Most pregnant women don’t need any extra calories during the first trimester. In the second trimester, you need about 340 additional calories per day, and in the third trimester, about 450 extra. These numbers are added on top of your normal pre-pregnancy intake, which for most women falls somewhere between 1,800 and 2,400 calories depending on age, height, and activity level.
Calorie Needs by Trimester
The idea that you’re “eating for two” from the moment you get a positive test is one of the most persistent misconceptions about pregnancy. Your body is remarkably efficient in early pregnancy, and the growing embryo is tiny. No additional calories are needed in the first trimester for most women.
The math changes in the second trimester, when fetal growth accelerates and your body builds more blood volume, breast tissue, and placental support. That’s when an extra 340 calories a day becomes necessary. By the third trimester, when the baby is gaining the most weight and your metabolism is running roughly 19% higher than it was before pregnancy, you need about 450 extra calories daily.
To put those numbers in perspective: 340 calories is an apple with two tablespoons of peanut butter (about 304 calories) plus a small handful of nuts. Or a smoothie made with yogurt, frozen fruit, and a banana (around 320 calories). You’re not adding a whole extra meal. You’re adding one or two solid snacks.
How Pre-Pregnancy Weight Changes the Numbers
These general calorie increases assume a normal pre-pregnancy BMI (18.5 to 24.9). If you started pregnancy at a higher weight, the recommendations shift. Women who begin pregnancy with a BMI of 30 or above typically need only an additional 200 calories per day in the second trimester and 400 in the third, slightly less than the standard guideline. The first trimester stays the same: no extra calories needed.
The reason for the difference ties directly to weight gain targets. The CDC breaks these out by BMI category:
- Underweight (BMI below 18.5): 28 to 40 pounds total gain
- Normal weight (BMI 18.5 to 24.9): 25 to 35 pounds
- Overweight (BMI 25.0 to 29.9): 15 to 25 pounds
- Obese (BMI 30.0 to 39.9): 11 to 20 pounds
If you’re gaining weight faster than expected, small adjustments to portion sizes and snacking habits can help you stay on track. Losing weight during pregnancy is not recommended, even for women who start at a higher BMI.
Twin and Multiple Pregnancies
Carrying twins changes the equation significantly. After the 20th week of pregnancy, some programs recommend an additional 1,000 calories per day above your non-pregnant baseline, roughly 500 extra per baby. Your metabolic rate in the third trimester climbs an additional 10% beyond what it would with a single baby.
In practice, guidance for twin pregnancies varies widely. Some women report being told to add 300 to 500 extra calories, while others are advised to add closer to 600 to 1,500. The right number depends on your starting weight, how many babies you’re carrying, and how your weight gain is tracking. This is one area where individualized guidance from a provider or dietitian is especially useful.
What to Eat With Those Extra Calories
The quality of those additional calories matters as much as the quantity. Your protein needs increase throughout pregnancy, rising to roughly 1.2 grams per kilogram of body weight in early pregnancy and 1.52 grams per kilogram in late pregnancy. For a 150-pound woman, that’s about 82 to 103 grams of protein per day. Your carbohydrate needs also rise: a pregnant woman needs at least 135 grams of carbohydrates daily, up from 100 grams for non-pregnant women, because the fetal brain depends heavily on glucose.
Some examples of nutrient-dense snacks that hit the 300-calorie mark:
- Fruit and cheese kabobs: 2 oz low-fat cheese, half a cup of strawberries, and 25 grapes with a small container of yogurt for dipping (305 calories)
- Apple slices with peanut butter: one apple and 2 tablespoons of peanut butter (304 calories)
- Hummus wrap: half a cup of hummus with a whole grain tortilla and half a cup of pea pods (307 calories)
- Blueberry peach smoothie: yogurt, frozen blueberries, frozen peaches, a banana, and a splash of milk (320 calories)
Fat intake should stay within 20 to 35% of your total daily calories, with particular attention to omega-3 fatty acids from sources like salmon, walnuts, and flaxseed.
Risks of Eating Too Much or Too Little
Gaining too much weight during pregnancy is linked to a cluster of complications. A large study found that excessive weight gain nearly tripled the odds of needing a cesarean section or assisted delivery and increased the risk of pregnancy-related high blood pressure almost sixfold. Babies born to mothers with excessive weight gain were nearly seven times more likely to weigh over 4,500 grams (about 9 pounds, 14 ounces) at birth, which raises the risk of birth injuries and NICU admission. Long-term, both mother and child face higher odds of obesity later in life.
Too few calories carries its own risks. Insufficient weight gain during pregnancy is associated with low birth weight and babies measuring small for gestational age, with roughly 64% higher odds compared to women who gain within the recommended range. Low birth weight babies face more health challenges in their first weeks and may have developmental consequences that extend beyond infancy.
The practical takeaway: pregnancy is not the time for dieting, but it’s also not the time for unchecked eating. Tracking your weight gain every few weeks against the recommended range for your BMI category gives you a simple, reliable way to know if your calorie intake is in the right ballpark without counting every bite.