Protein requirements across a lifetime

The general recommendation of around 0.8 grams per kilogram is a population reference for healthy sedentary adults, set to prevent deficiency with a margin.

It is not an optimal figure and it does not apply across circumstances.

The rough map

Infants and young children. High per kilogram, falling through childhood. Requirements are set on growth rather than maintenance.

Plant-based children generally meet requirements where energy intake is adequate, and energy is the more common limiting factor.

Adolescents. Elevated during the growth spurt, alongside substantially increased energy, iron and calcium needs.

Healthy sedentary adults. Around 0.8 grams per kilogram, plus the modest upward adjustment for plant protein — something in the region of 0.9 to 1.0.

Adults doing regular resistance training. 1.6 to 2.2 grams per kilogram, toward the upper end for plant protein.

Endurance athletes. 1.2 to 1.6 or higher depending on volume.

Adults in an energy deficit. Higher again, commonly cited at 2.0 to 2.4 for athletes losing weight, to preserve lean mass.

Pregnancy. Increased, particularly in the later stages.

Breastfeeding. Increased further.

Older adults. Commonly recommended at 1.0 to 1.2, and higher for those who are ill or doing resistance training, because of anabolic resistance.

Illness, injury and recovery from surgery. Substantially increased, and this is frequently the period when intake falls because appetite does.

The plant adjustment, restated

A modest upward adjustment of roughly ten to twenty percent accounts for lower digestibility and amino acid profile.

The practical version: use the upper end of whatever range applies, and include soy foods and varied legumes.

Per meal rather than per day

Distribution matters modestly and matters more with age.

The synthesis response saturates at a dose, and the saturating dose rises with age.

Practically: aim for a meaningful protein source at every meal, with older adults aiming for a larger dose per meal — around 25 to 30 grams — rather than spreading the same total more thinly.

The circumstances that raise requirements and get missed

Recovery from illness or injury, where tissue repair requires substrate and where appetite is frequently poor.

This is one of the more consequential gaps. Someone recovering from surgery or a fracture, eating less because they feel unwell, is in the situation where protein matters most and intake is lowest.

Burns and significant wounds, where requirements are substantially elevated and managed clinically.

Some chronic conditions, where requirements are altered in either direction.

Weight loss at any age, where higher protein preserves lean mass.

Immobility, where muscle loss is rapid and where protein and, where possible, loading both matter.

The circumstances that lower them

Kidney disease, where protein restriction is sometimes advised.

This should be managed by a renal dietitian rather than self-directed, since inadequate protein in kidney disease causes its own problems.

Note that there is interest in plant protein specifically in kidney disease, with some evidence suggesting it may be better tolerated than animal protein, and this is an area for specialist advice rather than general guidance.

Certain metabolic conditions, managed clinically.

How to know whether you are getting enough

Rather than assuming.

Track for a few days. Most people who believe they are getting enough have never counted, and the estimate is frequently wrong in either direction.

Weekdays and a weekend, since intake differs.

Look at the signs. Poor recovery, hair thinning, slow wound healing, frequent illness, persistent hunger, and loss of muscle despite training.

These are non-specific and worth investigating rather than assuming.

Check the structure. Is there a substantial protein source at every meal, or only at dinner? That single question identifies most shortfalls.

The proportion point

Protein receives more attention in plant-based discussion than it warrants for most people, and less than it warrants for a few.

Healthy sedentary adults eating varied plant food with adequate energy generally get enough without thinking about it.

Athletes, older adults, adolescents, pregnant women and anyone recovering from illness need to think about it deliberately.

The failure mode is treating everyone as the first group.

The single most useful habit

A protein source at every meal.

Not a number to calculate, not a supplement to buy. Legumes, tofu, tempeh, soy milk, nuts or seeds at breakfast, lunch and dinner.

That structure meets requirements for most people in most circumstances, and it is where nearly all shortfalls originate.

General information rather than individual advice. Anyone with kidney disease, a metabolic condition, or who is pregnant, recovering from surgery or feeding a child should consult a registered dietitian.