Does Breastfeeding Help You Lose Weight?
You may have heard that breastfeeding helps women lose the baby weight faster after giving birth. Maybe you’ve read it somewhere, maybe it was your friend or sister’s experience, or maybe you’ve seen it all over social media- moms “bouncing back” (insert eye roll) fast and crediting all the calories they’re burning from breastfeeding.
So, is this true?
The short answer: No.
It’s not completely impossible. But for most women, the act of breastfeeding does not directly help with weight loss. Overall, this notion that breastfeeding = weight loss is just another misguided and even harmful myth about postpartum bodies.
When it comes down to it, breastfeeding is amazing for a million reasons, but it’s not a weight loss tool. In fact, it can actually stall weight loss or contribute to weight gain.
Before you throw your hands up in the air, it’s important to learn exactly what’s going on in your body when you breastfeed- besides the stuff we’re commonly told like “you’ll burn 500 extra calories a day,” and “you’ll lose your belly quicker.”
Whether you’re currently pregnant and planning to breastfeed and wondering how your body will respond, or you are breastfeeding your baby and are finding that weight loss seems impossible, I want you to fully understand what’s actually going on.
Let’s break down the top factors involved with breastfeeding and your weight.
1) Breastfeeding can help your belly flatten faster, but not because it’s making you lose actual belly fat.
The hormone oxytocin is released when you breastfeed. It’s the same hormone that causes uterine contractions during labor and birth, and even postpartum. It’s why breastfeeding uterine cramps happen. It helps your uterus contract- to help you birth a baby, but then to return your uterus back to its original, non-pregnant size.
This means yes, your belly (which after you give birth can still look like you’re pregnant)- which houses your uterus- can decrease in size a bit faster if you breastfeed. It doesn’t mean you’ll have six-pack abs or even a belly that resembles your pre-pregnancy one, but breastfeeding can mean slightly quicker changes due to uterine contractions.
2) Breastfeeding uses an average of 670 calories a day. It doesn’t “burn” them, it requires them.
Let’s get something out of the way- calories aren’t bad. Diet culture has us so obsessed with how many calories we eat and “burn,”, especially in efforts to lose or even just maintain weight. We think that the more we can shift this equation- burn more than we consume- the better. It’s not true.
Our bodies require calories for fuel to help our bodies run. And breastfeeding places an additional demand for fuel on our bodies- around 670 calories on average, but more accurately, about 20 calories per ounce of milk. (So if you’re making 50 ounces of milk a day as some women do, that’s 1,000 calories)!
These calories (and with that, nutrients) are being used by the body to produce milk. So they need to be replaced through food. And if not, your body will do whatever is necessary to get them (producing milk is the priority)- meaning tapping into your own nutrient stores and breaking down your own bodily tissues.
Many women will see a drop in milk supply if they don’t eat enough. Others may not. But beyond milk, we need to ensure an intake of adequate nutrients to thrive- it’s not just important for providing nourishment to baby, but nourishing mom, too.
The recommendation to consume an additional 500 calories a day while exclusively breastfeeding- assumes that the remainder can come from mom’s fat stores, therefore supporting gradual weight loss. But actually, this isn’t as efficient of a process for many moms.
3) Prolactin- the hormone that promotes milk supply- makes you hungrier and can impact how you mobilize stored fat.
Prolactin is a breastfeeding hormone but it actually has numerous metabolic effects. For one, it actually increases your appetite. (If you’ve experienced ravenous, almost unbelievable hunger, especially in those early weeks, maybe you’re having an “aha” moment right now).
And you know what prolactin also does? it slows the breakdown of body fat. Yes, prolactin suppresses a hormone called adiponectin, which is secreted by our fat tissues and regulates the metabolism of fat and glucose. It also increases the activity of insulin and therefore, lowered levels lead to decreased insulin sensitivity and increased energy storage.
So while we tend to think of prolactin as only encouraging milk production, it also increases our appetites and impacts how our bodies store and break down fat. It’s pretty safe to assume that these are protective mechanisms by the body to ensure we have the fuel we need to make milk for our babies. Maybe our bodies actually don’t want to lose weight while lactating in order to assure we can nourish our babies while also not totally depleting our own bodies.
It’s common for women to store a little additional body fat as a “cushion” for milk production- especially women who struggle with milk production. In case of starvation, the body will have backup.
4) It’s common for breastfeeding moms to under-eat, which slows the metabolism.
Because of the additional caloric demands of lactation, but also just because of the nature of life with a new baby, it can be really difficult for a new mom to eat enough food.
