“You are what you eat” is one thing, but as an expectant mom, it’s sobering to realize that your baby “is what you eat” as well. That means it’s important to know which foods will give your little one the best chance as he or she develops in your womb.

For insight, we turned to Nicole Avena, Ph.D., a neuroscientist who focuses on appetite and nutrition, and author of What to Eat When You’re Pregnant (Ten Speed, 2015). “We know from research studies that what you eat when you’re pregnant directly affects your baby,” Avena says. “It’s important to make sure that baby is getting all of the right nutrients and vitamins.”These highlights from Avena’s research will help you give your little one the healthiest start possible.

First Trimester

What’s going on with baby: This is the time when baby starts to develop every part of its body. By week eight, every major body system is formed.

What’s going on with you: Nausea is most common in these first few months.

Nutrients you need: Folate—or its synthetic form, folic acid— is vital for proper development of the neurological system. This takes place in the first four weeks—sometimes before you even know you’re pregnant, which means all women of childbearing age should consume at least 400—600 mcg daily. Folate is also needed for cell division and making DNA. You’ll also need to get plenty of protein, iron and healthy fats—all of which are necessary for you and baby, but often get neglected if you’re nauseous.

Key foods: Lentils, spinach, beets, eggs, wild-caught salmon

Tip: If the smell of eggs makes you queasy, Avena suggests hard-boiling them and eating them cold, which minimizes the odor.

 Second Trimester

What’s going on with baby: Baby’s bones, teeth and muscle tissues are developing, as are its necessary fat stores. Skin forms, and sight and hearing develop enough for baby to react to the outside world, including light and voices.

What’s going on with you: You likely feel better than you did in the first trimester, but leg cramps are common.

Nutrients you need: Calcium is essential for baby’s strong bones and teeth (and yours!). Healthy fats help with brain formation and fat stores, and potassium can minimize your leg cramps.

Key foods: Cheese, yogurt, lean pork, broccoli, avocado

Third Trimester

What’s going on with baby: Most of baby’s weight and brain mass accumulate during this period. In week 29, baby begins to store nutrients such as calcium, iron and phosphorus that will carry it through its first six months of life before you introduce solid foods.

What’s going on with you: As your insides get squished, constipation is frequently a problem.

Nutrients you need: Baby needs plenty of healthy fats to feed its growing brain and to make fat stores that will keep it warm outside of your womb. Protein, iron, and the broad spectrum of vitamins and minerals continue to be important. High-fiber foods are good for baby and can ease your constipation.

Key foods: Coho salmon, walnuts, acorn squash, brown or wild rice, kale

Kellee Katagi is one of those strange souls who actually enjoys working out for the sake of working out. She’s spent most of her 20-plus-year writing and editing career covering fitness, nutrition and travel, as well as outdoor sports ranging from skiing to spelunking to street luge (yes, that’s a thing).