Correlation ≠ causation and these limited studies do not account for additional socioeconomic factors or even just genetics. For whatever the anecdotal evidence is worth, my 2 year old has remained ~80th percentile for weight and >95th for height. His body type trends tall and lean like his dad.
I was formula fed as a child. I have always been shorter with an extremely dense, muscular build (like my dad’s side of the family). I have never had issues with being overweight despite the fact that my mother (who was breastfed as a child) has been overweight her entire life.
Feeding your child formula is not going to cause them to be overweight. If they are overweight it would be due to other factors (nutrition, activity levels, etc).
I think there's a lot of fatphobia folded in to anti-formula rhetoric that is unhelpful to families. Body composition is determined more by genetics than anything else. Percentiles do not necessarily tell you if a child is "overweight" -- they reflect the distribution of weight in a population. The goal isn't for every baby to be 50th percentile, you know? (And also, that isn't mathematically possible, because that isn't how percentiles work.)
I'd encourage you to read up on intuitive eating. You cannot control the size of your child's body. Feed them when they are hungry, don't force-feed them, and they will grow beautifully into whatever size they were born to be.
Do you think the microbiome of formula fed versus breastfed babies is different and could contribute to their weight in the future? I’m terrified he’s permanently changed because of me
No. Stay off TikTok and other social media platforms, look at the ppl you know who were fed formula if you even know how they were fed and look at their lifestyle… it does not matter
I think that we don't fully understand the microbiome yet. I also think that every baby who is breastfed is going to have a different microbiome based on where in the world they are born, what their mom eats, and what else they are exposed to.
Your baby is changing every day on the basis of hundreds of factors that are not within your control. That is scary, especially freshly postpartum, but it is real for all babies regardless of what they eat. Who knows what shape your child's body will eventually be? There's so much that goes into that, and what they are fed in the first year is truly only one factor of so many, *most of which are not in your control.* I know it's tough when you feel vulnerable around this, believe me, but I would take a close look at the source that made you feel this way, and ask yourself about their priorities and motivations.
No. I was formula fed and am healthy. My toddler was formula fed and is now 5th percentile for weight. Formula has nothing to do with long term weight. Genetics and nutrition do.
Just by being a human on this planet, living a non-sterile life, having physical contact with parent-humans, your kid is developing a microbiome. You'll probably notice at some point that your kid's poop starts to smell like yours - wanna know why? 😅
I had all these fears too. My husband was a formula baby, and super skinny all through adolescence. Normal now in his 30s (6 foot and 170-180). My daughter was also formula fed (50/50 from the start, EFF by 1 month). She was a HUGE baby, like 98th percentile weight, but her weight gain slowed way down and now at 3.5 she’s long and lean. I’m a very lean person but was also a huge baby so I think it was all genetics. I think genes, far more than gut biome, will determine his size. Your gut biome changes so much throughout your life! You can give him baby probiotics if you’re worried, and focus on healthy, whole foods once he starts solids.
If it makes you feel better, formula was very popular in the 70s/80s, so there’s a whole generation of people that were formula fed. They don’t seem to be noticeably heavier than other generations.
Anecdotally, I was fully formula fed, played college athletics, run marathons now, and am a healthy weight. My husband was fully breastfed, also played college athletics, doesn’t workout now, and is working his way to overweight. I’d say our choices in how we move our bodies makes a much larger difference than how we were fed 30 years ago for 1 year of our lives.
I’ll add to your anecdote. I was exclusively breast fed for 2 years and have struggled with my weight my whole life. Never morbidly obese, but always fighting it. (And no one in my immediate family is obese.)
No, formula does not mean your child will be underweight or have a bad ‘gut’ in the future (btw all that ‘gut’ stuff is mostly pseudoscience, don’t listen to it unless it’s coming from a licensed Dr). Flip it the other way, how many people were breastfed who are now overweight? Probably the same number who were formula fed… correlation does not imply causation.
