Liver damage can start even before a baby is born. A 2025 study published in Liver International found that babies exposed to an unhealthy diet during pregnancy already showed signs of liver injury — even before birth.1 This early damage is part of a growing liver condition now affecting up to 1 in 3 children in the U.S.
Simply put, it’s a buildup of fat inside the liver that leads to swelling, scarring and eventually serious damage if not reversed. The surprising part? These children didn’t look sick. They weren’t overweight and had no obvious signs of blood sugar or insulin problems. But their livers were already showing damage — all linked back to what their mothers ate during pregnancy.
How Mom’s Diet Shapes Baby’s Liver Before Birth
The study revealed that when pregnant mothers followed a Western-style diet, high in unhealthy fats and refined sugar, their babies developed liver scarring and bile acid problems before they were even born.2 Researchers used Japanese macaques to show that these changes mimicked a common liver disease in children, which involves fat buildup, inflammation and scarring in the liver.
• Even switching to a healthy diet later didn’t fully fix the problem — The animals who ate a healthier diet after birth still showed liver stress and bile duct overgrowth. Researchers found signs of scarring and activated liver cells trying to repair the damage. Once the process was set in motion during pregnancy, it didn’t stop just because the diet improved later.
• Specific types of scarring proteins were elevated — The researchers measured two proteins that form scar tissue and found significantly more in the livers of animals whose mothers ate a Western diet. One marker was 37% higher in those animals. The liver cells responsible for scar formation were also more active.
• The worst damage occurred in animals who stayed on the Western diet after birth — When the unhealthy diet continued after weaning, the scarring, oxidative stress and bile acid buildup were even worse. Their livers were flooded with bile acids and couldn’t properly clear them, which kept the damage going.
Why Bile Acids and Oxygen Matter for Liver Health
Bile acids are natural chemicals your liver makes to help break down fats. But when they build up too much, they become toxic. One of the liver’s jobs is to keep these acids in balance, clearing out what’s not needed.
In babies exposed to an unhealthy diet during pregnancy, this system broke down. Their livers kept making more bile acids but couldn’t remove them fast enough, which led to damage and scarring. In short, a baby’s liver relies on balance — and that balance gets disrupted by poor diet, even in the womb.
• The liver’s “off switch” stopped working — Normally, your liver has an internal system that acts like a thermostat, telling it when to stop making bile acids and when to clear them out. In these animals, that system wasn’t working right. Some of the genes that help remove bile acids were active, but the ones that signal the liver to stop making more weren’t doing their job. That caused toxic bile to get trapped in the liver, leading to inflammation and tissue damage.
• Low oxygen in the womb made things worse — Babies whose mothers ate an unhealthy diet during pregnancy also had lower oxygen levels in their blood. Low oxygen, even in small amounts, makes the liver more vulnerable to damage. In the study, babies with less oxygen had higher levels of toxic bile acids and more scarring in the liver. It created the perfect storm — low oxygen, toxic buildup and early liver stress.
• Babies’ livers started overgrowing in the wrong way — The liver has small tubes called bile ducts that help carry bile acids out of the liver. In healthy babies, these ducts grow in a controlled way. But in babies exposed to an unhealthy diet, the liver started growing too many of these ducts before birth — and they didn’t stop growing. This overgrowth is a sign the liver is under constant stress and trying to repair itself. Instead of healing, it created more problems.
• The damage started before birth and couldn’t be reversed later — The babies exposed to unhealthy diets already had the wrong types of bile acids building up in their livers before they were born. The enzymes that usually help control this were slowed down or blocked. All of this happened without any sign of infection or inflammation. It was just the result of what the mother ate — and once it started, eating healthy later wasn’t enough to undo the damage.
Supporting Cellular Energy Production Is Key to a Healthy Pregnancy
The Liver International study suggests that once the liver starts going down this unhealthy path, it’s hard to turn things around. That’s why pregnancy is the most important time to take action. The food you eat during those nine months builds the foundation for your child’s liver, metabolism and future health. It’s the blueprint — and you’re the architect.
