Gaining Weight While Breastfeeding? A Dietitian Explains What’s Normal, What’s Not, and How to Reset

Many moms hear that breastfeeding is a “calorie burner” and expect the pounds to melt away. But for plenty of women, the opposite happens - they hold onto weight, or even gain weight while breastfeeding.

With so much conflicting advice online, it’s hard to know what’s normal, when to be concerned, and how to get back on track. As a Registered Dietitian and Certified Lactation Counselor, I want to give you the evidence-based truth: what’s normal, what’s not, and how to reset in a way that supports both you and your milk supply.

What’s Normal

After working with many postpartum moms to resolve their postpartum weight loss struggles, looking at the research and going through my own postpartum weight loss challenges, I can tell you that the following is perfectly normal while trying to lose weight while breastfeeding:

1. Leaving the hospital and still looking pregnant

   It is absolutely normal to still have a 'pregnancy belly' for several weeks after giving birth. That is because the uterus takes about 6 weeks to shrink back down, fluid shifts take time, and abdominal muscles and skin don't bounce back right away. This is a normal part of recovery and not something that can be rushed.

   
   

2. Losing weight at a slow pace

   Once supply is established, a gradual weight loss of about 0.5 to 1 pound per week is considered normal and safe. Consider that one pound of body fat is roughly 3,500 calories, that means creating a daily deficit of 300 to 500 calories through a mix of balanced eating and gentle activity should result in a weight loss of about 0.5 to 1 pound per week (500 x 7 = 3,500). Any weight loss faster than that is either the result of losing water (not fat), or will eventually result in a dip in milk supply or a slow down of your metabolism. Slow and steady wins the race!

   
   

3. Increased appetite and snacking

   You WILL need more food while breastfeeding! Prolactin (the milk-making hormone) boosts hunger, and your nutrient and calorie needs are higher now than ever before! Don't feel guilty for 'being hungry all the time' - this is normal, and the body's way of making sure it gets all the nutrients it needs. (We will talk about strategies to make sure these cravings don't lead to weight gain below.)

   
   

4. Holding on to 5 to 10 pounds until weaning

   Research shows that many women retain a small amount of weight (often 1 to 7 pounds) for months to a year after giving birth. Experts believe this is a biological safeguard - small fat stores act as an energy reserve to support milk production and regulate the return of fertility.

   
   

5. Not getting below your pre-pregnancy weight

   You may find that weight loss gets harder the closer you get to your baseline (pre-pregnancy) weight. This is normal and has a very important physiological reason. For most women, the body naturally resists going under its pre-pregnancy baseline because the mobilization of older fat stores would increase the amount of pollutants in the blood and breast milk. Fat stores from before pregnancy often contain higher amounts of pollutants and toxins accumulated over the years, so the body is slowing down weight loss to prevent any adverse effects (source).

   
   

👉 In other words, it’s normal if your body prioritizes recovery and milk supply instead of rapid fat loss.

What’s Not Normal

If weight gain feels out of proportion - or doesn’t respond to healthy habits - there may be more going on. Let's dive into what I'd consider not a normal response to postpartum weight loss efforts:

• Consistent or unexpected weight gain

  If you're consistently gaining weight despite balanced eating and gentle activity, it's worth digging deeper.

  
  

• Extreme hunger or cravings

  Some hunger is normal, but if you're ravenous or craving sugar/sweets all the time - even after balanced meals - it could signal hormonal imbalances like insulin resistance or thyroid issues.

  
  

• Fatigue that feels out of proportion

  All new moms are tired, but if exhaustion is overwhelming, persistent, or comes with symptoms like low mood, brain fog, or weakness, it may point to thyroid issues, anemia, nutrient depletion or postpartum depression. Either way, it needs to be addressed.

• Losing your milk supply

  While slight dips can happen with illness, stress, skipped feeds or even starting your period, a sudden or ongoing drop in your milk supply is not normal and may be the result of restricting calories too much, dehydration or even medical reasons.

• Very rapid weight loss

  Crash dieting or cutting calories too low can stress hormones, reduce milk supply, and set you up for rebound weight gain - this is not normal or sustainable. It could also have physiological reasons. Either way, losing weight too fast is something that should be investigated.

  
  

• Not losing weight despite healthy habits

  Studies show most moms lose a majority of their pregnancy weight within the first year. If weight hasn't shifted at all despite healthy habits, further investigation is needed.

📌 Takeaway:

Not all weight challenges are “just the way it is.” If you’re experiencing unexpected weight gain, persistent fatigue, losing your milk supply, or struggling despite healthy habits, it’s worth investigating. As a Registered Dietitian and Certified Lactation Counselor, I can help with that!

