Protein Intake Calculator — Grams Per Day, Done Honestly

The number the calculator handed you is a range, not a commandment — land inside it most days and you’re doing the thing that matters. Below: where the numbers come from, what they look like as actual food, and how I split mine up, so the range stops being a screen number and starts being dinner.

Why protein is the macro I set first

When I plan a day of eating — mine, or one of my meal plans — protein gets locked in first. Carbs and fat get arranged around it. Three plain reasons for that.

• It’s the building material. Muscle is protein. You can train hard and sleep like a king, but if the raw material isn’t on the plate, there’s nothing to build with. Carbs and fat are fuel; protein is the lumber.
• It protects muscle when you cut. In a deficit, your body will happily break down muscle along with fat. Enough protein, plus lifting, tells it to leave the muscle alone. Every stage cut I did back in Sweden ran on this one principle.
• It keeps you full. Gram for gram, protein is the most satisfying thing you can eat. Cuts get easier the day you stop treating it as an afterthought.

Fat has a floor, and carbs earn their place around training — but neither needs to be exact. Protein is the one worth measuring.

The real numbers, from real research

The best single piece of evidence we have is a 2018 meta-analysis by Morton and colleagues in the British Journal of Sports Medicine. They pooled 49 studies of people lifting weights and found that gains in lean mass plateaued at about 1.6 g of protein per kilogram of bodyweight per day. Past that point, extra protein didn’t build extra muscle for most people.

“Most people” is doing some quiet work in that sentence. The confidence interval in the same analysis stretched up to 2.2 g/kg — some lifters kept benefiting well above 1.6. And the picture shifts with your situation:

• Maintaining or bulking, natural: 1.6–2.2 g/kg covers you. The bottom of the range is where the science says most gains live; the top is cheap insurance.
• Cutting hard: the International Society of Sports Nutrition’s position stand puts lean, trained people dieting at 2.3–3.1 g/kg of fat-free mass. In plain bodyweight terms, 2.2 g/kg and up is a sensible target. Muscle you keep in a deficit is muscle you never have to rebuild.
• Enhanced: TRT or anything heavier raises the rate at which your body can build muscle, and the demand for raw material rises with it. Nobody’s funding a meta-analysis on enhanced lifters, so this one is coaching practice rather than pooled trials: roughly 2.2–3 g/kg. I’ve been on TRT since 35, and I eat at the top end. The gear doesn’t excuse you from the fork — it makes the fork matter more.

Grams per kilo vs grams per pound — sort the units out first

Half the protein arguments online are two unit systems talking past each other. Research is written in grams per kilogram. American gym culture talks in grams per pound. A kilogram is 2.2 pounds, so:

• 1.6 g/kg ≈ 0.7 g per pound of bodyweight
• 2.2 g/kg = 1 g per pound, exactly

The old gym rule of “a gram per pound” turns out not to be bro science after all. It’s the very top of the evidence-based range — generous, not crazy, and a fine default when you’re cutting.

How to split it across the day

Your daily total does most of the heavy lifting. Distribution is the fine-tuning — worth getting roughly right, not worth losing sleep over.

Each feeding of about 0.25–0.4 g/kg (25–40 g for most men) pushes muscle protein synthesis close to its ceiling. Spread your total across 3–5 feeds and you hit that ceiling several times a day instead of once.

Over 50, the dose goes up

Here’s the part most calculators skip, and the reason ours asks your age. As we get older, muscle responds less to a given dose of protein — researchers call it anabolic resistance. Moore and colleagues showed it cleanly in 2015: younger men maxed out muscle protein synthesis at about 0.24 g/kg per meal, older men needed about 0.40 g/kg. Same meal, weaker signal — so the meal has to be bigger.

I’m 40, on TRT since 35, and most of the men I cook for are past that line — so I already build my meals around 40 g and up. I wrote the whole picture up in how much protein you need to build muscle after 50 if you’re in the same decade.

What 40 g of protein actually looks like

Grams are abstract. Plates aren’t. Here’s what one solid 40-gram feeding looks like in real food:

That table’s quiet message: 180 g a day is four or five of those portions. Real food, completely doable. If you want the chicken math in full detail — raw vs cooked, sizes, the lot — I broke it down in how much protein is in a chicken breast.

How I split my own day

For what it’s worth, here’s mine. I’m 40, on TRT, and usually holding a slight cut, so I sit at the top of the range and split it into four feeds of 45–50 g each:

1. Breakfast: skyr with whey stirred in, plus a couple of eggs — an old Stockholm habit that turned out to be perfect macro engineering.
2. Lunch: chicken breast over rice, some kind of vegetable I won’t pretend is the star.
3. Dinner: beef or fish, the biggest and slowest meal of the day, eaten with my family like a human being.
4. Evening: Greek yogurt or cottage cheese before bed — casein does its slow work overnight.

Nothing clever. Four solid doses, each big enough to matter at my age. That’s the whole system.

The kidney question, answered straight

You’ve heard that high protein wrecks your kidneys. Fair question — I’d rather you ask it than quietly worry.

For healthy kidneys, the evidence says no. Devries and colleagues pooled the randomized trials in a 2018 meta-analysis in the Journal of Nutrition and found that higher-protein diets caused no adverse change in kidney function (measured by GFR) compared with lower-protein diets in healthy adults. The scare came from studies of people whose kidneys were already sick, walked backwards onto everyone else.

That last part is the honest caveat: if you have kidney disease, reduced kidney function, or anything on your bloodwork your doctor has flagged, protein intake genuinely is a medical conversation. Have it with them, not with a calculator.