Fasting, Chrononutrition, And The Breakfast Debate

Breakfast isn’t just a meal choice; it’s a timing decision that can shape your energy, hunger, and results all day long. 

We dig into why skipping breakfast often backfires, how circadian rhythms influence metabolism, and what the science of chrononutrition says about front-loading calories versus eating late. You’ll hear the real tradeoffs behind fasting strategies, from early time-restricted eating to late-night windows, and how each affects blood sugar, appetite regulation, and sleep.

We walk through the metabolic edge of daytime eating, including the thermic effect of food and the hormonal patterns that favor morning and midday meals. More importantly, we unpack behavior: how a simple, protein-forward breakfast can curb food noise, support training intensity, and reduce the urge to raid the pantry at 9 p.m. 

If you’re managing insulin resistance, prediabetes, or type 2 diabetes, we explain why back-loading calories can compound problems and how shifting intake earlier can help. Fasting isn’t the villain here; misaligned timing is. Used wisely, fasting becomes a tool that fits your life and biology.

You’ll leave with practical tactics: choose an earlier window, keep evenings light, and build a modest breakfast that’s nutrient dense without being calorie heavy. Track more than macros, monitor energy, cravings, sleep, and mood to see what truly works. 

If medications or health conditions complicate timing, check with your clinician before making changes. Ready to experiment with an eating window that works with your body instead of against it? 

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Peace, love, plants!
Dr. Jules 

