Last week news of a study evaluating the timing of solid food introduction for infants emerged. It got a ton of press because the study evaluated the timing of solids on the likelihood of obesity at 3 years of age. Researchers divided babies into 2 groups, those that received partial or full breast milk until 4 months, and those that were weaned from breast milk and received formula exclusively before 4 months of age. Researchers then determined when babies were given solid food (rice cereal, biscuit, pureed “baby” food, etc) of any kind.
The results proved notable. Babies who received exclusive formula and solid foods before 4 months of age were 6 times more likely to be obese as a 3 year-old (defined as BMI over 95%, sum of triceps and subscapular skinfolds). This however, was not true for the babies that were receiving breast milk of any kind. So this study may not be applicable to many babies; in the US for example, 25% of infants are never breastfed and approximately half are breastfed for less than 4 months. Yet still, this sheds light on what we can do to help. Use this data when Grandma Trudy is urging you to feed your infant cereal at 3 months. Or why it’s best to wait until 4 months when you get excited about starting solids. Those of you who didn’t wait? Before you spin your wheels with worry about that bite of rice cereal you gave your baby at 3 1/2 months, read on. Because although, if it were my child, I wouldn’t give baby food before 4 months, there may be more to consider when it comes to timing.
Study Design and Results:
- 847 babies enrolled in the study and were divided into two groups: those with exclusive formula feeding (33%) or those with breast milk feeding or partial breast milk feeds (67%). There was no explanation if they asked moms about pumping milk or how they were giving breast milk. From my read of the study, if a baby had any breast milk at all until 4 months of age they were in the breast-feeding group. This is a unique take; most studies do the opposite. That is, they include babies in the breast milk group if exclusively breast feeding and put partial or mostly formula-fed babies in the formula group.
- The primary focus of the study was on the timing of introduction of solid foods categorized as <4 mo, 4 to 5 months and >6 months of age to the outcome of obesity at age 3.
- Researchers evaluated effect of maternal race, ethnicity, age, education and household income on choices to breast feed or formula feed. Mothers reported their prepregnancy weight and height. Researchers evaluated gestational age, birth weight, birth height, and controlled for change in weight between 0 and 4 months of age because of the suspicion that, “Mothers may perceive rapidly growing infants as requiring solid food supplementation in addition to breast milk or formula.”
The Study Results:
- Formula-fed babies that received food before 4 months of age were 6 times more likely to be obese as a 3-year old compared to those that didn’t get solid food (anything but formula) before 4 months.
- There was no effect on breast-fed babies in regards to early introduction of solids before 4 months and obesity risk.
- Interestingly, breastfeeding status was associated with timing of intro to solid foods. Only 8% of breast-fed babies, compared with 33% of formula-fed infants, started solids early, before 4 months.
- Like many studies before, breast-fed babies were less likely to be obese at age 3. A reminder that breast feeding may be a great, protective measure to avoid increased risk of overweight and obesity. For mom, too!
So okay, what to do with this? Know that there is little benefit to starting solids before 4 months of age. Previous studies have found that babies who were started on solids prior to 4 months of age were also worse sleepers. Read my blog post about rice cereal introduction and sleep.
Tips on Introduction of Solid Foods and Obesity Risk:
- Breastfeed a baby if possible. In addition to the immune protection, maternal effects, and economics, breastfeeding really may be protective against obesity. That’s a huge win! So why didn’t breast fed babies have the same risks when getting solids before 4 months of age? Researchers theorized that breast feeding may promote self-regulation of an infants’ energy intake, and that mothers may learn to recognize hunger cues differently in breast-fed babies. Because of this, they felt breast-fed babies didn’t have the same increased risk of obesity when started on solids early (<4 months of age) like the formula fed babies.
- Start solids after 4 months of age, particularly if your baby is formula fed. There is no great data to support early introduction of solids. Remember, rice cereal doesn’t help babies sleep through the night, despite the myth…
- I generally recommend starting solids at 6 months of age. However, new recommendations from the AAP Committee of Nutrition suggest that starting iron-fortified cereals at 4 months of age, particularly in breast fed infants, can protect against iron deficiency.
- If your baby is slow to take pureed foods, even at 6 months, don’t worry. In this study, there was no association with risk of obesity for babies that delayed introduction of solids even after 6 months.
- Remember that consensus is hard to find in most any medical decision. The AAP recommends delaying introduction of solids to at least 4 to 6 months of age while the World Health Organization recommends solid food introduction only at 6 months of age to promote exclusive breastfeeding. Talk with your baby’s pediatrician if you get confused by these recommendations…
We didn’t start solids until after six months. Elizabeth was in the 97% for weight and height and I didn’t think she needed anything else as she obviously wasn’t wasting away. She was exclusively breastfed, she refused even a bottle of pumped milk. And when she did start solids, she didn’t really eat anything for a whole month and then didn’t eat much until she was ten months old, which is when she really started using solids as a food group and not a pastime. And she’s showing absolutely no signs of obesity at age two, she’s actually pretty skinny now, not that age two is by any means conclusive.
