Eating One Meal a Day for 30 Days: Exploring Changes in Behavior and Physiology

The video discusses the potential effects of eating only one meal a day for 30 days. The speaker explains that hunger is largely based on habits and that the body has the ability to adapt to changes in eating patterns. He discusses how the body makes physiological changes at the cellular level to adjust to different behaviors and environments. The speaker also explains how the body burns carbohydrates before fat and that by eating less frequently or consuming fewer carbohydrates, the body can transition to burning fat for energy. He suggests that eating one meal a day can lead to weight loss, improved metabolic health, and increased energy stability. The video concludes by encouraging viewers to experiment with their eating habits and find what works best for them.

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How does this happen?

Key Insights:

  • Hunger is a sensation that is mostly based on habits and conditioned expectations.
  • Our bodies constantly adapt and make changes at the cellular level in response to changes in behavior and environment.
  • The biggest obstacle for most people to change is the belief that they are the way they are.
  • Eating habits can be changed and the body can adapt to eating once a day.
  • When eating once a day, the body initially uses stored glycogen for energy and then starts burning fat.
  • The body will primarily burn carbohydrates first because they are a less efficient storage form than fat.
  • Changing eating habits to once a day can lead to weight loss, improved metabolic health, and reduced risk of chronic degenerative diseases.
  • Eating once a day for 30 days can create new habits and rewires the nervous system to make it easier to maintain this eating pattern.
  • Longer fasting periods can be added to break through weight loss plateaus or improve metabolic health.
  • After achieving desired results, individuals can experiment with different eating patterns to find what works best for them.
  • Change is constant and easy, and individuals have the power to recreate themselves.


Hello Health Champions. What would happen if you only ate one meal a day for 30 days? Just once a day for 30 days. Well, a lot of people would probably say that they would get hungry. But what we want to understand is more about the changes and the behavior, the physiology of change that can assist us in making these changes.

So hunger is just a sensation, and it’s mostly based on habits. Whatever habits you have, whatever behavior you engage in habitually, creates a conditioned expectation. Your body is led to believe that things are going to happen a certain way. And your body adapts by making changes at the cellular level. It can increase and decrease physical tissues, make metabolic changes, upregulate or downregulate enzymes, hormones, mitochondria, and energy production, and even make neurological changes. Your body constantly makes new synapses and breaks down old synapses that you don’t need anymore. So it rewires your nervous system and your behavior and lays down physical pathways that are different.

The biggest obstacle for most people to change is that they think they are the way they are. That’s just the way I am, and my dad was the same way, and it runs in my family, and that’s the way we’ve always done things. But it doesn’t work like that. If you’re eating six times a day, it’s because you learned to eat six times a day. If you eat three times or once a day, it’s because you learned to eat that way, and your body started expecting it.

So what we really want to understand is change. Is change really difficult? And I want to make the argument that it is not hard. It is inevitable. It’s the only way it can be, constant change. You’re changing all the time already. So how come then, you say, that I look like the same person when I get up in the morning? And I look in the mirror, I see the same person that I saw yesterday or last week or last year, and it’s probably going to be the same person I see next week.

Well, here’s how it works. It’s not the same person looking back at you because you are 90 new cells since last year. The person you’re looking at today, versus last year, 90 of those cells are different. Old cells break down, and you have to make new ones. So if they look the same, it’s because you made more of the same.

The other way you want to think about this is that your nervous system is processing billions of bits of information every second. It receives information, processes information, and issues commands. It signals, orchestrates the body, and in doing that, it’s always changing and adapting. Every moment of every day, you are changing. Your body is reacting to the things you eat, your thoughts, the air pressure, gravity, and things happening around you. And if it looks like you are the same, it’s not because you stayed the same, it’s because you changed, but you recreated the same thing.