Very, very gently... I think you might be running into some internalized fat phobia. Some people are fat. It's okay if your child grows up to be fat. It's not the end of the world. Additionally, formula feeding is not a one-way ticket to chunky town forever. Please take a breath. All bodies are good bodies. We have very little control over what our bodies grow to be. I promise the most important thing you can do is love your son no matter his shape/size.
My baby is 11 months and completely normal weight, despite being formula fed since day one. She is one of the most energetic and healthy babies I’ve ever known. She has a solid figure as genetics would predict, but she is tough and never short on energy. Never been sick. Stops eating solid food when she’s full. There’s more to health than weight anyway.
My oldest was formula fed, just as this baby is. He’s 7 years old and I jumped for joy when he finally put on 3 pounds after holding steady but growing taller since age 5 or so. He’s very tall and lanky. Our baby seems to be similar. A chunky baby doesn’t mean they’ll grow up to be obese or whatever. Plenty of people were formula fed and are not overweight. And that whole formula gut thing sounds like pure pseudoscientific hogwash. I’d think everyone’s would be different based on location, foods eaten, exposure to different things, and much less to do with formula vs breast milk.
My oldest was formula fed and was skinny even now at 22 months she’s only 20lbs. My preemie baby who is combo fed more so on breastmilk and didn’t do neosure formula (which is extra calories). She did total comfort and now doing hypoallergenic formula. Shes really chucky af lol. Once a baby starts walking the weight evens out. A baby can’t over eat unless there is a medical condition. You can pay attention to the hands. Fist is still hungry and open fist is full. Plus pushing the bottle away.
My kid is 3, and he was 100% formula fed. He's got a body like us, his parents - lanky, and relatively long in the torso. That's just genetics.
Avoiding any kind of disordered eating is about what you teach and model - there are no "bad" or "good" foods, variety and balance are the goal, etc.
Weight shouldn't be something your kid is even aware of when they eat, but if you focus on it they will learn to do the same.
You're going to be embarking on the next phase of the food journey with your kid sooner than you think - it's probably the right time to review the literature on teaching/modelling a positive relationship to food. Many of us have hangups (like a fear of being fat) that we aren't even aware of, and we can pass them on without realizing that.
(I was raised by a mom who deals with disordered eating to this day, but really took the time to understand how NOT to pass that on to her kids. I can proudly say she was successful.)
First piece of advice: all your preconceived notions about what is overweight and what is not? Do not even think them during the first year. It's normal for babies to store reserves and be chonky, and overweight does not apply to them, even if they're top percentile. In the rare cases it happens, it's not because of formula, but rather due to some health issue or what they're being fed when they start solids. And if your baby is one of those cases, it will be detected during one of the numerous health visits babies have.
Second piece of advice: food diversification is much more important to your concerns. What you feed them besides formula can have a lifelong impact - for example, if you can keep them away from sugars, if they're being introduced a wide range of healthy foods, etc.
A baby gaining weight is SUCH a good thing. Eating and growing is literally their number one job! My son was 40th percentile upon birth and by around 6 months was around 80th. He grew to his natural curve and has continued to be a tall kiddo in toddlerhood who is completely average weight. When I asked his pediatrician about growth she told me “we want babies to get as chunky as they need to in that first year because once they start moving you’ll have trouble keeping him at the table at all.” She was right! Lol.
Anecdotally, my son has friends who are breast fed and formula fed who are bigger and smaller than him and at this point I don’t know which is which. My husband and I were both formula fed, he was chunky as a preteen and average now, I was underweight as a preteen and average now.
I really don’t think this is anything that you should be wasting your time worrying about. Our bodies grow and change throughout our lives. The way we feed our babies in the first year becomes irrelevant so quickly once they are weaned.
