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  • Suzanne

Safety of 2021 Diet Trends During Pregnancy, Breastfeeding for Infants and for Children

Updated: Mar 4, 2021

This post will explain if the following trends are safe for pregnancy and breastfeeding women as well as infants and kids:

Scroll to the end for the summary infographic.


Keto Diet

The Keto Diet may not have been new in 2020 but it continued to rise in popularity this past year with some help from the viral bell pepper sandwich TikTok. Questions still remain; what is the keto diet? Is it the key to good health and is it safe?

Essentially the Keto Diet is a very low carb, high fat diet. This way of eating puts your body in a state of ketosis, transforming your body into a fat burning machine. Sounds great, but what does this really mean and how is it achieved?

Well, carbohydrates are the body's main source of energy, when consumed they are broken down into glucose units. When we restrict the amount of carbohydrates we consume, our body must switch from glucose to another source of energy, in the case of a high fat keto diet, the body will choose fat. The body converts fats into ketones which can be used for energy instead of glucose. This increase in ketones is what is known as ketosis.

Ketosis has been linked to weight loss, reduced appetite and improvements in cholesterol, blood pressure and blood sugar levels. However, it is still unclear whether the keto diet is effective in the long term and may be difficult for many to maintain as it is very restrictive. With any restrictive diet also comes risks.

Keto Diet in Pregnancy

  • Ketones occur naturally during pregnancy. Between morning sickness, food aversions and changes in metabolism, pregnant bodies often experience mild ketosis.

  • However, pregnancy is not the time to start a restrictive diet, which can increase the rate of ketosis.

  • The safety of the keto diet during pregnancy has not been widely studied.

  • If you have been following the keto diet pre pregnancy, it is important to speak to a doctor or registered dietitian about continuing or modifying your diet and monitoring nutrition status.

  • As with any eating pattern followed during pregnancy care must be taken to avoid weight loss, and ensure energy and nutrient needs of both mom and baby are met.

  • Following a keto diet may lead to low levels of certain vitamins causing deficiencies and can impact the growing baby. For example, Folate is a crucial vitamin when it comes to fetal nervous system development and cell growth and is often seen in low levels in keto and low carb diets.

  • Decreasing carbohydrates can also lead to a decrease in fibre intake This can exacerbate constipation commonly experienced during pregnancy.

  • Fruit and vegetable are loaded with vitamins and minerals but consumption of these foods tends to be lower on a keto diet since many contain some carbohydrate.

Keto Diet in Breastfeeding

  • We don’t not know the impact of ketones in breast milk.

  • High fat foods like meat and full fat dairy can be very filling which may lead mothers to consume less calories than needed for adequate milk production.

  • Ketosis can also lead to increased fluid loss. Since hydration is crucial while breastfeeding this could be cause for concern.

  • There have been a few cases of lactation ketoacidosis as a result of consumption of a low carb diet while breastfeeding.

    • Ketoacidosis occurs when a high level of ketones accumulates in the blood and begins to throw off its pH. This condition can be life threatening.

Infants and Children

Unless indicated by a healthcare practitioner for medical reasons, the keto diet is not recommended for infants and children. Children are more susceptible to the side effects of a keto diet and for some children these side effects may be severe or life threatening. They include:

  • Dehydration

  • GI disturbances such as nausea and vomiting, diarrhea and constipation

  • Electrolyte imbalance

  • Low blood sugar

  • Growth impairment

  • Vitamin and mineral deficiencies


Intermittent Fasting

Intermittent fasting, like Keto has been around for a while but was still a popular nutrition buzz word in 2020. Intermittent fasting involves designating a window of time for fasting and a window of time for eating.

Technically, we all do this to a certain extent as the window in which we are sleeping is also a window of fasting which we break in the morning! Intermittent fasting however takes this further with some people not breaking their fast until noon while others only consuming one large meal a day in the evening before fasting all over again. For some people this doesn’t take much discipline, depending on your preferences and daily schedule this way of eating may work for you (although for a die hard breakfast fan like me this would be downright impossible.) Intermittent fasting has been shown to promote weight loss, lower blood pressure and may be beneficial for the prevention of diabetes and cardiovascular disease.

There are many different ways to carry out an intermittent fast. The latest of 2020 is a thing called Circadian Rhythm Fasting.

  • This is a way of eating lines up with your internal clock by establishing a ~12 hour eating window during daylight hours and fasting for the remainder of the day.

  • This sounds alot like the old rule of not eating 2-3 hours before bedtime, right? Same trend new packaging!

  • This diet can be an issue for people with an irregular sleep schedule.

Note: Those with a history of disordered eating or people on diabetes medications should not attempt to fast without consulting a doctor first.

Intermittent Fasting in Pregnancy

  • Intermittent fasting is generally not recommended during pregnancy because it can lead to weight loss.

  • Weight loss should not be attempted during pregnancy where there is an increased need for calories and nutrients.

  • In general, when eating is restricted, there is a risk of malnutrition and this is amplified in pregnancy.

Intermittent Fasting in Breastfeeding

  • Like with pregnancy, breastfeeding moms simply need more calories to carry out milk production.

  • If calorie needs aren’t met this can have a significant impact on energy levels.

  • While your body will likely still be able to produce enough milk, fasting may alter the nutrient profile of breastmilk.

Intermittent Fasting in Infants and Children

  • Intermittent fasting is not recommended for infants and children as they are in a stage of rapid growth and development and need, you guessed it, energy and nutrients.

  • However, being too full before going to bed can have an impact on a child’s sleep so it may be beneficial to set dinner at a time that allows them time to digest before bed.


