How much protein do you need per day?

How much protein do I need per day?

The official adult minimum is 0.8 grams of protein per kilogram of body weight per day, which is about 56 g for a 70 kg person. That figure prevents deficiency. Research groups recommend 1.0 to 1.2 g/kg for adults over 65, and higher again during weight loss or regular training.

Key takeaways

0.8 g/kg/day is a floor set to prevent deficiency in healthy adults, not a target for good health.
The PROT-AGE and ESPEN expert groups both recommend at least 1.0 to 1.2 g/kg/day for healthy adults over 65.
Protein needs rise when you are losing weight, because some of the loss otherwise comes from muscle.
Body weight drives the number far more than sex does, which is why a per-kg figure beats a flat 'women need X grams' rule.
Severe kidney disease is the main exception. Those targets are set by a clinician, not by a calculator.

The short answer, and why it is not the whole answer

The Recommended Dietary Allowance for protein is 0.8 grams per kilogram of body weight per day for healthy adults, set by the Institute of Medicine in 2005.¹ For a 70 kg (154 lb) adult that is about 56 g per day.

That number does less than most people assume. The RDA was derived from nitrogen balance studies and answers a narrow question: what is the smallest intake at which almost everyone avoids a deficit? It is a floor designed to prevent deficiency, not a target associated with the best outcomes for muscle, recovery or ageing.

Three groups of people have a well-documented case for eating more than the floor: adults over about 65, people in a calorie deficit, and people training regularly.

Healthy adults, the floor0.8 to 1 g/kg/day
Adults over 651 to 1.2 g/kg/day
Illness, injury, or losing weight1.2 to 1.4 g/kg/day
Training to build or keep muscle1.4 to 2 g/kg/day

The bands run end to end so the tiers read in order. The exact figure each one came from, and who published it, is in the table below.

The numbers, side by side

Who	Recommended intake	Source
Healthy adults, minimum to avoid deficiency	0.8 g/kg/day	Institute of Medicine, 2005
Healthy adults over 65	1.0 to 1.2 g/kg/day	PROT-AGE, 2013 and ESPEN, 2014
Older adults who exercise	1.2 g/kg/day or more	PROT-AGE, 2013
Older adults with acute or chronic illness	1.2 to 1.5 g/kg/day	PROT-AGE, 2013
Building or maintaining muscle while training	1.4 to 2.0 g/kg/day	ISSN position stand, 2017
Severe kidney disease (eGFR under 30, not on dialysis)	Restricted, set individually	PROT-AGE, 2013

The Institute of Medicine also set an Acceptable Macronutrient Distribution Range of 10 to 35 percent of daily calories from protein, and did not set a tolerable upper intake level.

What that looks like in grams

Multiply your body weight in kilograms by the rate. To go from pounds, divide by 2.2 first.

Body weight	0.8 g/kg (minimum)	1.2 g/kg (older adults)	1.6 g/kg (training)
55 kg / 121 lb	44 g	66 g	88 g
70 kg / 154 lb	56 g	84 g	112 g
85 kg / 187 lb	68 g	102 g	136 g
100 kg / 220 lb	80 g	120 g	160 g

Our protein calculator applies the same rates to your weight, age and activity level and shows which recommendation the result came from.

Why the number goes up as you get older

Older muscle responds less strongly to the same amount of protein, an effect usually called anabolic resistance. A dose that triggers muscle protein synthesis comfortably at 25 does less at 70, so the intake required to maintain the same muscle mass is higher.

This is why the PROT-AGE Study Group, reviewing the evidence in 2013, recommended at least 1.0 to 1.2 g/kg/day for people over 65 rather than the general 0.8.² The ESPEN Expert Group reached the same range independently in 2014.³ Both note that the requirement rises further with illness or injury.

The consequence of not meeting it is sarcopenia: the gradual loss of muscle mass and strength that makes stairs harder, falls more likely and recovery slower.

Why the number goes up when you are losing weight

Weight loss is never purely fat loss. Some fraction of the tissue lost is lean mass, and that fraction is larger when protein intake is low. Eating more protein during a deficit shifts the composition of what you lose toward fat, which is the main reason a high protein diet is worth the effort when you are losing weight rather than a way of losing it faster.

This matters more now than it used to, because GLP-1 medications like semaglutide and tirzepatide produce fast, large weight loss. In the SURMOUNT-1 trial of tirzepatide, roughly a quarter of the total weight lost was lean mass. We cover that in detail in protein and muscle loss on GLP-1 medications.

Does timing matter, or just the daily total?

The daily total does most of the work. Beyond that, spreading protein across meals appears to help: the PROT-AGE group suggested distributing intake so that each main meal carries a meaningful dose, rather than eating very little at breakfast and a large amount at dinner.

A practical version of that: aim for roughly 25 to 30 g at each main meal instead of 10 g, 15 g and 70 g. Most people find breakfast is where the shortfall lives.

How to actually hit it

Knowing the number is the easy half. The harder half is knowing where you are against it on an ordinary Tuesday, which is the whole reason protein tracking exists as a category separate from calorie counting.

You do not need to log everything you eat to do this. You need one number per day, compared against one target. Protein Buddy sets the target from your weight, age, activity and whether you are on a GLP-1 medication, then lets you log a meal by photographing it, saying what you ate, scanning a barcode, or typing the grams.

The exception worth naming

People with severe kidney disease are the clear exception to all of the above. PROT-AGE explicitly carves out adults with an estimated GFR below 30 mL/min/1.73 m² who are not on dialysis, who may need to limit protein rather than increase it.

If you have reduced kidney function, are pregnant, or are managing a medical condition that affects protein metabolism, your target is a clinical decision. This article is reference material, not medical advice.