It’s an interesting hypothesis about hunger cues for partially breastfed babies. I could definitely tell if my babies were hungry or just needed comfort. Did the study mention who fed the babies? My experience was that my exclusively-BF baby was generally overfed in daycare. She consumed the same volume of milk as the formula-fed babies. For a while I thought it was because my trusty Medela wasn’t getting as much of the rich hindmilk. Then I caught on that the daycare providers encouraged the babies to finish their bottles, especially if it was expressed breastmilk. It might be the sobs on anguish from moms when they read that any milk had gone to waste. 🙂
Wendy Sue Swanson, MD says
No, no mention of who fed the baby. No mention if mom’s who pumped milk into bottles, etc…I agree that the milk can feel precious and understand how others may feed our babies differently during our absence. Was a tricky balance for me…
I know you also recommended that we start solids with Emma at 4.5 months due to (possible?) reflux. Might be interesting to write a blog post about signs of actual reflux vs. “normal” spit up.
I was unable to BF my first son due to a breast reduction. My second son was BFd for about a month before he started to lose weight from my low supply. So they were essentially both exculsively formula fed.
They were also both very large and very long children, who remain above the 97th percentile for height (and at the 75th for weight). I did give them rice cereal at about 6 weeks. I know it sounds utterly crazy… but here’s why. Both of them (maybe because they were and are big?) would eat an enourmous amount in the evening. They would eat upwards of 12 oz of formula. It was absolutely crazy making. So after 8 oz of formula (which is a LOT for a 6 week old), I’d give them some “thickened” formula… week rice cereal.
I did NOT WANT to do this. But the 14+ oz binges just didn’t seem healthy, and the doctor’s office didn’t really have any answers, and in 2001, information on the internet was sketchy at best. So I played it by ear, and felt that my “after 8 oz” rule was… okay.
The good news is that they are still both slender. My now 5 year old has a little sixpack. “Real” solid foods were introduced after 6 months, and I gave them little rice, and mostly organic, “homemade” pureed foods.
I’m not sure why I’m posting this… maybe because I think it’s good to remind parents that there are guidelines with solid science behind them, but that sometimes there are good reasons to “stray” from the guidelines. Parenting is not a one-size-fits-all proposition (not that I think the author is suggesting that it is)… but I did want to offer (at the risk of being flamed) the perspective of why we can’t always beat ourselves up if we don’t make all decisions “by the book.”
Wendy Sue Swanson, MD says
Amy, I’m with you. I certainly don’t think these studies provide “maps” for all of us. I remember freaking out when my first son (who got formula after I was hospitalized for a week and no longer able to breast feed him directly) would suck down 8-9 oz of pumped milk or formula before bed. He was only 2-3 months old. I remember asking my husband what to do??? Was I to hold off, let him have it all, how much was “too” much? He asked me what I would have said in the office….
But you bring up a great point. This research is simply supposed to help us understand. Not jail us into going against instinct. There are very rigid lines in medicine and we all do the best we can with each individual child–to support them and help them thrive.
Great blog post, as usual. I’m wondering what your take is on the possible connection between later solid food introduction and allergy? I thought I had read (not in a scientific journal, in a New Yorker article by Jerome Groopman, link below) that some researchers are wondering if the AAP recommendations to wait until 4-6 months until introducing solid food is actually increasing the cases of serious food allergies in western countries. As the mom of a breastfed, no solid until 6 months and now severely peanut allergic 3 year old, I’m wondering if there was something we or other families could have done differently. I’d love to hear your opinion on this. Thanks for all the great posts and keeping us informed!
Wendy Sue Swanson, MD says
My response is a whole blog post. NEED to get on it! There was a huge Finish study that came out just over a year ago and new guidelines that were published about 6 weeks ago that discuss this. It’s complicated and lacks consensus…but yes, hard to know how and what to advise at this point when it comes to protecting against development of allergies. Will get to it soon!
Just something I was wondering. My daughter was unable to nurse so I pumped and fed the milk to her in a bottle for 6 months (that was not fun, but I felt she deserved the best nutrition I could give her). At the ped’s recommendation we started rice cereal mixed with breastmilk at 4 months and she started feeding herself small bits of other foods by 8 months. At 11 months she eats nearly everything especially vegetables and american cheese (blame her dad:). She is petite (5th percentile in weight, 20th percentile in height) but tracking on the growth chart normally.
The question is if it is the breastfeeding that makes the difference, or is it the breastmilk, or both?
