Research on protein and training reports intake in grams per kilo of bodyweight per day, not as a share of calories. The International Society of Sports Nutrition position stand gives 1.4 to 2.0 g per kg per day for most people who exercise[1]. A percentage of calories is a different number, and it moves.
Thirty per cent of 2,600 calories is 195 g of protein. At 2,100 calories the same thirty per cent is 158 g, 37 g less, though only the calorie total changed.
Published protein ranges follow bodyweight, not the calorie total.
What the research reports
Each source below gives its range per kilo, of bodyweight or of lean body mass.
| Source | Protein |
|---|---|
| Recommended Dietary Allowance, adults | 0.8 g per kg of bodyweight[4] |
| ISSN position stand, most people who exercise | 1.4 to 2.0 g per kg of bodyweight[1] |
| Meta-analysis of 49 training studies | No further gain in fat-free mass beyond about 1.6 g per kg of bodyweight[2] |
| Trained lifters in an energy deficit | 2.3 to 3.1 g per kg of lean body mass[3] |
At 80 kg, 1.4 to 2.0 g per kg is 112 to 160 g, whether the day holds 2,100 calories or 3,000. It changes only when bodyweight does.
Then fat, then what is left
The Institute of Medicine puts the acceptable range for fat at 20 to 35 per cent of energy for adults[4]. Worked out in that order, protein per kilo first, fat as a share, carbohydrate from what remains, the arithmetic has a useful property.
A change in calories moves carbohydrate and fat. Protein stays where it was set, because it was never a share of the total. The QuietGains starting targets are worked out in the same order.
Per kilo of what?
Most ranges use total bodyweight. The contest preparation review by Helms and colleagues uses lean body mass instead[3]. For someone weighing 100 kg with 20 kg of fat mass, 2.3 g per kg of lean body mass is 184 g, where 2.3 g per kg of bodyweight would be 230 g.
How the sources spread it across a day
- The ISSN reports per-meal doses of 0.25 g of protein per kg of bodyweight, or 20 to 40 g[1].
- It describes those doses as evenly distributed, every 3 to 4 hours, across the day[1].
- The contest preparation review reports three to six meals a day, with 0.4 to 0.5 g per kg of bodyweight in the meals before and after training[3].
Sources
- [1]Jäger R, Kerksick CM, Campbell BI, et al. International Society of Sports Nutrition Position Stand: protein and exercise. Journal of the International Society of Sports Nutrition 14:20, 2017. doi.org/10.1186/s12970-017-0177-8
- [2]Morton RW, Murphy KT, McKellar SR, et al. A systematic review, meta-analysis and meta-regression of the effect of protein supplementation on resistance training-induced gains in muscle mass and strength in healthy adults. British Journal of Sports Medicine 52(6):376-384, 2018. doi.org/10.1136/bjsports-2017-097608
- [3]Helms ER, Aragon AA, Fitschen PJ. Evidence-based recommendations for natural bodybuilding contest preparation: nutrition and supplementation. Journal of the International Society of Sports Nutrition 11:20, 2014. doi.org/10.1186/1550-2783-11-20
- [4]Institute of Medicine. Dietary Reference Intakes for Energy, Carbohydrate, Fiber, Fat, Fatty Acids, Cholesterol, Protein, and Amino Acids. The National Academies Press, Washington, DC, 2005. doi.org/10.17226/10490