And because new moms have all of this pressure to lose the baby weight and “bounce back” fast, they often feel pressured to diet- cut calories and restrict food- in an effort to reach these goals.
Just another misguided message from diet culture.
If we live on a calorie (and therefore, nutrient)-restricted diet, especially when the body has special priorities for those calories (lactation), our bodies will naturally “save” energy (i.e. store fat) by turning down energy usage and production- which is also a major reason new mamas are often exhausted!
Your metabolism- which is the sum of all chemical reactions in the body involved in keeping you alive and functioning- needs energy. And we get energy from food. If our bodies realize we’re not getting what we need, they’ll only prioritize what’s essential for survival (including the survival of our babies, i.e. making milk), and move other things down the list- digestion, brain function, hormone balance, and more.
Basically, in the case of under-eating (whether it’s intentional or not), the body wants to hold onto body fat as a survival mechanism and puts our metabolisms on power saver mode.
5) Sleep deprivation and stress both stall weight loss.
What else commonly happens alongside breastfeeding? Broken sleep- especially when babies cluster feed or even just nurse 1-2 times a night, which may cease over time but may continue until weaning. Lack of sleep- especially broken sleep- disrupts hormones, which has a direct impact on our weight.
The hormones influenced by sleep loss include insulin (the hormone that is released in response to blood sugar) as well as leptin and ghrelin (the hormones that dictate hunger and fullness respectively).
Insulin is a storage hormone- it shuttles glucose from our blood into our cells to be used for energy or stored for later use- in the liver, muscles, and fat cells. This is a natural and helpful system, but with sleep loss, our resistance to the cues of insulin increases, meaning the body produces more and more insulin to do the work it needs to do. This can mean increased glucose storage and over time, even increased blood sugar.
Lack of sleep has also been found to trigger decreased levels of leptin and increased ghrelin— leading to increased appetite.
Essentially, lack of sleep can make our bodies less responsive to insulin and can make us feel hungrier!
And of course, especially in the early months- breastfeeding or not- stress levels are usually high, which has similar impacts on the body. Cortisol (our main stress hormone) increases, impacting blood sugar (and insulin) and how the body stores fat. When cortisol is high, it mobilizes and stores glucose, therefore increasing blood sugar. This prompts the body to release insulin, which shuttles glucose into our cells for energy (or storage for later use). See where this is going again?
Moral of the story:
Your body is pretty amazing. It’s smart and will do what’s needed to prioritize your survival + nourish your baby.
Some moms do lose weight while breastfeeding, but there’s no proof it’s the breastfeeding that caused that to happen. It’s likely just a correlation. Nutrient status, sleep, and stress also plays big roles.
Many moms don’t lose weight while breastfeeding, only fully losing the weight they gained during pregnancy until after they wean. It doesn’t mean they’re flawed.
Weight loss- especially postpartum- depends on a lot- hormones and metabolic health, digestion and detox, genetics, stress, nutrient sufficiency, hydration, and activity. Weight loss is never a simple calories in vs. calories out equation.
But then what do you do? Just give up? Stop breastfeeding?
Heck no! Especially if you’re like so many new mamas and have struggled at all with breastfeeding, please do not give up on all that hard work.
Breastfeeding has so many amazing benefits- both for the baby, and for the mother- and even though it may not impact postpartum weight loss as you wish or even had planned, it’s still so important.
Plus, there’s a lot you can do to counteract some of the impacts and support your body in releasing stored body fat when it’s ready- and healthy.
Focus on nutrient-density and variety of your food intake to nourish your body more deeply instead of dieting, cutting calories, or restricting food.
Balance your meals with protein, fat, and carbs, and eat regularly to ensure you’re supporting healthy blood sugar balance.
Reduce unnecessary stress (tough, of course, but as a new mom, it’s so important to learn what you can let go of and what you can delegate). Find ways to manage the stress out of your control- meditate, spend time alone, get outside, or whatever helps you relax!
Prioritize sleep as much as possible. Of course, with a baby that wakes often or doesn’t like to sleep at all, this can be so hard. But there’s also some shifts you can make, too- like resisting the urge to stay up late, allowing others to help so you can grab a nap, and practicing better sleep hygiene. Check this post for some ways to get better sleep.
Enlist help. Whether it’s working with a IBCLC to troubleshoot breastfeeding struggles or seeing a therapist or counselor to work through postpartum challenges- including body image issues- or a functional nutritionist to help you best nourish and replenish your body, fuel breastfeeding, and strengthen the foundations of health that when weakened, can stall weight loss.
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