How much protein do you need, and are you getting it?

Everyday science · 8 minute read

Protein is on every yoghurt tub and all over your feed. None of it tells you how much you need, or whether a normal day gets you there.

Ask most women if they eat enough protein and they’ll say yes, there’s chicken at dinner. The catch is that if breakfast was toast in the car and lunch was a salad, that chicken was the first real serve of the day, and when a member feels wrecked after a class and can’t see why she isn’t getting stronger, what she ate before dinner is one of the first things our physios ask about. Protein is what your body repairs itself with, and it doesn’t bank spare, so a run of short days leaves less to repair with.

How much you need

Australia’s recommended intake for women is 0.75 g of protein per kilo of body weight a day, about 46 g for an average-sized woman. It’s set to cover basic needs, most of us clear it without trying, and getting stronger takes more.

If you’re lifting, extra protein builds extra muscle up to about 1.6 g per kilo a day, and past that, more protein stops buying you more muscle. Over 65, aim for at least 1.0 to 1.2 g per kilo, more if you’re training.

If you’re around 70 kg, that’s about 53 g a day as a base. Add two strength classes a week and 84 to 112 g is the better aim, and that range of 1.2 to 1.6 g per kilo covers most of our members.

Spread it across the day

The yoghurt tubs leave this part out. Muscle responds meal by meal, and a serve of about 20 to 40 g at a time is what gets the most muscle building out of a meal. That works out at roughly 0.25 g per kilo per meal, every three to four hours. In your 70s muscle gets a bit harder of hearing, and it takes closer to 0.4 g per kilo in one sitting to get the response you’d have had at 30. The study behind that figure was in men, and it’s the best number we have.

In real life that means 25 to 30 g at each main meal. Two eggs on toast with a glass of milk gets you close. A bowl of cereal doesn’t, and nor does a muesli bar eaten standing up.

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Signs you might be short

True deficiency, the kind with muscle wasting and swelling, is uncommon in Australia outside illness and old age. Far more common is a day that keeps you going but leaves nothing over for repair, so Tuesday’s class is still in your legs on Friday. The signs our physios hear about are ordinary: slower to recover from a class that used to leave you fine, and strength that’s gone flat even though you’re turning up. Often the gap is food overall rather than protein on its own, and low iron, poor sleep or a thyroid problem can look the same, so if it lasts more than a few weeks, see your GP and ask about a blood test.

Protein through the life stages

Your 20s and 30s. This is when you build the muscle and bone you’ll draw on later, so if you train, 1.2 to 1.6 g per kilo is the range to aim for.

Pregnancy and breastfeeding. From the second trimester the Australian target rises to 1.0 g per kilo, and to 1.1 g per kilo while you’re feeding, so a 70 kg mum is aiming for 70 to 77 g a day.

Your 40s and 50s. Muscle gets harder to hold onto from here, and the same protein that built muscle at 25 does a little less at 50. The usual training guidance for this stage is 1.2 to 1.6 g per kilo alongside strength work, which is what our Midlife Strength classes are built around.

65 and beyond. The expert recommendation is 1.0 to 1.2 g per kilo a day, at least 1.2 if you’re active, with bigger serves per meal than you needed at 30. Paired with strength and balance work, it protects the muscle that keeps you independent.

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Where the protein is

You don’t need to weigh anything. Most everyday foods fall into a few brackets (rough figures, from the Australian Food Composition Database).

• About 25 to 35 g: a palm-sized piece of cooked chicken, beef or lamb (100 g), a salmon fillet (150 g), a scoop of whey in milk.
• About 15 to 25 g: 2 eggs with a glass of milk, a small tin of tuna, 200 g of high-protein Greek yoghurt, 150 g of firm tofu, a large cup of cooked lentils.

Eggs instead of cereal, or the overnight oats made on Sunday night, sorts out the first meal. For dinner, the salmon and white bean traybake does the maths for you.

When a protein powder earns its place

Food should do most of the work. A powder is for the days you’ve skipped a meal without noticing, or you’ve just finished a class and dinner is hours away. A scoop in milk is about 35 g, a whole meal’s worth. We stock True Protein, and members get 10% off, applied automatically at the front desk. If you’re pregnant, check the label with your midwife first.

If you have kidney disease, diabetes or high blood pressure, check with your doctor before adding protein. In healthy adults, the trials so far found more protein didn’t harm the kidneys over the months they ran, and the only Australian ceiling is a loose one: keep protein to about a quarter of your day’s energy.

Working out your number

1. 1Multiply your weightYour weight in kilos times 1.2 is a sensible daily target if you train, and up to 1.6 if you’re building muscle. Over 65, aim for 1.0 to 1.2, and at least 1.2 if you’re active.
2. 2Split it into mealsDivide by three, or by four if you eat after training. That’s your per-meal number, usually 25 to 35 g.
3. 3Check one ordinary dayTally a normal day against the brackets above, or let a tracking app do it.
4. 4Fix breakfast firstIf one meal is short, it’s nearly always the first one.

The takeaway

Most women who train need more protein than the basic recommendation, and most of us eat it at the wrong end of the day. Aim for 1.2 to 1.6 g per kilo if you train, and get 25 to 30 g into each meal, the first one included.