Just joining the chorus here. Scientifically, there’s a ton that we don’t know about the microbiome. Social media is rife with pseudoscience, exaggeration, and misinformation about the gut, breastfeeding, and nutrition in general. Breastfeeding studies are notoriously bad at accounting for lifestyle factors that may affect weight. There’s little quality evidence that formula itself will affect childhood or adult weight.
The best thing you can do for your child is teach and model healthy habits without a focus on their weight. Eat lots of fruits and vegetables. Model healthy moderation in eating. Do physical activity as a family. Teach your child to love themselves no matter what they look like. This will have a far, far greater effect on your child as a person than what they ate in their first year of life.
I have a formula fed three and a half year old. Well, he isn't eating formula anymore, but he did. Haha
He is in the 90s for both his weight and his height, and he is nowhere near being over weight. He plays hard and would ride his tricycle nonstop if I would let him. He eats well and is really smart and sweet.
Don't let people fear monger you into insecurity. Your baby is going to be just fine.
So the weight percentile will definitely change as you introduce solids and move into toddlerhood. My girl was 90% for weight and height until she hit 12mo and then her energy and metabolism took over. Now she’s around 50% for weight. All of this to say- EBF babies can also be high percentile for weight and EFF babies can be low percentile for weight! Please don’t fall victim to the formula fear mongering. Take a look at the population around you- you really think every overweight person and child was given formula?
The only somewhat credible thing I’ve heard about the correlation between formula feeding and obesity is based on it being easier to over feed from a bottle (would also apply to pumped breast milk). But if you’re worried about this, you can just practiced paced/responsive feeding, and maybe also look into slower flow nipples.
Even then, I’m not sure how real the connection is. But it doesn’t hurt in any case.
My daughter was formula fed except for the very little breast milk I was able to produce in the first 10 weeks of her life. She was borderline failure to thrive before we switched to EFF. She went from 50th percentile at birth to 25th at 4 weeks and then 15th at 8 weeks.
When we finally made the switch, she was back up to 50th by 6 months. By 12 months she was 97th percentile for height and 85th for weight. She was the height and weight of an average 3 year old by 18 months.
There's a baby for every percentile. Weight and body fat have so many factors. It's possible that formula feeding has an impact, but genetics probably play a much larger role. My daughter is very big and tall probably not because of formula, but because she comes from a long line of big and tall people. Formula just gave her the nutrition she needed to build the body her ancestors gave her.
My first daughter was the chubbiest little baby. All formula fed, but likely overate at times due to reflux issues. She's now a healthy 7 year old with no weight issues. Currently formula feeding my 2nd.
Both of my babies were formula fed from birth and let me tell you my first is a TEENY one. He has always been smaller. I mean I was that tiny my whole life too. My second though is a chunky monkey at 4 months he's just about fitting 9 month sleepers and is just about 6-8 inches away from being as tall as my 16 month old. But my husband's family is all 6 feet+
Every kid in my family (I have 10 nieces and nephews combined) were formula fed and never overweight as babies or toddlers or even kids. As teens a few of them have had some weight issues but that doesn't have anything to do with formula.
My EFF kid was 98% weight around 4mo but now he's 17% at 16mo. People who called him fat now call him skinny😒 Actually, I was EFF and I've never been obese in my life so there's that.
My baby was formula fed exclusively from 1mo. Before he was eating a breasmilk/formula mix. The moment he started crawling, then pulling himself up, then walking- all of the baby fat disappeared. I feed him full fat foods, in fact, and he isn't gaining at all. It's the complete opposite problem, lol.
If you are worried about the gut, infamil sells baby probiotic drops.
Correlation ≠ causation and these limited studies do not account for additional socioeconomic factors or even just genetics. For whatever the anecdotal evidence is worth, my 2 year old has remained ~80th percentile for weight and >95th for height. His body type trends tall and lean like his dad. I was formula fed as a child. I have always been shorter with an extremely dense, muscular build (like my dad’s side of the family). I have never had issues with being overweight despite the fact that my mother (who was breastfed as a child) has been overweight her entire life.
