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by Stephanie Margolis, R.D.
updated February 23, 2023
Fasting is not something new, it has been part of many religions and cultures for centuries. However, the popularity of intermittent fasting with some recent research shows the health benefits. Intermittent fasting can be a great tool for moms who are trying to lose weight and improve their health. Let’s dive in to what it really means to intermittent fast.
Note: The information listed below is not specific to breastfeeding or pregnant moms. For more nutrition guidance, visit our breastfeeding or pregnancy nutrition articles.
Intermittent fasting isn’t just promoted by companies or influencers – it has been studied and promoted in a lab setting. In both lab rat and human studies, scientists have documented changes in weight status, glucose regulation, lipid (HDL, LDL, cholesterol) profiles, and inflammatory markers. These are all ways to measure one’s health and disease risk.
When fasting we seem some changes in the body rather quickly. In the short-term (22 days to 5 weeks), many studies showed insulin levels decreasing, HGH (human growth hormone) levels increasing, and cell repair happening. It is noteworthy that the HGH increased dramatically in several studies, because this hormone naturally helps the body promote fat loss and increase lean muscle.
Additionally, when the body is fasting the gut and cells can rest and repair, improving the gut microbiome (strongly linked to improved overall health). In the longer term, intermittent fasting has been linked to lowered inflammatory markers, improved brain health, and slowing of the aging process in both animals and humans.
Fasting consists of restricting calorie intake during certain times (fasting) and consuming food during certain times (feeding). These fasting and feeding times are cycled and do not focus on WHAT you eat but WHEN you eat. There are three main types of fasting (outside of religious fasting) that have been studied: alternate day fasting, modified fasting, and time-restricted fasting. Let’s take a glance at the details and study results of each type.
ALTERNATE DAY FASTING
What’s involved? Limited calories on fasting days. On feeding days eat as desired. Alternate days.
Study results*: This type of fast resulted in modest weight loss and improved metabolic profiles. However, participants reported extreme hunger, so the ability to adhere to this schedule long-term is questionable.
MODIFIED FASTING
What’s involved? On fasting day, participants would eat about 20 – 25% of their prescribed caloric intake (about 500 calories). On their feeding days, they would eat to their set calorie limits (e.g., 2000 calories).
Study results*: In modified fasting, there was consistent weight loss in all studies, but the effect on insulin regulation, lipid profiles, and inflammation markers were mixed.
TIME-RESTRICTED FASTING
What’s involved? This type of fasting is done daily and required participants to fast during certain hours of the day. The fasting periods in these studies ranged from 12 – 21 hours.
Study results*: This type of fasting saw the most consistent and positive results. Participants lost weight, improved their metabolic profiles, reduced their risk for obesity, and decreased their risk for diabetes and some cancers.
*These findings are a summary of 16 studies.
Intermittent fasting doesn’t mean restricting what you eat — though I always encourage you to make healthy decisions — but rather the window in which you eat it.
The most popular ratio for this format is 16 hours of fasting and 8 hours of feeding (commonly referred to as the “16:8 Method”). This looks like a feeding window from 8 a.m. – 4 p.m. or 9 a.m. – 5 p.m. or 10 am – 6 p.m. as it is the most realistic for moms on typical schedules. But the ratio you land on is highly dependent on your body, daily routine, and nutritional needs.
You’ll want to start slowly and work your way up to a longer fast over a few weeks. If you aren’t already there, aim for a 12:12 ratio. If you eat breakfast at 7 a.m., close the kitchen by 7 p.m. Then see if you can shave some time on either end incrementally.
Just how many meals should you be consuming? In an eight-hour window, 2 – 3 meals and 1 snack is probably sufficient. Of course, you can (and should!) have water throughout the day. You can also have black coffee and plain tea outside of your window. Again, while the studies don’t focus of the type of calories of are consuming it bears repeating that you should continue to eat a balanced, wholesome diet within the feeding time frame.
When we really look at time-restricted fasting, the research has shown that consuming energy earlier in the day, combined with nightly fasting, can give you the best results. There are several reasons why:
Luckily, you can reap the benefits of intermittent fasting without much effort. For busy moms, the 16:8 method is usually easy to incorporate and provides great benefits for your health and weight loss goals.
You know when you are exercising regularly and eating well but can’t seem to lose weight? Intermittent fasting can be a great way to jumpstart weight loss or break a plateau. Here are the factors that contribute to this success:
And the best part is that intermittent fasting doesn’t have a bunch of rules about cutting food groups or purchasing expensive “health” products. It’s not a diet at all. It’s simply about creating structure. It doesn’t impact what you eat, just when you’re eating it. So, as long as you continue to focus on making healthy choices about what you eat (read: limiting your intake of processed foods), it can help jumpstart weight loss.
It’s a myth that you need breakfast immediately when you wake up, or that it helps with weight loss. In fact, extending your fast a couple hours into your day can help your body dig into your fat stores and boost weight loss. My advice? Drink a cup of water immediately upon waking up. This should curb cravings and give your body the hydration and energy you need to start your day. And simply eat breakfast within 2 – 5 hours of waking.
Unless you’re planning on a high-intensity workout at least 50 minutes in length, you should have enough glycogen stored in your body to fuel your workout. If you work out for more than 50 minutes, you will need additional fuel or your workout could suffer. You can need to consider adjusting your window, changing your workout time, or choose to not intermittent fast. If you find it difficult to get through your workouts, feel free to ease into the schedule. Perhaps you wait until 7 a.m. one morning to eat. Then, after a few days, push it to 8. Within a week, you should feel comfortable starting your eating window at 9 or later.
Intermittent fasting can have many health benefits beyond weight loss, especially time-restricted fasting. Eating your food earlier in the day and allowing your body at least 12 hours to rest has been proven to improve your current and future health. While these studies only focus on the “when” of eating, we can’t forget about the WHAT. Choosing foods that are wholesome, unprocessed, and filled with vitamins and minerals is best. Our Moms Into Fitness Recipe Box is full of delicious ideas the whole family will love.
Intermittent fasting is perfect for busy moms. But moms that are breastfeeding or pregnant should not restrict their eating. You need the extra nutrients and calories to feed your baby!
If you have any hormonal issues or autoimmune disorders, speak with your doctor first. It’s possible that women have an increase, decrease or disruption in hormone production. If that’s your case, we recommended trying intermittent fasting every other day. As with everything … there is no one size fits all.
Also, there isn’t enough research to suggest this eating schedule is safe for kids. Plus, if your kids are anything like mine, they eat all day!
As always, speak with your healthcare provider before making significant changes to your diet.