Transcript

Section A

SPEAKER_00 0:10

Yo plant-based buddies, welcome back to Fuzzle Three of the Podcast. This video is going to be amazing. We'll be talking about all of the different pillars of lifestyle medicine, from nutrition to exercise to stress to sleep, and everything in between. Yo, plant-based buddies, welcome back to another episode. Today we're gonna be talking about skipping breakfast. I know it doesn't sound as scientific as other episodes, but with fasting that has kind of become one of the most talked-about strategies in nutrition over the last few years, I think it's very important to talk about the nuances of fasting, aka early time-restricted eating versus skipping breakfast and late time restricted eating, and the impact they all have on our health. I know if you scroll through social media or you listen to a podcast, you'll probably quickly hear about fasting, and people kind of skip breakfast and try to create a calorie deficit, and it ends up backfiring. Now, for a lot of people, maybe skipping breakfast is their way towards better health, but I just want to put a disclaimer on that blanket statement that fasting through skipping breakfast is going to create a calorie deficit for everyone. Now, in research studies, those who fast who have a more narrow eating window, they do typically end up eating less calories overall over the course of a full day. But that's not the case for everyone. And a lot of people report when they skip breakfast, they feel unwell. And what happens is that they tend to make poor nutrition quality choices and maybe even overeat calories at night. And what the scientific literature shows is that when people do not eat breakfast and ingest more or most of their calories later in the day, they typically eat in misalignment with their circadian rhythm. Now, for some people, fasting does exactly what it's supposed to do. It reduces total calorie intake, and it feels simple. Rigid rules for some people kind of work, right? People know that they're just supposed to eat from noon to 10 over a 10-hour window and have a 14-hour fast. Well, they end up eating fewer meals, they make fewer decisions around food, and it helps them lose weight. But simplicity doesn't always mean you're doing what's optimal. Now, and as fasting will grow in popularity across time, more and more people they've kind of made breakfast the first meal they cut very often because it's the simplest. And that decision just deserves a closer look and we need to talk about it. Now, regularly eating breakfast has actually consistently been linked to better appetite regulation for the rest of the day. And we know that people who eat in the morning, they often experience fewer extreme hunger swings later on. Blood sugar control seems to be more stable, the fatty acid metabolism looks more efficient. And these aren't just small details that can actually shape how the rest of our day unfolds and whether or not we feel we can exercise and how we sleep and how many calories we eat at night. Now, there's a metabolic component to the conversation that needs to be discussed. The body doesn't just process food the same way at all times of day. I've done a full episode on chrononutrition, which is really reasonable if you go take a look or take a listen if you haven't done so already. Calories eaten in the morning, even if absorbed the same way calories are absorbed at night, they're not processed the same way. Hormones matter, our circadian rhythms matter, and calories at night will not be processed in the same way as calories earlier in our day. Because earlier in our day, our metabolism is generally more responsive. Now, one reason for this is something called the thermic effect of food, and this refers to the energy your body spends digesting, absorbing, and metabolizing what you eat. And what's interesting is that the thermic effect of food is slightly higher in the day than it is at night. And that difference is typically influenced by your circadian rhythms and all of the hormones that are involved. These hormones that are involved in metabolism, in digestion, and energy use, they follow a daily pattern that favors daytime eating. And when you're eating most of your calories earlier in the day, you're eating in alignment with your hormones and with your circadian rhythm. Now, this concept is called chrononutrition and it doesn't make front page news, but it is an important concept to be honest about. And honestly, when talking about the thermic defect of food, the difference is in thermic effects between morning and evening meals. They're relatively small, so I'm not talking about any magical calorie-burning trick. But it does matter and it adds to a broader picture that supports front-loading your calories earlier in the day than pushing most of that calorie intake into the evening. Now, what's even more compelling is not a piece about metabolism, but what breakfast actually does in terms of behavior. People who do fuel themselves in the morning, they feel more energetic, they move more, they tend to have higher needs, they exercise with more intensity, and they make different food choices later in the day. And this applies to a lot of people. Not everyone, but many people report this. And not for everyone, but for some, skipping breakfast, it actually sets up a very different type of pattern. Their energy dives earlier, their stress hormones could rise, and hunger can build up during the day, kind of in the background, and by late afternoon or evening, the appetite or food noise feels louder and harder to manage. And people make in the presence of food noise, they make less healthy choices for the most part. And this is kind of where the whole concept of fasting gets misunderstood. Now, fasting itself, that's not the problem. But for some people, it can be a great tool. It could be an effective tool to lower the amount of calories in your diet, but you need to know what could happen. Now, very often I will fast and skip breakfast on purpose, just to reduce calorie intake when I was, for example, cutting calories before World Ninja Championships. For those who don't know, I've competed three times at the World Ninja Championships in Orlando, Vegas, and in LA. One of some of the best experiences of my life, my sport, sport of Ninja Warrior, is a sport of strength-to-weight ratio. The stronger you are, to carry the body you're living in, right? So sometimes I did absolutely fast on purpose, not because of autophagy or inflammation, because I simply wanted to cut calories and I did skip breakfast. And what happens then is I felt a tenfold ramp-up of my appetite and salt craving later in the day. If you would have put a bag of pretzels on the table, there is no way I would have had the willpower to resist it. But I recognized that of my metabolism very quickly, where I just kind of craved ultra-processed carb-rich, salty foods. And that was probably more just my hunger signals, and maybe I was dehydrated because of the fast, although I did drink a lot of water. But it just kind of backfired for me very often. The days where I didn't have any willpower, the kind of skipping the breakfast in the morning just kind of brought me nowhere. It ended up, it ended up backfiring, and I end up eating more calories at nine. Now, but I know that now. So if ever I'm in the same situation, I know what to do to avoid that. Or if I am educated about I am going to be reacting this way tonight, I'm going to be craving a lot of calories, I just make sure to kind of have a strategy in place so I don't overeat, right? Now, for other people, the metabolic downside is that if patients, if you're someone who already living with resist uh insulin resistance