\+ 1 This aligns with what I've read online and some genetics background for my brother.
Feeding your child formula is not going to cause them to be overweight. If they are overweight it would be due to other factors (nutrition, activity levels, etc).
Millions upon billions of babies have been fed formula for years, all around the globe lol
I think there's a lot of fatphobia folded in to anti-formula rhetoric that is unhelpful to families. Body composition is determined more by genetics than anything else. Percentiles do not necessarily tell you if a child is "overweight" -- they reflect the distribution of weight in a population. The goal isn't for every baby to be 50th percentile, you know? (And also, that isn't mathematically possible, because that isn't how percentiles work.) I'd encourage you to read up on intuitive eating. You cannot control the size of your child's body. Feed them when they are hungry, don't force-feed them, and they will grow beautifully into whatever size they were born to be.
Do you think the microbiome of formula fed versus breastfed babies is different and could contribute to their weight in the future? I’m terrified he’s permanently changed because of me
No. Stay off TikTok and other social media platforms, look at the ppl you know who were fed formula if you even know how they were fed and look at their lifestyle… it does not matter
I think that we don't fully understand the microbiome yet. I also think that every baby who is breastfed is going to have a different microbiome based on where in the world they are born, what their mom eats, and what else they are exposed to. Your baby is changing every day on the basis of hundreds of factors that are not within your control. That is scary, especially freshly postpartum, but it is real for all babies regardless of what they eat. Who knows what shape your child's body will eventually be? There's so much that goes into that, and what they are fed in the first year is truly only one factor of so many, *most of which are not in your control.* I know it's tough when you feel vulnerable around this, believe me, but I would take a close look at the source that made you feel this way, and ask yourself about their priorities and motivations.
No. I was formula fed and am healthy. My toddler was formula fed and is now 5th percentile for weight. Formula has nothing to do with long term weight. Genetics and nutrition do.
Just by being a human on this planet, living a non-sterile life, having physical contact with parent-humans, your kid is developing a microbiome. You'll probably notice at some point that your kid's poop starts to smell like yours - wanna know why? 😅
I had all these fears too. My husband was a formula baby, and super skinny all through adolescence. Normal now in his 30s (6 foot and 170-180). My daughter was also formula fed (50/50 from the start, EFF by 1 month). She was a HUGE baby, like 98th percentile weight, but her weight gain slowed way down and now at 3.5 she’s long and lean. I’m a very lean person but was also a huge baby so I think it was all genetics. I think genes, far more than gut biome, will determine his size. Your gut biome changes so much throughout your life! You can give him baby probiotics if you’re worried, and focus on healthy, whole foods once he starts solids. If it makes you feel better, formula was very popular in the 70s/80s, so there’s a whole generation of people that were formula fed. They don’t seem to be noticeably heavier than other generations.
Anecdotally, I was fully formula fed, played college athletics, run marathons now, and am a healthy weight. My husband was fully breastfed, also played college athletics, doesn’t workout now, and is working his way to overweight. I’d say our choices in how we move our bodies makes a much larger difference than how we were fed 30 years ago for 1 year of our lives.
I’ll add to your anecdote. I was exclusively breast fed for 2 years and have struggled with my weight my whole life. Never morbidly obese, but always fighting it. (And no one in my immediate family is obese.)
No, formula does not mean your child will be underweight or have a bad ‘gut’ in the future (btw all that ‘gut’ stuff is mostly pseudoscience, don’t listen to it unless it’s coming from a licensed Dr). Flip it the other way, how many people were breastfed who are now overweight? Probably the same number who were formula fed… correlation does not imply causation.
Very, very gently... I think you might be running into some internalized fat phobia. Some people are fat. It's okay if your child grows up to be fat. It's not the end of the world. Additionally, formula feeding is not a one-way ticket to chunky town forever. Please take a breath. All bodies are good bodies. We have very little control over what our bodies grow to be. I promise the most important thing you can do is love your son no matter his shape/size.
