The Larderlab Macro Calculator

Where the 1.6g/kg target comes from

The most-cited target for adults who resistance-train, 1.6 grams of protein per kilogram of bodyweight per day, comes from Morton et al. 2018 (Br J Sports Med), a meta-analysis of 49 studies covering 1,863 participants. The meta-analysis measured protein intake against lean mass gains across a wide range of training protocols and found the dose-response curve flattens at approximately 1.6 g/kg/day. Higher intakes (up to 2.2 g/kg) showed diminishing returns; lower intakes (≤1.2 g/kg) consistently underperformed on lean mass retention.

For an 80kg (176 lb) lifter, 1.6 g/kg = 128 grams of protein per day. Split across three meals, that's ~43g per meal, about 150g of cooked chicken breast, or 300g of Greek yogurt, or two scoops of whey.

Why four ranges, not one

The spread between the RDA (0.8 g/kg) and the ISSN ceiling (2.0 g/kg) is 2.5×. The four ranges answer four different questions. The RDA is the minimum to prevent deficiency in sedentary adults. Phillips 2017 is the target for senior adults preserving muscle. Morton 2018 is the target for resistance-trained adults building or maintaining lean mass. ISSN 2.0 g/kg is the upper practical limit during aggressive cutting phases. Each range applies to a specific reader.

How to hit the target economically

The cost chart above sorts 12 protein sources by $/gram. Whey concentrate wins on a pure $/g basis (~$0.015-0.020/g) but nobody wants to get 100% of their protein from powder. The practical stack for hitting 150g of protein at $5/day: 1 scoop whey + 3 whole eggs + 200g chicken thighs + 2 cups Greek yogurt. That's ~130g of protein at ~$4.20, with the remaining 20g covered by milk and incidental protein in carb sources.

For budget-constrained readers, this is the path. For taste-maximizing readers, shift the budget toward chicken thighs, salmon, and grass-fed beef, which are 2-4× the cost per gram but dominate on the palatability side of the trade.

What the calculator assumes

• BMR is estimated at 22 kcal/kg of bodyweight, a simplified stand-in for Mifflin-St Jeor when age and sex aren't provided. For precision to ±100 kcal, use a full Mifflin-St Jeor calculator and take our fat/carb split off that TDEE.
• Cut deficit is 500 kcal/day (~1 lb/week). Cuts under ~15% body fat require smaller deficits to preserve muscle; cuts above 20% body fat tolerate larger deficits.
• Fat floor is 0.9 g/kg to support hormonal health (Volek 1997; ISSN position on dietary fat). Below 0.6 g/kg for extended periods correlates with lower testosterone in men.
• Carbs fill the remainder after protein and fat. For readers doing high-volume endurance work, lean toward the top of the carb range; for sedentary readers, lean lower.