If you’re pregnant or planning to become pregnant, the choices you make now affect your child for the rest of their life. This includes how well their liver functions and how resilient they are to chronic diseases.
Your developing baby is especially sensitive to linoleic acid (LA), a polyunsaturated fat found in nearly all vegetable oils and most ultraprocessed foods. LA disrupts your mitochondria — the parts of your cells that make energy — and that makes it harder for your baby to build healthy tissues, including in the liver. My advice is simple: protect your baby’s health by protecting your own cellular energy first. Here’s how you do it:
1. Eliminate vegetable oils from your diet — If you are pregnant or trying to conceive, this is the most important dietary change you can make. Vegetable oils like soybean, sunflower, safflower, corn and canola oil are everywhere — in processed foods, salad dressings, sauces, snacks and even “healthy” packaged meals.
Olive and avocado oils are often mixed with vegetable oils, making them unreliable. LA is a mitochondrial poison that damages both your health and your baby’s. Instead, use ghee, grass fed butter or beef tallow for cooking.
2. Keep your total LA intake below 5 grams a day — If you can get it below 2 grams, that’s even better. Track your intake for a few days using an online nutrition tracker to get a sense of where you are. If you’re eating out, you’re almost certainly going over. Even organic and gluten-free processed foods often contain vegetable oils. If it comes in a package, assume it has LA unless proven otherwise.
3. Avoid eating out during pregnancy — I know it’s inconvenient, but restaurant food — especially fast food and takeout — is loaded with vegetable oils. Even “clean” establishments almost always cook with LA-rich oils because they’re cheaper and shelf-stable.
You won’t see them on the menu, but they’re hiding in dressings, marinades, sautéed veggies and more. If you’re serious about protecting your baby’s future liver health, prepare your meals at home with healthy fats.
4. Switch to low-LA animal protein like bison, lamb or grass fed beef — If your go-to proteins are chicken and pork, it’s time to make a switch. This meat is typically extremely high in LA. Focus on incorporating bison, lamb and other ruminant meats as your primary protein sources instead.
5. Build your meals around energy — not restriction — Pregnancy is not the time to be low-carb, low-fat or low-calorie. Your baby needs fuel, and that means you do too. Prioritize meals that support mitochondrial function: carbohydrates from fruit, protein from collagen-rich sources and saturated fats from grass fed animal sources.
These steps don’t just lower your child’s risk for liver disease. They give you more energy, better digestion and a smoother pregnancy. You’re not just growing a baby — you’re building their entire metabolic blueprint.
FAQs About Maternal Diet During Pregnancy
Q: How does an unhealthy diet during pregnancy affect my baby’s liver?
A: A Western-style diet high in unhealthy fat and refined sugar, especially from vegetable oils, damages your baby’s liver starting in the womb. It disrupts bile acid regulation, triggers oxidative stress and causes fibrosis — scarring that persists for years, even if your child eats a healthy diet after birth.
Q: Are there visible signs of liver damage in babies?
A: Not necessarily. Babies might look healthy and not be overweight, but their livers could already show signs of stress and damage.
Q: Why is linoleic acid so harmful during pregnancy?
A: Linoleic acid, found in vegetable oils and processed foods, poisons your mitochondria and disrupts your bile acid signaling pathways. This leads to bile acid buildup and liver stress in both you and your baby. The result is long-term liver dysfunction and increased disease risk.
Q: Can switching to a healthy diet after birth reverse the damage?
A: Not completely. Research shows that liver damage caused by maternal diet continues in early childhood even if the child eats well after birth. That’s why it’s so important to reduce harmful fats like LA during pregnancy itself, before the damage begins.
Q: What steps can I take to protect my baby’s liver health during pregnancy?
A: Eliminate vegetable oils, keep linoleic acid under 5 grams daily, avoid dining out, focus on ruminant animal proteins like lamb and bison, and fuel your mitochondria with healthy carbs, collagen-rich protein and saturated fats. These steps help build a strong metabolic foundation for your baby.