Counting Macros

What are macros and why are people counting them? The term “macros” refers to macronutrients, also known as, carbohydrate, fats and proteins. These nutrients are unique as they are the body's sources of energy or calories. There is a set of guidelines known as the Acceptable Macronutrient Distribution Range or AMDRs that provide recommendations on how much of each macro typically makes up a healthy diet that provides all the nutrients we need and contributes to the prevention of chronic disease. The AMDRs provide a range of percentages of total calorie intake.

The guidelines for adults are as follows:

When someone is counting macros they may use these ranges or may set specific values based on their unique goals; weight loss or muscle building etc. Their diet is then tracked to ensure that these targets are met and food choices are based on what macronutrients are required.

Counting Macros in Pregnancy and Breastfeeding

  • The AMDRs for pregnancy and breastfeeding women are the same as the guidelines for adults listed above.

  • Some people may find it useful to count macros to plan or track their intake and ensure they fall within these ranges. However counting macros for the purpose of weight loss is not recommended during pregnancy.

Counting Macros in Children

  • Children ages 4-18 have the same AMDRs as adults.

  • Children ages 1-3 AMDRs are a slightly different

Carbohydrates: 45-65%

Proteins: 5-20%

Fat: 30-40%

  • Counting macros for children and infants is unnecessary and are likely being met when provided a balanced diet. It is important to recognize the significant difference in fat AMDRs in children compared to adults to ensure kids are enough fat as fat is a crucial component of the diet of 1-3 year olds


Plant Based/Vegan Diet

Increasing concerns about climate change and sustainability, ethical concerns as well as personal health goals have led to an increase in the popularity of plant based or vegan diets in 2020. Canadians are opting for plant based milks more and more and chains like KFC and A & W have no included plant based meat options along with their regular offerings.

While I can’t speak to the healthfulness of these specific products, incorporating plant based protein in the form of soy, beans and legumes, nuts and seeds can contribute to overall health. Canada’s Food Guide now puts greater emphasis on plant-based proteins and makes recommendations on how to incorporate more plant based protein in your diet. Whole grains and fruits and vegetables are also key components of a plant-based or vegan diet, and something we could all get more of.

Plant Based/Vegan Diet in Pregnancy

  • A well-planned vegan diet is considered safe during pregnancy as long as calorie and nutrient needs are being met. Iron requirements are just one of the nutrients that pregnant women need a whole lot of and this can be difficult but not impossible to obtain while following a vegan diet. For tips on getting the most iron out of your plant based proteins read this this blog post on iron needs in pregnancy.

  • Other nutrients of concern include protein, vitamin D, calcium, DHA, vitamin B 12 and zinc-- fortified foods and supplements will likely be required to meet intake requirements.

  • It may be a good idea to speak to your doctor or registered dietitian to assess your current nutrition status and diet quality to ensure nutrition needs are being met.

  • While pregnancy may not be a great time to start a completely vegan diet you can certainly begin to add more plant based proteins to your current diet.

Plant Based/Vegan Diet in Breastfeeding

  • Like during pregnancy, breastfeeding increases the nutrient needs of mom and nutrient stores must be maintained in order to ensure nutritional adequacy of breast milk.

  • If you follow a vegan diet and are exclusively breastfeeding it is extremely important to ensure you're getting adequate amounts of nutrients to support you and your baby’s nutritional needs.

  • Regardless of diet type, breastfed babies should always be given a vitamin D supplement.

Plant Based/Vegan Diet in Infants and Children

Here is a summary of studies found on the Canadian Pediatric Society website regarding vegan diets in infancy and childhood:

  • Many long-term studies on populations of lacto-ovo-vegetarian children have documented appropriate growth and development from infancy through adult life.There are however insufficient studies on energy intake and long-term growth of strict vegans to permit conclusions.

  • Restrictive vegan diets, may cause energy deficits because of low energy density and excessive bulk, presenting challenges in feeding smaller children.

  • Data on strictly vegan children have demonstrated intakes of calcium below recommendations.

  • Vegan diets are relatively deficient in the long-chain omega-3 fatty acids docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA), which are found largely in fish, seafood and eggs.

While a balanced vegan diet is possible, it should be carried out in consultation with a dietitian or a doctor and growth, calorie and nutrient intake are monitored as there are many nutrients of concern (iron, zinc, calcium, fatty acids, B12 and vitamin D). Supplementation may be needed.



safety of keto diet, intermittent fasting and counting macros in pregnancy and breastfeeding
Safety of 2021 diet in pregnancy, during breastfeeding & in infancy

We just do not have enough research to know whether keto and Intermittent fasting is safe in pregnancy and breastfeeding.

Counting macros and plant-based vegan diets can be safe during pregnancy and breastfeeding if mom is aware and able to ensure her diet meets the specific nutrient needs that are increased during this life stage.

None of these diets are safe in infants however, a vegan diet may be complete and adequate with the help of a registered dietitian.

As a mom, dietitian and former yoyo dieter, I often tell parents that we often start to deal with our own relationship with food when we become parents. We start to think about whether we are emotional eaters and if we actually recognize our own hunger and fullness cues. We start to question if we can role model healthy eating patterns to our kids because we might need to work on this ourselves.

Turning our focus into creating a healthy relationship rather than focusing on following strict diet regimes might be beneficial to you, your kids and even your grandkids.

Good places to start exploring mindful eating are two blog articles written by two of my dietitian colleagues:

Click HERE for a mindful eating activity you can do with your kids.


Disclaimer: All the advice shared here is general information. Consult your doctor for personalized health information. Compiled September, 2020

Sabrina Mastrangelo

Special thanks to Sabrina Mastrangelo, 4th year nutrition student at Ryerson University who did the research for this post.


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