total-protein targets but typically require 10–20% more grams to match leucine intake, and combining sources is needed to cover all essential amino acids. Both work; animal sources are more efficient per gram.

Distribute across meals

Phillips and Van Loon's 2011 athlete-protein review⁵Journal of Sports Sciences · 2011Phillips SM, Van Loon LJC — Dietary protein for athletes: from requirements to optimum adaptation established that distributed intake (~0.4 g/kg per meal across 3–4 meals) maximizes muscle protein synthesis vs concentrating it all in one meal. For a 70 kg adult at 1.6 g/kg (112 g/day total), that's ~28 g per meal across 4 meals — roughly 4 oz of meat plus a Greek yogurt at each.

Post-GLP-1 muscle preservation

The Linge 2024 Obesity Reviews substudy⁶Obesity Reviews · 2024Linge J et al. — Body composition and cardiometabolic effects of GLP-1 receptor agonists: changes in lean mass documented that 25–40% of total weight lost on semaglutide is lean mass — a sarcopenia risk especially relevant for women and older adults. The Jensen 2024 JAMA Network Open study⁷JAMA Network Open · 2024Jensen SBK et al. — Bone health after exercise alone, GLP-1 receptor agonist treatment, or combination treatment showed GLP-1 monotherapy reduced bone density at hip and spine; exercise prevented this. The protocol when on or coming off a GLP-1: 1.8–2.0 g/kg protein, distributed across small frequent meals (because appetite is suppressed), plus resistance training 3x/week. Non-negotiable.

Supplements when appropriate

Whey protein is the best-studied and most cost-effective supplemental option; casein has slower digestion useful before sleep; plant blends (pea + rice + hemp) approximate complete amino-acid profiles. Most adults can hit 1.6 g/kg from food alone; supplements help when training intensity is high, when post-GLP-1 appetite is low, or when convenience genuinely beats compliance.