Intermittent Fasting and Skipping Breakfast: What the Research Says (Episode 522)

Full Transcript: Episode 522

Lisa Hendrickson-Jack:

In today’s episode, we’re diving into the topic of intermittent fasting and asking an important question — does breakfast count as intermittent fasting? And since this is part of the FAMM Research Series, I’m going to be going through a really interesting study that looked at the impact of skipping breakfast on your total meal consumption, total caloric consumption for the day, as well as its impact on exercise. So without further ado, let’s go ahead and jump in.

So today’s episode is inspired by one of the sections in our newest book, Real Food for Fertility. In the second chapter, Lily covers the macronutrients in great detail — the importance of consuming sufficient protein, fat, and carbohydrates in balance. We go through the plate method, and we also talk about intermittent fasting, and we share our take on whether or not we think this is a good idea. In the chapter, we break down different kinds of intermittent fasting. Some people will eat one meal a day and that’s what they call intermittent fasting. Other people may just shorten their eating window. So instead of eating whenever they want, maybe they’ll eat within a six-hour window that day, or an eight-hour window, or a ten-hour window. And then basically the bottom line is that there are different ways to do this.

What our recommendation is, if you are considering intermittent fasting, would first of all be to really consider why you’re doing it. There are certain situations where intermittent fasting can be helpful and beneficial, especially for somebody who’s struggling with insulin resistance or kind of somewhere on that PCOS spectrum. So we share some interesting data there. But for many women, they’re wanting to lose weight. And again, it really depends on what your goals are. If your goals are to conceive and to optimize your menstrual cycle health, then we really want to encourage you to approach intermittent fasting very carefully.

And so our recommendation is, if you’re planning to consider or already doing intermittent fasting, to give yourself a decent eating window — say 10 hours. And we recommend consuming three full meals per day during that eating window. So essentially, we’re recommending that you eat a full caloric spread over that period of time. And so one way to do that would be to have three full meals and no snacks within a ten-hour eating window. The goal from our perspective is that you’re not reducing your caloric consumption. So you’re not dieting — you’re just changing when in the day you’re consuming the food. So instead of just eating whenever and snacking throughout the day, if you’re going to do it, do it that way. And the reason why we do that is because of what we’ve seen clinically, what we’ve seen in the menstrual cycle — how it affects women, how it affects their hormones, how it affects their ovulation and their progesterone production and so on. But also what it says in the research. And so that brings us to today’s study.

The names of these studies always leave something to be desired — it’s like a super long name. But basically it’s looking at how skipping breakfast impacts your overall energy intake and physical activity. That’s the summary of the title. And if you’re wanting to grab the link to the study itself, you can head over to fertilityfriday.com/522 and you can find that information there.

So basically, in this study, what the researchers did is they gathered 20 women who were lean and between the ages of 20 and 25 — so likely college student age. And what they did was they had them do different things on different days. Either way, there were days when these women were eating breakfast and days when they were not eating breakfast. On the days that they ate breakfast, they had them come into the facility and eat breakfast at 8:00, then instructed them to eat lunch at noon, and then have their dinner later on. In the group that did not eat breakfast, they would simply give them water at 8:00 in the morning and then instruct them to have lunch and dinner. And they measured their total caloric intake for the day.

And this study is really interesting and helpful. I find it to be useful when talking about the concept of intermittent fasting because you would think that if you skip breakfast, then when you eat lunch you’re obviously going to be really hungry. So you would think that at lunch you would make up for it, or between lunch and dinner you would make up for it. But what’s interesting is what the researchers found was that when the women would skip breakfast, they would eat more at lunch — but they wouldn’t really eat more for the rest of the day. So dinner and snacks after lunchtime were basically the same between those who had eaten breakfast and those who had not. And the amount that they ate at lunch, obviously it was more than what they would have eaten otherwise, but it still didn’t offset the total amount. So they never ended up eating as much as they would have if they ate breakfast. That’s a huge takeaway from the study. And I feel like that is what you see in real life — you kind of think you would eat way more food, but there is kind of a limit to what you are going to eat during that period of time. And that’s what it showed in the research.

