Pregnancy nutrition
Eating for two starts later and adds less than the phrase suggests. Here is an estimate for your trimester, built from the equation clinicians actually use.
Your dates stay on this device. Nothing you enter here is saved or sent to Flowy.
Also called pregnancy calorie intake calculator, how many calories when pregnant. Same calculation, one page.
The calculation
The Mifflin-St Jeor equation estimates your basal metabolic rate from age, height and pre-pregnancy weight. Multiplying by an activity factor gives the calories needed to maintain that weight outside pregnancy.
On top of that go the Institute of Medicine additions used in ACOG patient guidance: 340 calories a day in the second trimester and 452 in the third, with roughly 300 more per additional baby. The first trimester adds nothing for most people.
Good to know
A calorie target is one number among several, and not the most important. Folic acid, iodine, iron and vitamin D matter more to outcomes than hitting a daily figure, and steady weight gain across the pregnancy tells you more than any calculation.
First trimester nausea makes eating to a target unrealistic for many people. Eating what stays down is the right approach in that stretch, and appetite generally returns.
If you are tracking intake because eating feels difficult to control, a number from a calculator is unlikely to help. That is worth raising with your midwife.
Common questions
For most people, none in the first trimester, about 340 a day in the second, and about 450 a day in the third. Eating for two from the start is the most persistent piece of bad pregnancy advice going.
Roughly 300 extra calories per additional baby per day on top of the trimester figure, which is why the total for twins lands near 600. Multiple pregnancies need individual advice rather than a formula, so treat this as a starting point for a conversation.
Your pre-pregnancy weight. The Mifflin-St Jeor equation was built on non-pregnant bodies, and the pregnancy addition is applied on top. Entering your current weight double counts the pregnancy.
It lands within a couple of hundred calories for most people and misses badly for some. Equations like this are population averages, and individual metabolic rates vary by 10 percent or more in either direction.
The reference intake in pregnancy is about 1.1 grams per kilogram of body weight per day, which the calculator works out for you. It rises with multiples.
If you started pregnancy underweight or with obesity, have gestational diabetes, are managing hyperemesis, are carrying multiples, or are not gaining weight as expected. A midwife or dietitian can work from your measurements rather than an average.