Wendy Sue Swanson, MD says
I have no idea. From the explanations in the discussion, I think the researchers would lean on thinking it’s the breast feeding, not the breast milk. But this study simply didn’t evaluate your question. I too, gave one of my son’s pumped milk (but only lasted a bit over 4 months—you’re impressive!!) and look back and wonder how that may have changed things for him.
Like most moms, I did the best I could and yes, I worked hard for that breast milk. But the formula was great for him, too 🙂
I remember reading other summaries of this study back when it came out, and the question that comes to mind (unless I missed the mention of the answer somewhere) is whether or not it’s possible that the link is not necessarily the timing of the feeding but the food smarts or nutritional intelligence of the parents who felt babies need solid food before four months. What goes on in the children’s meals after they start solid foods up until they are three years old? I am a big fan of breastfeeding. I am a big fan of waiting on solid foods. However, I also like to understand the evidence a little more clearly. And why the partially formula fed children were put in the breast fed group. I suspect that advocates of breast feeding and advocates of waiting until after four months are fairly well informed nutritionally and that carries into the choices they make for their babies when they transition to solids. I remember seeing an obese three year old on some horrid daytime talk show and hearing the mother say he loved fried chicken since he was six months old so she fed him friend chicken. Yikes. I’d like to know more about what those children ate after the introduction of solids, before four months and after four months introduction.
Wendy Sue Swanson, MD says
Isabelle, I think you’re right to want to know more about what the babies-then-toddlers ate later. Unfortunately, their diet wasn’t investigated after looking at the timing/introduction of solids up until 6 months. Primarily because researchers were targeting the timing of solids on 3 year old weight status. But yes, those parents that introduced early versus those that didn’t may have had different views on foods, etc and toddler diet, activity level, etc wasn’t something that was controlled. …so could be a huge confound-er!
I read this study with interest when it was published, with a special eye toward the flurry of media attention paid to it, as I am both a new mother and a health care PR professional (at Penn! so I am thrilled to see an alum doing such great work with a blog!)/former newspaper health reporter. I was plagued by significant supply problems while nursing my daughter, to the extent that she still had not regained her birthweight (7 lbs 2 oz) by the time she was a month old, in spite of copious help from a lactation consultant, a breastfeeding support group and numerous nurse-pump-bottlefeed experiments suggested by the LC and pediatricians. What I learned from that rather traumatic period is that infant feeding is, despite the best intentions of many, not a science, but rather, a bit of a crapshoot. So, from six weeks on, she was exclusively formula-fed, and her weight perked up immediately — it was a profound relief to not eye the scale with dread each time she got weighed, but rather quickly, we were buffeted into the other camp of neurosis, worrying that she was OVERweight when she shot up into the 85th percentile in less than a month. We started her on solids — I slaved away to make homemade baby food — at just under 5 months, at which time she’d been gulping down 40 oz of formula a day for weeks. She did fine, eats with relish and now, at 9 months, it is a true joy for my husband and I to see her joyfully feed herself the various “big-people” foods that we make for her. To the previous commenters’ point about what children are eating during toddlerhood, I have cast my lot with making feeding her good food a key priority in parenting her for this point in her life, and although that’s a time-consuming endeavor, it feels like one of few things in the child-rearing realm that I can attempt to exact even a tiny bit of control over!
Wendy Sue Swanson, MD says
Holly, thanks. So great to see you here.
I’m going to film a quick video this afternoon with a similar take. I’m with you….often there is less science (and control) to these decisions than we’d like!!
maria cecilia tacchi says
the fact that they didn’t take into consideration diet after breastmilk/formula makes this study invalid. It is not only possible, but probable that those who didn’t introduce solids before 4 months had a very different take on diet, supporting this is the fact that introducing solids before 4months was more common in the formula-fed babies.
I’m sorry but I think you can’t draw any conclusion from this article. It is badly designed and it shoulnd’t have been published, the only thing it achives is inducing guilt in mothers who couldn’t breastfeed and had to introduce solids early for whatever reason.
I agree with the others that this could be due less to the timing of introducing solids as it is the associated lifestyle characteristics of the parents. Isn’t formula usage associated with a lower economic level? As well as introducing solids early? These could very well all be connected.
i gave my 15 year old solids at three months and she is not obese. she was also not breastfed as i had no milk come through. she is also a very good sleeper. i now have a five month old baby which is also bottle fed as no milk came through and i also had to start him on solids at three months because he wanted more. we also had an issue with gaining weight as he has my metabolism. since having him i have found that there are way too many experts and studies telling us how and when to feed our children. where were those experts a hundred years ago and as parents what were we doing with our babies? The same thing we do today, gut instinct, and your baby will always let you know what they want. there is no reason why a person needs to listen to an expert
makuku claudious says
i just want to ask,What are the sffects of introducing solid foods to a child less than 4 months
Wendy Sue Swanson, MD, MBE says
I wrote a post on this!
It’s called “If it were my child: no solid food before 4 months”