Another interesting finding was that women who skipped breakfast — and this is something that the researchers kind of alluded to that’s been shown in other research as well — it did have an impact on their physical activity in the morning. So they also found that when you skip breakfast, you weren’t necessarily as active in the morning. And I suppose that makes sense if you think about it, because if you’re not eating as much, maybe you don’t have as much energy. So it didn’t necessarily affect their activity level throughout the rest of the day, but certainly in the mornings they tended to have less physical activity.

Another interesting finding is that when they looked at the macro breakdown of the food consumption, specifically the women who skipped breakfast had an overall lower consumption of carbohydrate and protein for that day compared to those who had eaten breakfast. And I suppose that could just indicate that maybe the lost opportunity from breakfast — what they would have eaten, their protein intake and what that would have been — because it was missing, they just never made up for it.

So a couple additional interesting pieces of data from this study. The researchers found that the women in the study had 26% of their overall caloric intake actually come from breakfast. So from that standpoint, that’s like a quarter of their total intake for a day. It’s pretty significant. And they compared it with other research, and other studies have found maybe closer to 20%. But what we can take from that is anywhere from a fifth to a quarter of our total caloric consumption comes from breakfast. And so when we skip breakfast and end up with just our meal for lunch and our meal for dinner, we are really missing out on an opportunity.

There’s lots of different research studies. I picked this one that focused on breakfast and its impact on overall caloric intake, and I picked it because this is one of the studies I pulled and spoke about in the section on intermittent fasting in Chapter 2 of Real Food for Fertility, because it does kind of illustrate this point that we think we’re just going to eat more later on, but it really doesn’t work that way.

But there’s a lot of other studies on breakfast. There are interesting studies showing that women who eat breakfast are less likely to have intense period pain. And there’s all of these kinds of things that you would think — how could one thing be related to another? But what I found consistently when working with women, working with clients, and working with our practitioners in our FAMM program is that when women start incorporating breakfast, it changes a lot of things hormonally. Especially when that breakfast is protein-rich. Front-loading protein at the beginning of the day is a game-changer in so many different ways. It increases energy. It supports hormonal health, so it can help to balance hormones, help to support progesterone production, improve luteal phase issues, improve overall energy. There’s just so many things that happen, especially when we’re charting the menstrual cycle and paying attention to how it fluctuates and changes. It’s actually mind-boggling how many things improve when we eat breakfast.

So you know, these researchers — what’s interesting about this particular study is they were searching this topic maybe for a different reason than I would search this topic. I would be searching this topic to find out why it is that women who skip breakfast have so much fallout in the menstrual cycle — why when I’m working with somebody and they have clear hormonal imbalances showing on their menstrual cycle chart, why adding in breakfast makes such a positive difference for them. However, these researchers were looking at this particular topic for a different reason. When they started, in their introduction, they highlighted some historical research that has found that women who skip breakfast have been found to have a higher BMI. So one of the reasons that they were looking at how eating breakfast would impact your overall caloric intake and your likelihood of exercise was related to them trying to solve this conundrum — how is it that women who skip breakfast are more likely to also have a higher BMI? And they were suggesting, well, maybe if you skip breakfast you’re less likely to have as much physical activity, and maybe that is predicting future BMI.

But interestingly, the study shows pretty clearly and consistently that the women in the study who skipped breakfast did not end up eating enough overall to offset it, and it did have somewhat of an effect on their physical activity — but particularly in the morning. For our purposes, our main goal, especially in writing Real Food for Fertility, was to support women to optimize their menstrual cycle health and hormone production so that they could then go on to optimize their fertility as well. And the best way to optimize your hormone health, your menstrual cycle, and overall fertility is to ensure that you’re actually eating sufficient amounts of all of the main macronutrients — protein, fat, and carbohydrates — in balance.

