Want gains? Lift weights and eat 1.6 grams of protein a day, a new study says.

FOR A WHILE, lifter bros insisted on scrambling to pound down their protein shakes within the “magical” 30-minute window after they set down their last weight. Experts then said: Nah, it’s not that important to get your protein that quickly, just get it sometime in the day. Then some other experts opined that lifters are probably consuming too much protein, and that they should cut back. Nobody could agree on how much protein and when.

But now the real wizards of lifting science at McMaster University in Canada have spoken. Their stance, according to a new meta-analysis: Supplementing your resistance workouts with protein is definitely linked to significant gains in muscle strength and size.

Researchers initially analyzed more than 3,000 studies to come up with 49 solid, high-quality studies that involved more than 1,800 people. In their meta-analysis, they discovered that adding in extra protein to the diet of healthy, weight-lifting adults helped build bigger and stronger muscles, regardless of the protein source (steak or powder), when they took it, and whether the lifters were male or female.

But don’t expect to pound tons of protein and see automatic results. The researchers also found that there’s an upper limit of effective protein consumption: About 1.6g of dietary protein per kg of bodyweight per day.

“Protein intake is critical for muscle health, and there is mounting research that suggests the recommended dietary allowance of 0.8g protein per kg per day, is too low,” said study head Robert Morton, a Ph.D. student in the Exercise Metabolism Research Group at McMaster. “We will see more and more research, especially as our populations age, challenging that number.”

In the meantime, here’s a guide to working more protein into your diet, and a guide to the 30 best muscle-building protein foods.