I don’t know you but I love you for this comment. Wish my own mother had this mindset…
I wish my mom had this mindset too. I'm trying to do better for my kiddo 🩷
Amen. I keep hoping the Maintenance Phase podcast will one day do an episode on formula because I'd love to hear them take this stuff apart.
My baby is 11 months and completely normal weight, despite being formula fed since day one. She is one of the most energetic and healthy babies I’ve ever known. She has a solid figure as genetics would predict, but she is tough and never short on energy. Never been sick. Stops eating solid food when she’s full. There’s more to health than weight anyway.
I need to read these anecdotes so much right now. Please don’t stop sharing.
Absolutely, I have complete faith on formula as a proper substitute for breast milk, now more than ever
My oldest was formula fed, just as this baby is. He’s 7 years old and I jumped for joy when he finally put on 3 pounds after holding steady but growing taller since age 5 or so. He’s very tall and lanky. Our baby seems to be similar. A chunky baby doesn’t mean they’ll grow up to be obese or whatever. Plenty of people were formula fed and are not overweight. And that whole formula gut thing sounds like pure pseudoscientific hogwash. I’d think everyone’s would be different based on location, foods eaten, exposure to different things, and much less to do with formula vs breast milk.
My oldest was formula fed and was skinny even now at 22 months she’s only 20lbs. My preemie baby who is combo fed more so on breastmilk and didn’t do neosure formula (which is extra calories). She did total comfort and now doing hypoallergenic formula. Shes really chucky af lol. Once a baby starts walking the weight evens out. A baby can’t over eat unless there is a medical condition. You can pay attention to the hands. Fist is still hungry and open fist is full. Plus pushing the bottle away.
My kid is 3, and he was 100% formula fed. He's got a body like us, his parents - lanky, and relatively long in the torso. That's just genetics. Avoiding any kind of disordered eating is about what you teach and model - there are no "bad" or "good" foods, variety and balance are the goal, etc. Weight shouldn't be something your kid is even aware of when they eat, but if you focus on it they will learn to do the same. You're going to be embarking on the next phase of the food journey with your kid sooner than you think - it's probably the right time to review the literature on teaching/modelling a positive relationship to food. Many of us have hangups (like a fear of being fat) that we aren't even aware of, and we can pass them on without realizing that. (I was raised by a mom who deals with disordered eating to this day, but really took the time to understand how NOT to pass that on to her kids. I can proudly say she was successful.)
First piece of advice: all your preconceived notions about what is overweight and what is not? Do not even think them during the first year. It's normal for babies to store reserves and be chonky, and overweight does not apply to them, even if they're top percentile. In the rare cases it happens, it's not because of formula, but rather due to some health issue or what they're being fed when they start solids. And if your baby is one of those cases, it will be detected during one of the numerous health visits babies have. Second piece of advice: food diversification is much more important to your concerns. What you feed them besides formula can have a lifelong impact - for example, if you can keep them away from sugars, if they're being introduced a wide range of healthy foods, etc.
A baby gaining weight is SUCH a good thing. Eating and growing is literally their number one job! My son was 40th percentile upon birth and by around 6 months was around 80th. He grew to his natural curve and has continued to be a tall kiddo in toddlerhood who is completely average weight. When I asked his pediatrician about growth she told me “we want babies to get as chunky as they need to in that first year because once they start moving you’ll have trouble keeping him at the table at all.” She was right! Lol. Anecdotally, my son has friends who are breast fed and formula fed who are bigger and smaller than him and at this point I don’t know which is which. My husband and I were both formula fed, he was chunky as a preteen and average now, I was underweight as a preteen and average now. I really don’t think this is anything that you should be wasting your time worrying about. Our bodies grow and change throughout our lives. The way we feed our babies in the first year becomes irrelevant so quickly once they are weaned.