And what the research tells us is that sufficient protein is essential. It is one of the building blocks of our hormones. And sufficient fat is also essential, particularly animal fat, given that cholesterol is the precursor to our steroid hormones — estrogen, progesterone, testosterone, cortisol, and even vitamin D. So these are like pieces to the puzzle. We need to get the pieces, but we also need to get them in sufficient amounts. And what we’ve observed, and what the research would indicate, is that when we’re skipping meals, we’re not getting sufficient calories. And in a separate study that I’ve talked about on the podcast before — women who were eating 20 to 30% less calories, even if their cycles weren’t overtly disrupted, were still producing significantly less estrogen and progesterone. So we have enough data to support what we see in practice, which is that when women undereat — whether intentionally or inadvertently — it does have a negative effect on their hormone production.

And this is the heart of this. I feel like this study gives us some practical information because it’s telling us, okay, so I know it seems like it’s no big deal to skip breakfast once in a while, but from experience I know that many women just get into the habit of it. And then we haven’t even brought in the coffee part of the conversation, which is that for many women, drinking coffee first thing in the morning is what really helps them to overcome their hunger and wait on breakfast. It’s super convenient — if you don’t have to cook things or prepare things or grab things, you could just kind of get about your busy day. So I think many of us, out of convenience, fall into these habits. And then depending on which male influencer we’re following, we also think it happens to be healthy for us.

But my take on it has always been that women cannot approach health in the same way as men all the time. The things that may work for men in certain situations don’t always work for women. And arguably we don’t really know how well they’re working for the men, because they don’t have a menstrual cycle. And so we can’t really be so nuanced to see if it’s having some sort of effect. But on the other hand, men often benefit from intermittent fasting, skipping meals, one meal a day, whatever it is — in the sense that if they have weight goals or different goals for their body or fitness, often they’re losing weight faster and all that kind of stuff, because they’re different. Their metabolism is different. Their percent muscle mass is different. So we can’t always take the same approach as the men do, especially when we’re looking to optimize our menstrual cycle health, balance hormones, and optimize fertility.

So in conclusion, if you are thinking about intermittent fasting as a way to lose weight or whatever your goals are, then I would highly encourage you — if you’re also looking to optimize your menstrual cycle, optimize hormones, if you are planning to conceive in the near future or actively trying to conceive now — I would strongly encourage you to have a read through Chapter 2 of Real Food for Fertility, where we talk about intermittent fasting in more detail. And I would highly encourage you to consider, if you’re looking at intermittent fasting to support you, to help to balance and maintain blood sugar — whatever your goals are — I would highly encourage you to consider more than just the timing. Consider your macronutrient ratio. Consider making sure your meals are balanced and you are consuming sufficient protein and fat to support your overall hormonal health. And I would encourage you to eat breakfast and to aim for three full, good-sized meals a day so that you’re not inadvertently undereating.

And this is especially important when you’re also exercising, because it’s very common for women to inadvertently undereat when they’re also quite active. Men when they’re working out are typically trying to bulk up, so many men will go and consume additional protein and things to really help support building muscle mass. But for women, we are often trying to lean up. So it doesn’t occur to us to add in more food when we ramp up our exercise.

And all of these things can be easily identified and monitored when we track our cycles. So the good thing about this conversation is that we all have our vital sign that we can pay attention to. We can track our cycle and see how it’s affecting us. And then you can see definitively whether or not this approach is hurting you or helping you.

Again, if you’re wanting to take a peek at the study, head over to fertilityfriday.com/522. And you can also head over there and share this episode if you can think of someone who you think would really benefit from this information. The share link is fertilityfriday.com/522. If you’re loving the FAMM Research Series — this is the series where I go through specific, interesting research papers that I’ve looked at for one reason or another, often studies I’ve written about, or maybe they didn’t make it into the book but I found them to be really interesting — you can head over to fertilityfriday.com/research and you’ll get the full list of all of our research episodes.

So with that said, I hope you have a wonderful week or weekend whenever you’re tuning into the show, and of course, as always, until next time, be well and happy charting.