or you have type 2 diabetes or you're prediabetic and you decide to skip breakfast, there's always that chance that if you instead of front loading your calories, that you eat most of your calories at night, that insulin resistance will actually get worse. Because if your sleep is disrupted and your hormones are all out of whack and out of line with your circadian rhythm, your body at 11 p.m. while you're craving ultra-processed food is not ready. And the hormones are not optimally geared to metabolize carbs and process energy, right? So insulin resistance can actually get worse. And that kind of backloading to the back of the day your calories can actually end up kind of neutralizing any possible benefits, not only from the fast, but from the calorie deficit itself. So, but fasting is not the problem, it's just it's much more nuanced than that, right? Now, I have already done an episode on fasting in season two. I explained that fasting is an umbrella term and includes prolonged fasting and alternate day fasting and intermittent fasting and 5-2 fasting and time restricted eating that could be either early or late time restricted eating, and even the fasting mimicking diet. Now, fasting is simply a word that talks about reducing calorie intake or calorie eating window, and there are a million different ways to do it, right? And there are probably benefits for the most part of early TRE, early time restricted eating that go beyond just the benefits of the calorie deficit, right? So fasting isn't a problem, it's understanding that it can work and be beneficial for certain people if certain rules are met. Now, a physiologically aligned approach to fasting is often not skipping breakfast, but actually stopping food intake earlier in the evening. Now, this better aligns with your circadian biology. Insulin sensitivity is usually higher earlier in the day, and then it's easier for your body to handle glucose. It's like the body is more prepared to process energy. But late-night eating, it actually pushes calories into a type of biological environment that is shifting towards rest and towards repair and not digestion and processing and storage of energy. Now, when we look at people who actually achieved long-term sustainable weight loss, there's typically a consistent pattern that shows up. And most of these people are typically not people who skip breakfast. They eat regularly, they fuel early, they maintain structure and front-load their calories. That doesn't mean that breakfast has to be large or elaborate. It doesn't mean that fasting never works. It means that being consistent and fueling during the morning and aligning your calorie intake with your daily rhythms seems to support lasting success more than relying on routinely delaying food or skipping breakfast and eating later in the day. But this episode was not about rules, it's about working with biology instead of working against it. So While fasting could be a useful tool for some people, skipping breakfast is not always the best approach. And regularly eating breakfast is just associated with better appetite regulation, more stable energy, and improved metabolic function and outcomes. The body processes food more efficiently early in the day, period. And front loading your calories often supports making better choices in terms of movement and mood and food choices for the rest of the day, including the night. Long-term weight loss success tends to favor consistency and morning fueling rather than skipping breakfast. But if your goal is weight loss or weight management and energy deficits are one of your objectives, maybe experimenting with eating earlier rather than delaying food until late afternoon could could work for you. I mean, I know that skipping breakfast is for a lot of people just easier in terms of willpower than not eating late at night. But be mindful that it probably is going a little bit against your biology. You can still keep your breakfast simple, you can make it rich in protein and still low in calorie. It doesn't need to be large to be effective, it just needs to be nutrient dense. And very often, if I am to try to aim for a calorie deficit, I'll have a green smoothie with protein and veggies and nuts and seeds, but just sprinkle so I get some nutrients in me without being over the top in calories. Now, if you decide to skip breakfast, just notice how doing this affects your hunger later in the day, not just your appetite in the morning. For me, skipping breakfast is very often a tool I use. I understand the detriments to my metabolic health. Should I be to overeat at night? So very often, even when I skip breakfast, I still try to eat a nutrient-dense meal for supper and not eat in the evening. And if you're using fasting, just consider maybe ending it earlier in the evening instead of skipping breakfast. But make sure to pay attention to your energy, your mood, your movement, not just calorie intake. And for a lot of people, skipping breakfast on purpose is really just not healthy. They're taking glycations like hypoglycemic medication for diabetes, they're taking antihypertensive for the blood pressure, they're taking certain medications that cause an upset stomach when taking on an empty stomach. So, like always, I want to make sure that understand that I'm not making any medical recommendations here. I'm producing content to help you educate yourself so that you can bring some of these topics to your healthcare professional to make an individualized recommendation inside of the office of your doctor. I'm not telling people to skip breakfast or to not skip breakfast. It could actually backfire depending on your context and your medical conditions. But for long-term success, you need to be consistent in whatever you're doing and just have regular meal timing. It often matters more than being perfect with your macronutrient ratios. Breakfast isn't mandatory for everyone, but for many, just lays the powerful foundation that impacts all of the choices they make throughout the rest of the day. And that was the experience I had. And I use this tool wisely now, the tool of fasting, because I know that my appetite will ramp up. And if I'm having a low willpower day and I do have access to ultra-processed foods, they're in for a beating. So yeah, so just make sure that whatever you're doing, you're just journaling, you're monitoring, you're reflecting on how you feel. Because people just they just go through life without asking themselves any questions. And before you know it, the what was supposed to be a routine optimizer, like skipping breakfast in terms of creating a calorie deficit, ends up backfiring and kind of neutralizing or annihilating any possible benefit from the calorie deficit, right? I mean, what good is a calorie deficit created in the morning if you're gonna overeat at night and create insulin resistance and increase cortisol levels and have super high levels of ghrelin and low levels of leptin the next day, which makes you overeat. I mean, clam gone bad. Right on. I hope this makes sense. Basically, what I'm saying is that skipping breakfast is a tool very commonly used in the fasting movement, but I'd much rather see people use fasting in a responsible way that is aligned with their biology and aligned with their circadian rhythms, and that's just that's not just my opinion. It's actually based in high quality evidence. Cool. Right on. Hope this makes sense. Hope you like this episode. Thanks for tuning in. We'll see you the next one. Everyone, go check out my website, plantbasedrjewels.com, to find free downloadable resources. And remember that you can find me on Facebook and Instagram at drjoulescormier, and on YouTube at Plantbase Dr. Jewels.