How to start.
-
01
Do your own math
Multiply your weight in kilos by 1.6. At 62 kg that's 100 grams. At 80 kg it's 128. Use your number, not the round one.
-
02
Anchor each meal
Put 25 to 30 grams in every meal. Three or four meals clears the threshold. Backloading the whole day into dinner probably won't.
-
03
Lift, or don't bother
The protein effect sits on top of resistance training, not instead of it. Without lifting you're just buying expensive food.
-
04
Count for three days
Log everything for three days, once. Almost nobody guesses their intake correctly, and you only need to learn your gap once.
Why it works.
-
Muscle growth
Pooling 49 trials and 1,863 people, protein-supported resistance training raised fat-free mass, with gains plateauing at about 1.62 g/kg/day (95% CI 1.03 to 2.20).
-
Strength
The same 49-trial meta-analysis found protein supplementation added a mean 2.49 kg to one-rep-max strength (95% CI 0.64 to 4.33) and 0.30 kg of fat-free mass over the control arms.
-
Lean mass retention
In 40 young men run at a 40 percent energy deficit for 4 weeks, 2.4 g/kg/day gained 1.2 kg lean mass and lost 4.8 kg fat, versus 0.1 kg and 3.5 kg at 1.2 g/kg/day.
Longland et al., 2016, American Journal of Clinical Nutrition
-
Satiety
A review of acute feeding trials found higher-protein meals produced greater perceived fullness and elevated satiety hormones, with roughly 25 to 30 g of protein per meal cited as the working threshold.
Who swears by it.
John's take.
A hundred grams is a marketing number. It’s round, it fits in a headline, and it has nothing to do with your body. The actual finding from Morton’s 49 trials is 1.62 grams per kilo of bodyweight, which happens to land on 100 grams only if you weigh about 62 kilos. If you’re an 80 kg man reading a 100 gram target and feeling like you’ve won, you’re 28 grams short. If you’re a 55 kg woman, 100 grams may be more than you need and you’re forcing down chicken for nothing. Same headline, opposite errors.
What I’d push back on harder is the size of the prize. The pooled advantage in Morton was 0.30 kg of fat-free mass and 2.49 kg on a one-rep max. That’s real, it replicated across 1,863 people, and it is also modest. Protein is not a lever that transforms you. It’s a lever that makes months of lifting count for slightly more than they otherwise would, and the effect shrank with age, which is the opposite of what the supplement aisle implies. The one place it clearly punches above its weight is a deficit: Longland’s group held onto lean mass while cutting fat hard, though at 2.4 g/kg with six training days a week under a 40 percent deficit, which is not a normal life.
The practical thing that made it stick for me was giving up on tracking and using the 25 to 30 gram threshold instead. Every meal gets an anchor, and the day takes care of itself. This is also where the eating-window habits start to fight you: compress to eight hours and you’ve got two or three meals to land the whole target, which is exactly how people end up losing muscle while congratulating themselves on fasting. Pick the fight you actually want. If it’s muscle, protein wins and the clock loses.
Common questions.
How much protein per day should I eat?
About 1.6 g per kg of bodyweight. Morton's meta-analysis of 49 trials put the plateau for muscle gain at roughly 1.62 g/kg/day, with the confidence interval running to 2.20. Eating far past that showed no extra muscle in pooled data. Do the multiplication for your own weight instead of copying a round number.
Is 100 grams of protein a day enough?
It depends entirely on what you weigh. A hundred grams is roughly 1.6 g/kg for a 62 kg adult, so it hits the plateau exactly. At 80 kg, 1.6 g/kg is closer to 128 grams and 100 leaves you short. Treat 100 g as a floor for most adults, and as plenty if you're small.
Does eating more protein actually build muscle?
Yes, but modestly, and only alongside lifting. The pooled advantage across Morton's trials was 0.30 kg of fat-free mass and 2.49 kg on one-rep max, accumulated over months. The protein effect exists on top of resistance training, not instead of it, and effect sizes shrank with age. Protein without training is the most common mistake.
How much protein per meal do I need?
Roughly 25 to 30 grams, which is the working threshold cited in Leidy's review of acute feeding trials. Higher-protein meals in those trials produced greater fullness and elevated satiety hormones. Spreading 100 grams across three or four meals clears that threshold at each one. Saving it all for dinner may not.
Do I need 2.4 g/kg like the studies use?
Almost certainly not. Longland's 2.4 g/kg result came from young men training six days a week under a 40 percent energy deficit for four weeks, which is an extreme protocol built to stress-test lean mass retention. It doesn't show that a normal person under normal conditions needs anything close to that.
Is high protein bad for your kidneys?
If you have chronic kidney disease or you're on dialysis, your protein target is a clinical decision and should be set by your clinician, not by a general fitness number off the internet. That's the group where intake genuinely needs managing. Bring the question to the person who has your bloodwork rather than to a habit page.