Most women eat less protein than they need

The commonly quoted figure is around 0.8 grams of protein per kilogram of body weight per day. It is worth knowing what that number is: it is the estimated amount required to prevent deficiency in most healthy adults.

It is a floor, not a target. It was never intended to describe the intake that optimises muscle retention, bone health, recovery or satiety, and the research on those outcomes points considerably higher.

The numbers that actually apply

For general health and preserving muscle with age: roughly 1.2 to 1.6 g/kg per day.

For people doing resistance training: roughly 1.6 to 2.2 g/kg per day. Above about 1.6, additional intake yields diminishing returns for most people, though higher intakes are safe.

For older adults: higher rather than lower, because of anabolic resistance — the same protein dose produces less muscle protein synthesis with age. Guidance for adults over 65 commonly sits at 1.2 to 1.5 g/kg or above.

In pregnancy and lactation: requirements increase substantially, and there is reasonable evidence that standard recommendations underestimate them.

For a 65kg woman doing some resistance training, 1.6 g/kg is around 105g of protein a day. Dietary surveys consistently find intakes well below that, particularly in women, and particularly in women who are dieting — which is exactly when protein needs are highest.

Why it matters more for women

Muscle. Muscle mass declines from the fourth decade and the decline accelerates around menopause. Protein plus resistance training is the combination that resists it; either alone does less. Strength training does more for women than any other exercise.

Bone. Bone is roughly half protein by volume. Higher protein intake is associated with better bone density and lower fracture risk. The long-standing concern that high protein leaches calcium from bone has not survived scrutiny — the increase in urinary calcium is accompanied by increased intestinal absorption. What happens to your bones around menopause.

Satiety. Protein is the most satiating macronutrient. In practice this makes adequate intake one of the more effective interventions for people who feel constantly hungry, particularly in the luteal phase when appetite genuinely rises — the luteal phase.

Iron. Animal protein sources are also the main sources of haem iron, which is absorbed several times more efficiently than the non-haem iron in plants. Low protein intake and low iron status frequently travel together in women — iron deficiency in women.

Distribution matters, a bit

Muscle protein synthesis responds to a per-meal dose rather than a daily total, with the response plateauing somewhere around 25 to 40g of high-quality protein in a meal for most adults.

The practical implication: 100g spread across three or four meals does more than 100g concentrated in dinner. The common pattern — a small breakfast, a light lunch, and most of the day's protein in the evening — is not optimal.

This is a real effect and a second-order one. Getting the daily total up matters more than perfecting the distribution.

Where it comes from

Animal sources — meat, fish, eggs, dairy — are complete proteins with high leucine content, which is the amino acid that most directly triggers muscle protein synthesis.

Plant sources work perfectly well, with two adjustments: total intake generally needs to be somewhat higher because of lower digestibility and less favourable amino acid profiles, and variety matters so that the full amino acid range is covered. Soy, which is a complete protein, is a particularly useful staple. There is no need to combine proteins within a single meal — that idea was abandoned decades ago.

Protein powder is food, not a supplement in any meaningful sense. It is a convenient way to hit a number, nothing more and nothing less.

The underfuelling problem

The other half of this is total energy, and it deserves emphasis because it is common and under-recognised.

Low energy availability — not eating enough to cover both training and basic physiological function — has consequences well beyond performance: suppressed reproductive hormones, reduced bone formation, impaired immune function, altered metabolic rate, and mood effects. In its recognised form it is called relative energy deficiency in sport, and it does not require being an athlete or being underweight.

The most common route to it is undramatic: a diet, plus a new training habit, sustained for months. Adding exercise without adding food creates the deficit.

The clearest signal that you are in it is your cycle. Cycles that lengthen, become irregular or stop are the reproductive axis responding to insufficient energy — how stress affects your cycle and missing periods when you are not pregnant. Other signs: persistent fatigue, frequent illness, stress fractures, poor recovery, feeling cold, and low mood.

Two weeks of honest counting

Most people substantially overestimate their protein intake, because it is genuinely unintuitive — a chicken breast is about 30g, an egg about 6g, a slice of bread about 3g.

Weighing and logging for two weeks is usually enough to establish where you actually are. After that, most people can estimate reasonably from habit and do not need to keep counting.

The more useful long-term measure is not the number itself but what it correlates with: energy, recovery, training quality, hunger, sleep and — the most sensitive indicator of all — what your cycle is doing.

Naked is built to hold those together, so the effect of a change in how you eat shows up where it actually shows up: in energy, in recovery, and in whether your cycle stays regular.