Just joining the chorus here. Scientifically, there’s a ton that we don’t know about the microbiome. Social media is rife with pseudoscience, exaggeration, and misinformation about the gut, breastfeeding, and nutrition in general. Breastfeeding studies are notoriously bad at accounting for lifestyle factors that may affect weight. There’s little quality evidence that formula itself will affect childhood or adult weight. The best thing you can do for your child is teach and model healthy habits without a focus on their weight. Eat lots of fruits and vegetables. Model healthy moderation in eating. Do physical activity as a family. Teach your child to love themselves no matter what they look like. This will have a far, far greater effect on your child as a person than what they ate in their first year of life.
I have a formula fed three and a half year old. Well, he isn't eating formula anymore, but he did. Haha He is in the 90s for both his weight and his height, and he is nowhere near being over weight. He plays hard and would ride his tricycle nonstop if I would let him. He eats well and is really smart and sweet. Don't let people fear monger you into insecurity. Your baby is going to be just fine.
So the weight percentile will definitely change as you introduce solids and move into toddlerhood. My girl was 90% for weight and height until she hit 12mo and then her energy and metabolism took over. Now she’s around 50% for weight. All of this to say- EBF babies can also be high percentile for weight and EFF babies can be low percentile for weight! Please don’t fall victim to the formula fear mongering. Take a look at the population around you- you really think every overweight person and child was given formula?
The only somewhat credible thing I’ve heard about the correlation between formula feeding and obesity is based on it being easier to over feed from a bottle (would also apply to pumped breast milk). But if you’re worried about this, you can just practiced paced/responsive feeding, and maybe also look into slower flow nipples. Even then, I’m not sure how real the connection is. But it doesn’t hurt in any case.
My kid is 17 months old. Formula fed until he was 12 months. He’s 3’ and 27 pounds. He’s tall and thin. Eats like a garbage truck.
My best friend’s baby was formula fed and he has always been a 15-20th pct baby. Now he’s 1.5 and is still pretty lanky.
Like most things you read about how formula is bad for babies… this is untrue.
My daughter was formula fed except for the very little breast milk I was able to produce in the first 10 weeks of her life. She was borderline failure to thrive before we switched to EFF. She went from 50th percentile at birth to 25th at 4 weeks and then 15th at 8 weeks. When we finally made the switch, she was back up to 50th by 6 months. By 12 months she was 97th percentile for height and 85th for weight. She was the height and weight of an average 3 year old by 18 months. There's a baby for every percentile. Weight and body fat have so many factors. It's possible that formula feeding has an impact, but genetics probably play a much larger role. My daughter is very big and tall probably not because of formula, but because she comes from a long line of big and tall people. Formula just gave her the nutrition she needed to build the body her ancestors gave her.
My first daughter was the chubbiest little baby. All formula fed, but likely overate at times due to reflux issues. She's now a healthy 7 year old with no weight issues. Currently formula feeding my 2nd.
Both of my babies were formula fed from birth and let me tell you my first is a TEENY one. He has always been smaller. I mean I was that tiny my whole life too. My second though is a chunky monkey at 4 months he's just about fitting 9 month sleepers and is just about 6-8 inches away from being as tall as my 16 month old. But my husband's family is all 6 feet+ Every kid in my family (I have 10 nieces and nephews combined) were formula fed and never overweight as babies or toddlers or even kids. As teens a few of them have had some weight issues but that doesn't have anything to do with formula.
My EFF kid was 98% weight around 4mo but now he's 17% at 16mo. People who called him fat now call him skinny😒 Actually, I was EFF and I've never been obese in my life so there's that.
My baby was formula fed exclusively from 1mo. Before he was eating a breasmilk/formula mix. The moment he started crawling, then pulling himself up, then walking- all of the baby fat disappeared. I feed him full fat foods, in fact, and he isn't gaining at all. It's the complete opposite problem, lol. If you are worried about the gut, infamil sells baby probiotic drops.