Intermittent Fasting While Breastfeeding: Is It Safe?

You’re in love with your sweet new baby, but you’re still struggling to adjust to your postpartum body. Maybe you’re even looking at ways to lose the weight you put on while pregnant.

When it comes to weight loss, you may have heard about the possible benefits of intermittent fasting. This eating style, which involves alternating between periods of eating and fasting, has been shown to help with weight management, along with other benefits like decreasing inflammation and improving gut health.

But when you’re breastfeeding, you’ve always got to ask yourself one critical question: “Is this safe?”

Let’s get to the answer you’re looking for upfront: “I do not advise intermittent fasting for parents who are breastfeeding,” says registered dietitian Julia Zumpano, RD, LD.

But why is that exactly, and what can you safely try instead?

Is fasting safe for you and your baby while nursing?

You shouldn’t try intermittent fasting (or any type of fasting) during the very active breastfeeding period when your baby relies on you as their main source of nutrition. It cuts down on the number of calories you’re getting, which can affect both you and your baby.

This is a time when you need more calories, not fewer. If you're breastfeeding, you should consume an extra 350 to 500 calories a day to help fuel both you and your little one.

“When you’re breastfeeding, your body needs more calories than usual because those calories go toward providing nutrients to your baby,” Zumpano explains. “When you’re low on calories from fasting, it can affect your milk supply and energy level — both of which are not good for nursing parents.”

In the later stages of breastfeeding, when your baby has begun to eat other foods, Zumpano says intermittent fasting may be safe to try.

“If you’re just breastfeeding in the morning and evening and you’re not the primary source of your baby’s nutrition anymore, then you could probably incorporate some fasting toward the very tail end of that breastfeeding period,” she adds.

But you should always check with your healthcare provider before starting any kind of dietary overhaul — especially while you’re nursing.

Safer alternatives for postpartum weight loss

It’s OK to want to try to lose weight after pregnancy, but first things first: Be kind to yourself. Giving birth and caring for a baby is hard work, and you’re likely in the midst of an incredibly busy, emotional whirlwind — which is just another reason that it’s not the right time to try to completely overhaul your wellness habits.

“When you’re breastfeeding, your safest bet is to focus on a healthy diet and exercise plan,” Zumpano relays.

A healthy breastfeeding diet should incorporate a variety of nutritious whole foods, including those that can help you maintain your energy and even increase your milk supply. Turn to staples of the Mediterranean diet, like:

• Whole grains
• Leafy greens
• Lean proteins like salmon, grass-fed beef and eggs
• Beans and lentils
• Nuts and seeds
• Greek yogurt

“The Mediterranean diet is a healthy overall style of eating,” she notes. “It focuses on whole foods that are largely familiar and accessible to everyone, including nursing parents.”

Maybe you’ve also heard that breastfeeding itself can help you lose weight. It’s not the case for everyone, but studies show that women who exclusively breastfeed may return to their pre-pregnancy weight slightly faster than those who don’t.

Talk to your doctor before starting intermittent fasting

It may be tempting to try intermittent fasting, especially when you hear hype about its possible health benefits. But for the safety of your health and your baby’s, skip it until you’ve weaned your baby from breastfeeding.

Even then, it’s important to talk to a healthcare provider before you try this or any new diet. Intermittent fasting isn’t right for everyone: It can impact your hormones and may bring side effects like fatigue, insomnia, irritability, headaches and nausea.

“Intermittent fasting is a popular eating plan that may be able to help you lose weight after you’ve given birth,” Zumpano states, “but wait until you’re done breastfeeding to consider it, and always talk to your doctor first to be sure it’s safe for you.”