NutritionDietIntermittent Fasting While Pregnant - Is Weight Loss During Pregnancy Safe?

Intermittent Fasting While Pregnant – Is Weight Loss During Pregnancy Safe?

If you’re planning to expand your family or expecting a baby it’s natural to be concerned about the health and nutrition of your child. During pregnancy your eating habits play a role in meeting your babys nutritional needs. Considering this you might be contemplating some adjustments.

Intermittent fasting (IF) has gained popularity in diet trends. However when it comes to meeting the needs of pregnancy is fasting safe? In short no; the potential risks outweigh the supposed benefits of IF during pregnancy. This article takes a look, at the claimed advantages of intermittent fasting and how they relate to being pregnant.

What Is Intermittent Fasting?

Intermittent fasting involves cycles of eating and fasting. It's not usually recommended during pregnancy because the mother needs a steady diet to support the development of the baby. Fasting can lead to nutrient deficiencies and is not considered safe for the baby.

Can Intermittent Fasting Affect A Mother’s Mental Health?

Intermittent fasting can have impacts, on a mothers mental well being. On one hand it can enhance mood and cognitive abilities by promoting brain health. However it is crucial to note that it may also induce stress or anxiety particularly if it disturbs eating routines or fails to meet nutritional requirements. Therefore it is advisable to approach fasting with care and seek guidance from a healthcare expert.

Is It Advisable To Do Intermittent Fasting During Pregnancy?

Pregnancy triggers many changes in the body that require various lifestyle adjustments. For example, your pre-pregnancy diet may not be sufficient to meet your baby’s nutritional needs during the nine months of meticulous development inside your body.

There is little research on the effects of intermittent fasting, during pregnancy. Unlike diets that focus on reducing calories, intermittent fasting (IF) involves eating all your calories within a specific time frame. For instance with 16/8 fasting you can eat during an eight hour window. Should avoid consuming anything for the remaining 16 hours of the day.

Intermittent fasting for religious purposes is an integral part of many faiths. However, some faiths make exceptions for pregnant women to minimise potential nutritional deficiencies during pregnancy. One notable study found that women who fasted during Ramadan in their second trimester were 35% more likely to give birth prematurely.

Many individuals engage in fasting for reasons, including religious beliefs or to achieve weight loss. However it is important to note that losing weight during pregnancy is not recommended. In fact the recommended healthy range for weight gain, during pregnancy varies between 11 and 40 pounds depending on your BMI before getting pregnant.

It’s important to realise that weight gain plays an important role in several aspects of a healthy pregnancy. Your baby may only account for seven or eight pounds of this, with the rest coming from increased blood and fluid volume, an enlarged uterus, and the mass of the placenta and amniotic fluid. These elements are essential for maintaining the mother’s wellbeing and the baby’s development in the womb.

To ensure nutrition for both you and your baby it is important to maintain a balanced diet during pregnancy. On average pregnant women require a 300 calories, per day to support their pregnancy while this requirement doubles for those expecting twins. Fasting during pregnancy can make it more challenging to fulfill these increased needs.

Is Intermittent Fasting Advisable During Pregnancy?

Is Intermittent Fasting Advisable During Pregnancy

To date, limited research suggests that intermittent fasting may help with weight management, stabilise blood sugar levels, reduce inflammation and lower the risk of cardiovascular disease in most people. However, there’s a big gap in the research on the effects of intermittent fasting on women’s health, particularly during pregnancy.

Intermittent fasting or IF doesn’t impose restrictions on the type or quantity of food you consume. Instead focuses on when you eat. Based on what we know about the nutritional needs during pregnancy this dietary approach is generally not recommended for expectant mothers. Even without limiting calories having a shorter window for eating naturally leads to consuming fewer calories. The duration of fasting can vary in different IF diets but considering the changing requirements, during pregnancy it’s not advisable to follow any enforced eating schedule.

Every pregnancy is different and each woman’s experience will be very different. Morning sickness can cause unintentional fasting episodes that aren’t usually a major problem. However, prolonged fasting, especially on an IF diet, can lead to nutrient deficiencies and dehydration.

