Twin pregnancy diet and weight gain

Eating For Two: Gestational Weight Gain

Let’s talk about your twin pregnancy diet and weight gain, two important topics.

During pregnancy, weight gain is inevitable. After all, you are growing a human!

When you are eating for two, you might be wondering about gestational weight gain.

There are a variety of feelings and misconceptions when it comes to weight gain during pregnancy–some women try their best not to gain any, while others use the 9 months as a total free for all.

That brings to light the question–how much weight should women actually be gaining when pregnant? Today, we will take a look into various studies to determine what the right answer is for you. 

This blog is for educational purposes only and is not a substitute for professional medical guidance. 

Twin pregnancy diet and weight gain

Weight gain during pregnancy is not a new topic for researchers in the reproductive world.

It has been studied for years and continuing research comes out somewhat frequently. If you remember in our preconception blog, (which you can read here) we talk about maintaining a healthy BMI for optimal fertility and keeping up with exercise and a healthy diet and not focusing on pounds per week.

Those facts still ring true, even into pregnancy and women carrying twins or triplets.

According to a peer reviewed journal article published in early 2019, “From 1990 IOM developed some recommendations for weight gain during pregnancy in order to optimize fetal growth and postpartum outcome (Table 1).”

 BMIRecommended total gestational weight gain
Underweight<18,5 kg/m212,5-18 kg
Normal18,5-24,5 kg/m211,5 -18 kg
Overweight25-29,9 kg/m27 -11,5 kg
Obesity≥30 kg/m25-9 kg

  (Nartea et. al, 2019)

This table shows that the more you weigh above your recommended weight prior to pregnancy, the less weight you should gain during pregnancy.
So, this is based on your pre-pregnancy body mass index (BMI). 

Research has shown there is an increased risk of cesarean section, abnormal fetal growth, gestational diabetes and other medical ailments that are aligned with excessive weight gain in pregnancy (Sahin & Madendag, 2019).

It is stated, however, that professionals are unsure whether it is the pre-pregnancy weight or gestational weight gain when you are “eating for two” that is to blame for the additional risk, which brings us full circle to maintaining a weight that is healthy for you

You can focus on eating a well-balanced diet and small meals eaten more frequently can help with digestion and weight gain. Although not intended to be a substitute, a prenatal vitamin will also provide benefits to mom and baby.

Although used as a measurement tool in research, BMI is not the end-all-be-all, and there are many other measurements to access overall health status pregnant or not.

However, BMI does give us a consistent reference point when it comes to the range of healthy gestational weight gain, so that is what I will be referencing throughout this blog.  

A study posted on September 1st, 2019, titled The relationship between body mass index before pregnancy and the amount of weight that should be gained during pregnancy: A cross-sectional study, states “30-70% of women gain excessive weight during pregnancy and after each pregnancy they gain an average of 2 kg to 5 kg of extra weight” (Ozdilek, et al 2019).

So, what gives? 

What is it that is causing the additional gestational weight gain?

According to Dr. Patricia Lo, M.D.,  your baby is only utilizing 26% of the weight gain for energy and growth.

So, what about the rest of the weight? It’s being used for you.

You are growing a little life! You are creating new tissues and increasing your blood and fluid volume to ensure your sweet baby can thrive in his or her new environment for the next nine months. She states,

You might feel as though you’re packing on pure fat, but most of the new weight can be attributed to fluids and expanding body tissue. With a full-term pregnancy weight gain of about 30 pounds, you get 4 pounds of increased fluid, 4 pounds of added blood volume, 2 pounds of breast tissue, 2 pounds of uterus tissue, 1.5 pounds of placenta (an organ that didn’t exist before!), 2 pounds of amniotic fluid, 7 pounds of fat, protein, and other nutrient stores, and 7.5 pounds of joy (that’s your baby!)” (Daly and Reece, 2019). 

Pretty amazing, huh? 

It goes without saying that women who don’t gain enough weight during pregnancy also run severe risks–many experience premature births or babies born with low birth weights. This could be caused from nausea and vomiting due to morning sickness in the early stages of pregnancy. If these symptoms continue throughout pregnancy, seek professional medical advice. In a medical review journal, Kathleen Rasmussen, Sc.D., R.D. states, “Babies who are small for their gestational age — meaning they’re full-term but low-weight — can have all sorts of problems at birth and later in life, including respiratory, cardiovascular, and digestive issues” (Daly and Reece, 2019). 

So, here’s your reminder–these months are not about how much or how little weight you gain.

Of course, there are extremes to everything, and the goal is to keep you and baby as healthy as possible regardless of how much you weigh. But, the weight gain is normal and necessary during a multiple pregnancy.

Continue to eat whole, well-balanced meals and stay as active as you can (doctor permitting, of course), and enjoy the beauty of what your body can do when pregnant with twins. 

Want to ensure you are meeting your needs and gaining the right amount of weight for you?


Written by: Kaleigh Eastep, Dietetic Intern

Reviewed/edited by: Ryann Kipping, MPH, RDN


Daly, K., & Reece, T. (n.d.). Pregnancy Weight Gain: What to Expect and Why It’s Not As Bad As You Think. Retrieved from

Eraslan Sahin, M., & Col Madendag, I. (2019). Effect of Gestational Weight Gain on Perinatal Outcomes in Low Risk Pregnancies with Normal Prepregnancy Body Mass Index. BioMed Research International, 1–4.

Nartea, R., Mitoiu, B. I., & Nica, A. S. (2019). Correlation between Pregnancy Related Weight Gain, Postpartum Weight loss and Obesity: a Prospective Study. Journal of Medicine & Life, 12(2), 178–183.

Ozdilek, R., Aba, Y. A., Aksoy, S. D., Sik, B. A., & Akpak, Y. K. (2019). The relationship between body mass index before pregnancy and the amount of weight that should be gained during pregnancy: A cross-sectional study. Pakistan Journal of Medical Sciences, 35(5), 1204–1209.