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Pregnancy, third trimester: calorie and protein needs

The third trimester carries the largest published energy and protein increments of pregnancy — roughly 500 kcal and 28 g of protein a day above the pre-pregnancy requirement — at exactly the point when eating a large meal is least comfortable.

These are population averages, not a plan for you. Energy and protein needs in pregnancy, third trimester are individualised by a midwife, doctor or registered dietitian who knows your history, your measurements and your blood work. Do not use this page to decide to eat more or less than you have been told to.

Pregnancy and afterWomenReference age 30

This is the stage where the arithmetic and the physical reality pull in opposite directions. The additional energy requirement EFSA publishes for the third trimester is around 500 kcal a day, and the protein increment is about 28 g. At the same time the uterus is pressing on the stomach, reflux is common and large meals are unappealing. The practical answer most maternity dietitians land on is more eating occasions rather than bigger ones.

It is worth being explicit about what the 500 kcal is for. It is not all fetal growth. A substantial share is the extra work of carrying and moving more mass, the metabolic cost of the placenta, and the maternal tissue that supports the last weeks. That is also why the figure is a population average: someone whose activity has dropped to almost nothing in late pregnancy is not spending it the same way as someone still working on their feet.

The other thing this stage changes is the value of a food diary. In the first trimester a diary mostly tells you about nausea. In the third it can show whether the protein increment is actually landing, because 28 g a day is large enough to see in a week of records and small enough to miss completely if you are eating in six small pieces.

The adjustment for this stage

About +500 kcal a day on top of the pre-pregnancy requirement.

PAL 1.4 is the sedentary/low-activity level. Late pregnancy often drags real activity down toward this level even for people who were more active before.

Source: EFSA Dietary Reference Values — energy, protein and micronutrients (European Food Safety Authority) · checked 2026-09-02

The equation this page uses

BMR (men)   = 10 × weight(kg) + 6.25 × height(cm) − 5 × age + 5
BMR (women) = 10 × weight(kg) + 6.25 × height(cm) − 5 × age − 161

Daily target = BMR × 1.40 + 500

Worked through for the middle row of the table below: a woman of 80 kg and 168 cm at age 30 has a Mifflin-St Jeor BMR of about 1 539 kcal. Multiplied by PAL 1.40 that is 2 155 kcal, and adding the 500 kcal increment for this stage gives 2 655 kcal a day.

Worked example: by height and weight

Worked example: how age moves it

What changes if your activity is different

Protein for this stage

EFSA adds roughly 28 g of protein a day in the third trimester. That is the largest protein increment of any life stage on this site — about a chicken breast, or a tin of fish plus a yoghurt.

Source: EFSA Dietary Reference Values — energy, protein and micronutrients (European Food Safety Authority) · checked 2026-09-02

Your own numbers

The nutrients that matter most here

• Iron. Fetal iron stores are loaded largely in the third trimester, which is why maternal iron status is checked in late pregnancy in most maternity systems.
• Calcium. Most of the fetal skeleton is mineralised in the last weeks, drawing on maternal supply and increased absorption.
• Protein. The 28 g/day increment is not an optional extra: it is the largest of the three trimesters because this is when fetal mass is added fastest.
• Vitamin D. Continues to matter for the calcium handling above, and northern winters remain the limiting factor.
• Fluid. Plasma volume is at its peak and heat tolerance is lower. Thirst is a workable guide for most people; your maternity team will tell you if it is not for you.

Source: EFSA Dietary Reference Values — energy, protein and micronutrients (European Food Safety Authority) · checked 2026-09-02

Nutrient reference values are population figures. This page never tells you to take a supplement or how much of one to take — that is a decision for a clinician who can see your blood work and your medicines.

What to actually do

• Split the day into more, smaller eating occasions rather than three large ones.
• Anchor two or three of them with a protein source, because the 28 g increment is hard to hit accidentally.
• Keep fluids visible and within reach; thirst signals are easy to ignore when you are uncomfortable.
• Raise anything unusual — swelling, headaches, reduced movements — with your midwife immediately rather than looking it up.

Frequently asked questions

Other life stages

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