During the second trimester of pregnancy, you need about 340 extra calories per day beyond what you normally eat. That’s roughly the equivalent of one to two additional snacks, not the “eating for two” overhaul many people expect. The number comes from guidelines by the American College of Obstetricians and Gynecologists, and it reflects the real energy demands of a growing baby, expanding blood volume, and your body’s rising metabolism.
Why 340 Calories, Specifically
Your body’s resting metabolic rate, the energy you burn just by existing, increases steadily throughout pregnancy at a rate of about 11 extra calories per week of gestation. By the middle of your second trimester, that adds up. Your body is building new tissue, maintaining a larger blood supply, and depositing fat stores that will fuel later stages of pregnancy and breastfeeding. All of that takes energy beyond what you’d normally need.
The 340-calorie figure accounts for both the increase in daily energy expenditure and the energy your body stores in new tissue. It’s a step up from the first trimester, when most people don’t need any extra calories at all, and a step below the third trimester, when the recommendation jumps to about 450 extra calories per day as the baby gains weight rapidly.
How the Number Changes for Twins
If you’re carrying multiples, the math is different. Brigham and Women’s Hospital recommends adding 340 calories per baby during the second trimester. That means 680 extra calories a day for twins and 1,020 for triplets. These pregnancies also tend to require earlier and more aggressive nutritional attention, with an extra 300 calories per baby starting in the first trimester rather than waiting until the second.
If You Exercise Regularly
The 340-calorie guideline assumes a typical activity level. If you’re exercising during pregnancy, you’ll likely need closer to 350 to 400 extra calories per day to compensate for the additional energy you burn during workouts. The exact amount depends on the type, intensity, and duration of your activity, but the general principle is straightforward: don’t try to create a calorie deficit while pregnant, and fuel your movement on top of your baseline pregnancy needs.
What 340 Calories Actually Looks Like
The practical reality of 340 calories is surprisingly modest. It’s a yogurt smoothie with berries and nut butter, or a couple of hard-boiled eggs with a piece of fruit. It is not a second dinner. That disconnect between perception and reality is one reason weight gain during pregnancy can easily overshoot recommendations.
What matters just as much as the calorie count is what those calories contain. Your protein needs during pregnancy are about 71 grams per day, and your iron needs jump to 27 milligrams per day. A few smart snack choices can cover both:
- Yogurt smoothies with greens, berries, or nut butter deliver protein and calcium in one glass.
- Hard-boiled eggs are easy to batch-cook and provide high-quality protein with minimal prep.
- Walnuts or mixed nuts pack healthy fats, protein, and calories into a small handful.
- Roasted chickpeas or fava beans offer iron and fiber. Pair them with something rich in vitamin C (bell pepper slices, strawberries, or an orange) to help your body absorb the iron.
- Hummus with raw vegetables like carrots and broccoli adds fiber and protein without relying on processed snack foods.
Weight Gain to Expect
The second trimester is when steady weight gain really begins. If you started pregnancy at a healthy weight, the target is about 1 pound per week through the second and third trimesters. If you started at a higher weight, the goal is closer to half a pound per week during that same period.
The total weight gain recommendation for your entire pregnancy depends on your pre-pregnancy BMI:
- Underweight (BMI under 18.5): 28 to 40 pounds total
- Normal weight (BMI 18.5 to 24.9): 25 to 35 pounds total
- Overweight (BMI 25 to 29.9): 15 to 25 pounds total
- Obese (BMI 30 or higher): 11 to 20 pounds total
These ranges exist because gaining too little or too much both carry risks. Insufficient gain is linked to lower birth weight, while excessive gain is associated with larger babies, more difficult deliveries, and greater postpartum weight retention. The second trimester is a good time to check whether your trajectory is on track, since the rate of gain during this period tends to predict the overall pattern.
Why You Don’t Need Extra Calories in the First Trimester
A common question that follows the second-trimester search is why the first trimester doesn’t come with its own calorie bump. The reason is simple: the embryo is tiny, and the metabolic demands of early pregnancy are small. Your body is doing important work in the first 13 weeks, but the energy cost is negligible compared to what comes later. Most of the calorie increase in pregnancy is driven by the baby’s growth, the expansion of the placenta, and the buildup of maternal fat stores, all of which accelerate in the second and third trimesters.
The progression from 0 extra calories in the first trimester to 340 in the second and 450 in the third mirrors the actual energy curve of pregnancy. It’s a gradual ramp, not a sudden leap. If you find yourself hungrier earlier, eating slightly more nutrient-dense food is fine, but there’s no physiological reason to deliberately increase your intake before the second trimester begins.