The way the body changes is called adaptation, and I love to observe these everyday things and really sort of think about them and be in awe of how incredible the body is. So one example is when I’m walking on the mountain trail and I have a heart rate monitor, and I look at the heart rate, and I’m walking on the flat. And then as soon as it starts going up even a couple of degrees, my heart rate goes up. Isn’t that incredible? There’s some intelligence in my body that knows that the conditions are changing, and we’re going to need more oxygen delivery, more blood flow to cope. So automatically, I don’t have to think about it. I don’t know how to do that. My body knows how to do that. It just blows me away. I’m in awe. I love to watch these things.

Then if you do things on a regular basis, now the body gets so good at it that it anticipates. You don’t even have to get up on the incline. It observes, and as soon as you get even close, your heart rate goes up a little bit, just in anticipation, just to be ready. If you do this and your body gets better at it, then you start creating long-term changes. So now we’re talking days to months.

One example is playing the guitar. I love playing the guitar, but the first time you pick it up or if you haven’t played for a long time, the first time you pick it up, it really hurts. It feels like your fingers are bleeding after just a few minutes. But if you keep it up, then after a few days or a couple of weeks, just any amount of regular playing, then your body puts down calluses, changes the skin, and it only changes it on one hand where you need it. How smart is that?

If you go to the gym and if you put some tension on a muscle, the body senses, „Hey, I’m gonna have to use more strength in the future.“ So it sends more protein to incorporate into more muscle fibers so it can get better. It’s called muscle hypertrophy. And the opposite is true as well because if you’re a couch potato and you don’t put any tension on your muscles, now the body says, „Why should I put precious protein resources into building tissue that there’s obviously no use for?“ That’s called atrophy.

If you’re working on your endurance, now your body increases your blood distribution capacity. It will make more blood capillaries. It will increase your red blood cells to increase oxygen delivery. It will upregulate enzymes involved in energy production. It will increase the number of mitochondria so you can make more energy and use more oxygen. There’s endless pieces that the body improves to make you better at whatever you do.

And if you normally live at sea level but then you go for a couple of weeks, maybe a vacation in the mountains, now at altitude, there is less oxygen in the air. If there’s less oxygen, the body senses that. It says, „I’m going to need more red blood cells. I need to increase my oxygen-carrying capacity so I can keep delivering the same amount of oxygen even though there is less of it.“ So your kidneys make a hormone called EPO or erythropoietin to make more red blood cells. How smart is that?

Bone is another interesting example because if you load up bone, if you do weight-bearing exercise under the influence of gravity, you’ll make more bone or you’ll maintain and reinforce the bones. Whereas if you go out into space for any length of time, then the body says, „Well, what do I need all these bones for because there’s no gravity?“ And NASA says that astronauts will lose 1% bone mass per month in weightlessness. That’s about 15 to 20 times faster than a deconditioned elderly person.

And another adaptation is insulin resistance. We talk a lot about metabolic health and insulin resistance on this channel because it’s related to weight loss and diabetes and so forth. So if you have chronically high insulin, your cells start to resist those high levels of insulin, and the cells become insulin resistant.

All of these are changes that you’re aware of, that you can see changing day to day. And if you were to eat once a day for 30 days, then your body would make similar changes relevant to your metabolic function.

But if we only eat once a day, one meal a day, where are we gonna get the energy? That’s what we’re told all the time, that you have to eat breakfast to give you energy up until lunch. You have to eat small frequent meals to keep your blood sugar up, otherwise, you become hypoglycemic, and your energy tanks. Well, that doesn’t really happen, right? Because the people who try eating one meal a day, they actually find that they survive and they feel better.

So here’s how it actually works. When you eat the food, that food that you just ate does not become energy right away. There’s a small trickle. You’re breaking down a little bit of glucose in the mouth. You start absorbing just a tiny little trickle. But the vast majority, 98% or so, of the food you ate is gonna become energy hours later.

So the way it works is the food that you just ate becomes a signal. It tells the body, „Hey, we have some resources coming in. You don’t have to hold on so tightly to the stores from before.“ So the body starts breaking down some glycogen for blood glucose. It starts breaking down some fat for energy so that we have some energy while this food is being processed. And then in the next couple of hours, you break down the food, and after a few hours, some of that food is used up as energy, and a lot of it becomes stored as fat and carbohydrate. Those are the two primary storage forms of energy in the body. Protein can become energy, but the body under normal conditions will spare the protein because it’s more important for other things.

