Weaning 3 day rule

Should you follow the three-day rule when weaning your baby?

If you follow any weaning forum or advice page, you may still encounter advice that you should introduce your baby to one new food every three days during weaning. But is this the right way to do things?  Should this three-day rule apply to all foods or just some?  In this blog, we’ll pull apart the three-day weaning rule and help you understand when it might apply, but more importantly, when it doesn’t!


This blog will cover

  •  What is the three-day rule during weaning?
  •  Why the three-day rule shouldn’t apply to all foods and the importance of variety during weaning
  •  How to approach food allergen introduction

What is the three-day rule when weaning?

The origins of this piece of weaning advice take a lot of work to pinpoint. Still, the three-day weaning rule continually does the rounds across forums and social media.  It suggests that you should offer your baby one new food every three days to allow enough time to see if your baby can tolerate this food and that it isn’t associated with any adverse reactions.   Some of this advice is likely rooted in advice that surrounds the introduction of common allergens to your baby’s diet, where a systematic approach is needed to ensure there is no confusion about any possible allergic reactions.  But does this rule need to apply to all foods?  My advice is certainly not, and here’s why…


Debunking the three-day weaning rule – why it shouldn’t apply to all foods


The biggest worry about applying the three-day rule to all foods offered during weaning is that it immediately restricts the variety of foods your baby is exposed to. Think about it this way: if you introduce just one new food every three days, the maximum number of foods you can introduce to your baby across one month is 10!  The reason this matters is that offering as much variety as possible is essential during weaning for a variety of reasons, including;


  • Support of texture progression – babies have a crucial window of opportunity to support acceptance of a wide variety of textures, usually between 6-10 months.  Restricting foods offered means limiting the variety of textures your baby is exposed to across various food groups.
  • Sensory and motor development: During weaning, babies rely on a variety of foods to support their sensory and motor development.  Dietary diversity supports skill development, e.g., biting, chewing, self-feeding, and sensory exploration.
  • Gut microbiome developmentAs you’ll know from our other blogs, weaning is a crucial milestone in your baby’s gut microbiome development.  Dietary variety during weaning directly influences the growth and diversity of your baby’s gut garden.  This can then have a knock-on impact on many other areas of their health, e.g. immune development.
  • Diverse palate – dietary variety also means babies are exposed to a wide range of different tastes and flavours.  Like texture, babies tend to have a critical window where they are very accepting of different tastes, and this can support the foundations children need to go on to accept a balanced and varied diet.
  • Nutritional needs – While milk remains a crucial source of nutrition for babies during weaning, it’s important not to overlook the nutritional contributions food will start to make to your baby’s diet.  Key nutrients such as iron and zinc are essential to provide during weaning, and over time, your baby will rely more on food than milk as their primary source of nutrients.  With this in mind, restricting the exposure and variety of foods your baby has via the three-day rule means the approach could also impact their nutritional intake over time.

What about introducing allergens?  Does the three-day rule apply here?


A more systematic approach can be helpful when introducing common food allergens during weaning, such as cow’s milk, egg, peanut, soya, wheat, tree nuts, sesame, fish and shellfish. In practice, we recommend that these foods are offered one at a time to ensure there is no risk of confusion if your baby does react to them during weaning. Usually, it is suggested that you start with small amounts of the allergen, e.g. ¼ teaspoon of peanut butter and increase gradually.  For food allergens such as milk, egg, soy and wheat, which can be commonly associated with delayed-type (NonIgE mediated) reactions, allowing 2-3 days after exposure may be beneficial before progressing onto other allergenic foods as delayed reactions can present from 2-72 hours after exposure.  So, in the case of these foods, yes, the ‘three-day’ rule can apply!


Interestingly, research into food allergy prevention has also highlighted the importance of ‘dietary diversity’ during weaning to support allergy prevention.’   One research paper found that the more dietary diveristy (variety) a child had in the first year of life, the lower the odds of food allergy over their first ten years.  It showed that introducing each additional food at six months of age reduced by 10.8% the odds of developing food allergy over the first ten years of life1.


So, the key takeaway here is that unless a medical professional advises you to approach all foods during weaning with the three-day rule, it should not be necessary or a requirement for most babies. Reducing exposure to foods and variety during weaning has the potential to impact everything from your baby’s gut microbiome to taste and texture acceptance.



  1. D’Auria E, Peroni DG, Sartorio MUA, Verduci E, Zuccotti GV and Venter C (2020) The Role of Diet Diversity and Diet Indices on Allergy Outcomes. Front. Pediatr. 8:545. doi: 10.3389/fped.2020.00545
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