Intermittent fasting (IF) can also pose a risk of hypoglycemia for women. It is crucial for the well being of both the mother and her baby to maintain proper blood glucose levels during pregnancy. Developing diabetes carries potential risks such as high blood pressure, premature birth and an increased likelihood of future type 2 diabetes. On the hand consistently low blood sugar levels can lead to symptoms like dizziness or reduced fetal movement. One common consequence of fasting is experiencing hypoglycemia due, to the inability to eat while fasting even if your energy stores are depleted.

How Should A Pregnant Woman Approach Breaking A Fast?

When breaking a fast, a pregnant woman should approach it carefully to ensure that both her and her baby’s health is protected. It’s a good idea to start with small amounts of easily digested foods such as fruit, vegetables or smoothies. Hydration is important, so drinking plenty of water is essential. Gradually introduce more substantial foods such as whole grains, lean proteins and healthy fats.

Make sure to pay attention to your body and not overeat. It’s an idea to seek guidance, from a healthcare expert who can provide personalized advice especially when it comes to addressing specific dietary requirements or concerns during pregnancy.

Downsides Of Periodic Fasting During Pregnancy

Periodic fasting is frequently promoted as a method for weight reduction in contemporary diet culture. Although it can aid in weight loss, regulate blood sugar levels, and may assist in managing some chronic conditions, it’s challenging to sustain over time and could adversely affect different aspects of life. In pregnancy, periodic fasting might harm the expecting mother’s mental and physical wellbeing.

Pregnancy brings about adjustments to your lifestyle that can make you feel somewhat disconnected from your usual routines. You might find yourself lacking the energy for those hikes with friends or unable to indulge in your favorite sushi spot. It’s possible that even feeling comfortable in your bed becomes a challenge.. When you add periodic fasting into the mix it further intensifies this sense of disconnection from your pre pregnancy life by restricting both your food intake and social activities. So if you happen to have plans for a dinner party, with friends it’s advisable to ensure it doesn’t coincide with a fasting period.

Periodic fasting can also diminish your breast milk production. Often called the “fourth trimester,” the period right after childbirth demands optimal nutrition to recuperate and foster breast milk generation if you opt to breastfeed. Nonetheless, without sufficient calories, protein, and fats, lactating mothers will experience a decline in milk supply.

Furthermore it is worth noting that intermittent fasting has the potential to impact fertility. If individuals are already underweight prior, to pregnancy engaging in fasting could result in further weight loss or hinder the necessary weight gain. It is important to consider that those who are underweight often experience decreased estrogen production, which can lead to menstrual cycles and potentially affect their ability to conceive.

What Are The Signs That Intermittent Fasting May Not Be Suitable During Pregnancy?

Intermittent fasting may not be appropriate during pregnancy if you experience signs of nutritional deficiency, such as persistent fatigue, dizziness or extreme hunger. Significant weight loss or inability to gain appropriate pregnancy weight is a concern. Frequent headaches, mood swings and a decrease in fetal activity may also indicate that intermittent fasting is affecting both maternal and fetal health. Always consult a healthcare professional before starting or continuing intermittent fasting during pregnancy.

Pregnancy Safe Options

It’s always an idea to consult with your healthcare professional or dietitian regarding your dietary needs during pregnancy. However starting off with a rounded diet that includes whole grains, fruits, vegetables and lean meats can be beneficial. Ensuring that your body receives the nutrients during this remarkable phase of growth and change is crucial and its important to advocate for yourself.

Rather than restricting your diet to a narrow time frame, it’s important to listen to your body’s signals and eat whenever possible. Hunger cues reflect your body’s needs, and meeting those needs is important not only for you, but also for your baby.

Alongside maintaining a rounded diet engaging in physical activity can also contribute to a healthy pregnancy. It’s important to consult with your doctor but try not to decrease your calorie intake and aim for approximately 30 minutes of moderate exercise every day. Exercise has been recognized for its ability to regulate blood sugar levels and facilitate an healthy weight gain during pregnancy.