But now that we have stored the fat and the carbohydrate, the whole idea would be to use up some fat and carbohydrate. But what happens is we’re going to primarily burn carbohydrate first, especially if we eat many meals a day and especially if we eat high carb. Then we’re going to store fat and carbs, but we’re going to burn the carbohydrate first primarily. I’ll get back to that and why the body is going to burn the carbohydrate first and have a tendency to do that.

There are two reasons. The first is that the body is very poor at storing carbohydrate. The vast majority of energy stores in the body is going to be fat, which is a much better storage form. If you’re a little bit on the obese side, you might store about 0.4% as carbohydrate. If you’re very lean, it might be 2% carbohydrate, but almost all your energy stores are going to be fat.

The other reason the body will burn carbs first is that high glucose levels are dangerous, not short-term, not for hours or a few days or even weeks, but if it goes on for years or decades, that’s called diabetes. Diabetes is the number one cause of blindness, kidney failure, neuropathy, joint destruction, heart disease, high blood pressure. All of those things are associated with high glucose. So the body is going to do the best it can to bring this glucose down anytime it gets high.

There are three ways that the body can reduce that glucose. One is that it can burn it. That’s why it tries to use carbohydrates first. Second, it can try to store it, but we already said that the carbohydrate stores fill up very quickly. The body is very limited in the ability to store carbohydrate. And the third thing it can do is to store fat. So now we’re back into storing fat and carbohydrate but mostly burning the carbohydrate.

So how would we ever get into burning the fat? We have to eat less carbohydrate and/or eat less often. It’s even more powerful to eat less often. So if you eat once a day, one meal a day, you go 20-24 hours without food, your body has to get into burning that fat because it will burn through some of that carbohydrate, and then it will switch, it will transition to have a tendency to burn more and more fat the longer you go.

And now that I’ve said all that, I want you to listen very, very carefully because these are not absolutes. We want to think in tendencies and percentages rather than absolutes because the body always uses a mix of carbohydrate and fat, always. But the mix is different. It’s going to be primarily carb or primarily fat. And here’s how you want to think about it.

Depending on where you are on the insulin resistance on your metabolic health, then you’re going to be either on the red side, if you are a high carb, diabetic person, or if you’re a metabolically healthy, low carb person, you’re going to be on this end. So if you’re eating maybe once a day and you’re eating very low carb, you’re probably going to burn about 95% fat when you get into the fat burning zone because you’re teaching your body to use fat primarily again, you’re shifting your metabolic pathways.

But if you’re eating all these carbohydrates, why don’t you burn 100% carbs? Why do you burn 30% to 50% fat? Because some of these carbs that we talked about, they get converted into fat. There’s always a flux, a transition of glucose becoming fat. Fat cannot become glucose, it’s a one-way street, a one-way trip. But glucose is always being transitioned, being converted into fat. And the more glucose we have and the more carbs you eat, the more of that conversion is going to happen. So a portion of your energy is always going to be coming from fat, even if you eat zero fat.

But who would not be a good candidate to eat one meal a day? Well, if you are too thin, if you are emaciated, if you are scrawny, if you have a really hard time putting on weight, then you’re not a candidate for this. I don’t do well eating one meal a day for very long. I do it a couple of times a week because of convenience, and I feel good doing that. I don’t have a problem. But if I eat one meal a day for a couple of weeks, then I start losing too much weight. It’s difficult for me to maintain that. So if you’re too thin, then you shouldn’t eat one meal a day.

If you are pregnant or breastfeeding, you are eating for two, and that’s not the best time to experiment. Your body, as you well know, is crazy enough with everything going on. So that’s not when you want to make changes.

If you are a small child or a growing child or teenager, then that also is not the best time to make far-reaching changes. Anything else? Well, it would be any kind of condition. If you have a digestive disorder, if you have anything else going on where you feel you need more, if your body isn’t ready to make those kinds of changes, just use your common sense.