My own weight loss story: This is me, 10 months after Baby#2 and back to my pre-pregnancy weight.

How to Reset

If you’re gaining weight while breastfeeding - or just not losing - it doesn’t mean you’re doing something wrong. The reset isn’t about dieting harder or exercising more. It’s about supporting your body’s recovery, balancing hormones, and protecting your milk supply while making gradual, realistic changes.

1. Reset with Nutrition

   
   

   • Build balanced plates: Use the breastfeeding plate method: ½ fruits and veggies, ¼ protein, ¼ whole grains/starchy veg, plus healthy fats.

   • Prioritize protein: Aim for 20 to 30 g of protein per meal to support satiety, muscle recovery, and stable blood sugar.

   • Smart snacking: Pair protein + produce + healthy fat (e.g., apple + peanut butter, Greek yogurt + berries).

   • Hydrate wisely: Aim for ~16 cups/day (water, milk, herbal tea). Thirst is often mistaken for hunger.

   • Micronutrient support: Keep up with a high-quality postnatal multivitamin containing vitamin D, iodine, selenium, and iron, if needed.

     
     

2. Reset with Lifestyle

   
   

   • Protect your sleep: You may not get 8 hours, but “banking sleep” early in the night, napping when possible, and asking for help with one feeding can reduce fatigue and cortisol.

   • Gentle activity: Focus on walks, stroller time, light resistance bands, yoga, or core/pelvic floor work once cleared. Small movements add up (NEAT = non-exercise activity thermogenesis). Excessive exercise can sometimes do more harm than good.

   • Stress management: Magnesium-rich foods (pumpkin seeds, leafy greens, dark chocolate), balanced breakfasts, and limiting excess caffeine help regulate stress hormones.

     
     

3. Reset by Checking the Medical Side

   
   

   If weight challenges come with red-flag symptoms, bring it up with your provider:

   • Thyroid function: Postpartum thyroiditis, hypothyroidism.

   • Insulin resistance: Especially after gestational diabetes.

   • PCOS: Can resurface postpartum.

   • Medications or contraception: Some antidepressants, corticosteroids, or hormonal contraceptives may influence weight.

     
     

4. Reset and Understand Your Hormones

   
   

   Your body is designed to prioritize your baby and your recovery:

   • Prolactin → increases appetite.

   • Cortisol → rises with stress/sleep loss, encouraging fat storage.

   • Leptin & ghrelin → disrupted by poor sleep, making hunger harder to manage.

   • Insulin resistance → common postpartum, slowing weight loss.

   • Estrogen & progesterone drop → change fat distribution and fluid balance.

   
   

   👉 Don't fight biology. Instead, work with your body by implementing various hormone-balancing and hormone-supporting nutrition and lifestyle strategies.

   
   

5. Reset Your Expectations

   
   

   • Losing 0.5 to 1 lb/week is safe once supply is established.

   • Your body may hold on to 5 to 10 lbs until weaning - and that’s normal.

   • Pre-pregnancy weight is not always your healthiest baseline; focus on energy, mood, and supply, not just the scale.

     
     

   📌 Takeaway: Resetting isn’t about restriction - it’s about balance. By focusing on nutrient-dense meals, realistic lifestyle changes, and checking for medical or hormonal barriers, you can feel better, protect your milk supply, and see steady, healthy progress.

👉 Ready to take the guesswork out of it? My 4-Week Breastfeeding Meal Plan was designed to do exactly this - help you reset - with recipes, grocery lists, and prep tips created for nursing moms.

The Bottom Line

If you’re gaining weight while breastfeeding, you’re not alone - and it doesn’t mean you’re doing anything wrong. Breastfeeding isn’t a guaranteed fat-burner, and many other factors (sleep, stress, hormones, thyroid health) play a role.

By taking a balanced approach - meeting your nutrient needs, gently adjusting calories, managing stress, and checking for underlying issues - you can support both your recovery and your long-term health.

👉 Ready for a done-for-you plan that protects your milk supply while helping you feel your best? Explore the 4-Week Breastfeeding Meal Plan.

About the Author

This article was written by Marina Lane, a Registered Dietitian and Certified Lactation Counselor with a passion for helping moms nourish themselves and their babies. As a mother of two who were both breastfed until age 3, Marina combines professional expertise with personal experience to provide evidence-based advice and support to breastfeeding moms. With her background in nutrition and lactation, she offers practical, science-backed insights to help you navigate your breastfeeding journey with confidence.