What Alternative Might Be Recommended For Pregnant Women?

If pregnant women are seeking alternatives to fasting they can opt for a well balanced diet that includes plenty of fruits, vegetables, whole grains, lean proteins and dairy products. Eating meals at regular intervals can help maintain stable blood sugar levels. It’s important to stay hydrated by drinking an amount of water. Prioritizing dense foods, particularly those that are high, in folic acid, iron, calcium and omega 3 fatty acids is highly recommended.

It is advisable to limit processed foods in favour of whole, natural options. It is also a good idea to consult a dietician for personalised dietary advice.

Frequently Asked Questions

Are there any benefits to intermittent fasting for pregnant women?

While intermittent fasting may have benefits for non-pregnant individuals, such as weight management and improved metabolism, these benefits are not applicable during pregnancy. The focus during pregnancy should be on a balanced diet, not on weight management or metabolic changes.

What are the risks of intermittent fasting for pregnant women and their babies?

Risks include potential nutrient deficiencies, reduced foetal growth and hypoglycaemia (low blood sugar) in the mother. These risks can have significant implications for both maternal and fetal health, including potential effects on fetal brain development.

Can intermittent fasting affect the outcome of pregnancy?

Yes, intermittent fasting can affect pregnancy outcomes. Possible problems include low birth weight, premature birth and developmental delays. It’s important for pregnant women to get regular nutrition to avoid these risks.

What should pregnant women focus on instead of intermittent fasting?

Pregnant women should focus on eating a balanced diet rich in vitamins, minerals and essential nutrients. Frequent, small, nutritious meals are recommended. Consultation with a healthcare professional or dietician is essential for personalised dietary advice.

Is there a scenario in which intermittent fasting is recommended during pregnancy?

In general, intermittent fasting is not recommended during pregnancy. However, in some very specific medical scenarios, a healthcare provider may recommend modified eating patterns. These cases are rare and should always be supervised by a healthcare professional.


Initial research indicates that intermittent fasting might have effects on metabolism and blood sugar regulation potentially leading to a reduction, in blood pressure and a lower risk of heart disease. Nevertheless adopting eating patterns that restrict calorie intake and increase the chances of deficiencies goes against the principles of maintaining a healthy pregnancy.

The majority of expectant mothers can rely on their natural judgement to eat a nutritious diet. Your body is deliberately putting on weight to support your pregnancy, so losing weight is not advisable. Pregnant women should consume an extra 300 calories a day over and above their normal food intake to meet their body’s increased energy needs.

In general, dietary considerations during pregnancy are very personal, so it is important to consult your doctor or dietician before making any changes to your lifestyle.


  1. Gordon, B. (2019). “What is intermittent fasting?” Academy of Nutrition and Dietetics. Read Article.
  2. Tith, R.M., Bilodeau-Bertrand, M., Lee, G.E., Healy-Profitós, J., & Auger, N. (2019). “Fasting during Ramadan Increases Risk of Very Preterm Birth among Arabic-Speaking Women.” The Journal of Nutrition, 149(10), 1826–1832. Read Article.
  3. Anon. (2022). “Weight Gain During Pregnancy.” Centers for Disease Control and Prevention. Read Article.
  4. Longo, Valter D. & Mattson, Mark P. (2014). “Fasting: Molecular Mechanisms and Clinical Applications.” Cell Metabolism, 19(2), 181–192. Read Article.
Master of Science and Registered Dietitian Nutritionist at University of California

Paul Piepenbrok is a Registered Dietitian Nutritionist with over 12 years of experience. He specializes in the health sciences and writes extensively about nutrition and chronic disease. He holds a Master of Science degree in Human Nutrition and has completed post-graduate work in the Nutrition Sciences. The author has experience working in various healthcare settings, including hospitals, nursing homes, and public health departments. They have worked as a Health Facility Surveyor and a WIC Program Manager in Plano, Texas. Before becoming a full-time freelance writer, they successfully operated a telehealth wellness clinic, assisting clients in achieving their health goals, including weight loss, blood sugar control, liver function improvement, and overall health enhancement.

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