So if you fit any of these, does that mean you have to eat six times a day? No. I would recommend that for most people, you can safely eat two to three times a day in a six to eight-hour period. And if you eat good, solid foods with a good mix of meat, vegetables, and fat, then you’re going to get plenty of nutrients to fill you up and sustain you.

So now that you understand the physiology of change and you know that you can do this, what’s going to happen if you eat once a day for 30 days? You will probably get some hunger and discomfort, and if you are a carb addict, if you’ve been eating six times a day, you might have more discomfort. If you’re metabolically healthy, you might have very slight discomfort. But the key to understand here is that it’s very short-term. Your body adapts physiologically very, very quickly. So we’re talking a few days, and then your body will be on track with your new habits.

And what you find then is you actually have less hunger because now you taught your body to burn fat, you taught your body to use the reserves more efficiently. And they often say that it takes 21 days to change a habit, and I don’t know if that’s a magic number, but I think it’s a good rule of thumb. So if you go 30 days, then you’ve got the 21 plus a little bit of extra, which means that you have probably created a new habit, you have rewired your nervous system. This is what your body expects now, and it becomes easier and easier to maintain it.

One of the most important changes you will probably see is a change in blood glucose and insulin. They will both have a tendency to drop, and they are related to something called Syndrome X or metabolic syndrome. That’s associated with the majority of degenerative diseases like type 2 diabetes, high blood pressure, cardiovascular disease, stroke. They’re all part of metabolic syndrome. And if you eat once a day for 30 days, you will start healing your metabolism, you’ll start teaching your body better metabolic habits, you will learn how to start using some of those stores, and you will be dramatically reducing your risk of chronic degenerative disease.

A lot of people will also start losing weight. Some people with the most stubborn weight may not see this immediately, but 80-90% of people will probably have a significant weight loss. And then we get into some of the quality of life, you will find that it’s a huge time savings if you’re only going to eat once a day. It doesn’t take that long, and you can also increase the quality of your food. You have time to create a gourmet meal every day, basically, because you’re only going to eat once. You can take the time to do that.

You’ll also find that because your metabolic health is improving, now you start burning some fat stores, your energy becomes more stable. You’re not dependent on topping off your blood sugar every couple of hours. Your mood improves. Your energy is much more stable. And because of this, you also find that you have more freedom because your life no longer revolves around a feeding schedule. You don’t have to structure your entire life around where am I going to find food. If you get to food, you eat. If you don’t, you’re going to be fine anyway.

So let’s say you do one meal a day for 30 days, then what? Well, it kind of depends on where you are, what were your aspirations, what did you hope to accomplish by doing this? If you’re done, then you can start playing around with some other things. But if you still have some ways to go, then you keep it up, you do another 30 days, and another 30 days, and so forth. And there’s nothing wrong with changing it up a little bit.

But by now, you’re so good at this, your body is so adapted, it’s very easy to go with one meal a day. However, if your weight is very stubborn or if your blood glucose or fasting insulin is just really stubborn and won’t budge, now what can break that plateau is to add some longer fasts. So if you are used to eating one meal a day, if you’ve got your body conditioned to that, then it’s very easy to just skip a whole day entirely. And by the time you wake up the next morning, you’ve probably gone at least 36 hours. And then if you make it to lunch, you have 42 hours. So doing these little bit longer fasts can typically break those plateaus and get you much deeper into that fat-burning zone.

So let’s say that you’ve done one or more 30-day periods with this, and now you have reached a good weight or good blood glucose or you reversed your type 2 diabetes or your cholesterol values. Then what? You start playing around with it. Now, for some people, they’re going to be fine eating one meal a day. Like I said, for myself, I have a hard time maintaining my ideal weight. I get too skinny. So I like to increase and eat two or three times a day in a six to eight-hour period. So this is going to be different for different people. Just play around with it and see what works for you.

And then from time to time, you watch this video again because every time you’re tempted to think of yourself and say, „I am the way I am,“ you scratch that thought and remind yourself that you are the way you recreate yourself moment to moment. Change is inevitable. Change is easy. If you’re going to change, then why not change it to something that you’d rather be?

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