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One of the lesser understood but clinically useful nutrition strategies when it comes to weight, energy, mood and appetite regulation is the little known field of bio-circadian nutrition. Simply put, when we eat is often as important as what we eat. Like all aspects of nutrition science, there’s a very elegant continuum of possibilities that exists from person to person. In other words, we’re all nutritionally different, so the only true hard and fast rules are the ones that apply to your unique nutritional experience. I’d love to share with you some clinical, real world observations, along with some of the simple science behind eating rhythm. See if any of this might apply to you.

Let’s say that you wake up in the morning and decide not to eat breakfast. You figure “Well, I’m not hungry, I’ll just have some coffee, maybe a little bit of cereal or muffin or bagel. If I eat this meager amount of food until lunch I’ll be a good girl and lose weight.” But this really isn’t such a good strategy after all.

That’s because body temperature is naturally rising in the morning to prepare you for a metabolic resurgence.

In the absence of food, or in the absence of enough food, the body gets concerned. It says something like: “Hey, I thought I was preparing to raise metabolism with a morning meal. I thought my food source was abundant and dependable. There’s nothing here. I must be shipwrecked on a desert island. Or maybe there’s a famine. Better slow down metabolism, store fat and don’t build any muscle because there are lean times ahead.”

This genetically programmed survival response is a brilliant mechanism for supporting the continuation of life in times of emergency. When the brain senses trouble with the food supply, it does the most simple and impacting metabolic reprogramming to conserve energy – store fat and forget about building muscle. Just the opposite of what you’re trying to do by denying yourself food for weight loss.

To make matters worse for weight loss, many people have a breakfast that consists of one ingredient: coffee. Coffee by itself raises cortisol levels. The coffee lobby doesn’t want you to know this (I used to work for them) because this basically means that coffee can chemically mimic the stress response and cause abdominal weight gain. This doesn’t mean coffee is bad. I love coffee. It just means that when you combine lack of food (survival response – elevated cortisol), anxiety (stress response – elevated cortisol), and caffeine (mimics stress response – elevated cortisol), you have three factors that powerfully synergize to send cortisol production through the roof, suppressing digestive metabolism and depositing weight.

Again and again, we see the importance of cortisol levels in health and weight.

Cortisol isn’t a bad chemical. Its an integral component of an alive human body. Without it we couldn’t exist. In the right quantity it helps maintain the proper functioning of every major system in the body. When we overproduce cortisol, though, we age prematurely, wear down our weakest links, and gain weight around the middle.

Strangely enough, the chemicals that wreak the most havoc in our lives and prove to be the most toxic are often the ones we self-produce. That’s why the biggest pharmaceutical companies in the world are busy behind the scenes perfecting home test kits so you can measure your own cortisol levels. Of course, if you find that your cortisol level is too high, you can buy whatever drug they concoct to lower it. But you needn’t wait for the next magic bullet to improve metabolism and lower your weight. No drug has ever worked for this purpose and none of them ever will. Just follow the inborn rhythms of the body and you’ll liberate yourself while putting the diet – pill pushers out of business forever.

Now, lets imagine it’s lunchtime. You’ve had your small or nonexistent breakfast and perhaps a second cup of coffee in the mid-morning. You have some energy and you don’t feel the need or the desire for a big lunch. Maybe you think you’re being good by holding back on the calories; perhaps you don’t have much time for lunch anyway, so why not grab half a sandwich, or a salad with a no-oil dressing, or have a late lunch at two or three o’clock?

If this is your strategy, what seems to be sensible is actually working against you. First, the body is designed to optimally digest and calorie burn when the sun is at its apex in the sky. This is a little known but fascinating scientific fact. By not putting fuel in the furnace at this time, or simply by not eating enough, you miss your peak metabolic window of opportunity, which is approximately 12:00 to 1:30 in the afternoon. Missing this opportunity is the equivalent of being all dressed up with no place to go. Chances are you’ll be ravenous by three or four o’clock, maybe head-achy or irritable, and grab an unhealthy snack. In other words, you’ll be suffering from arrhythmia – being out of sync with your natural circadian flow.

And by eating a tiny breakfast and minimal or late lunch, you assure major hunger in the late evening. Many people who follow this arrhythmic sequence of events find that they have a substantial snack before dinner because they’re so hungry they cant wait for their actual meal, or they’re simply ravenous in the later evening hours and eat a huge dinner. Unfortunately, our thermic efficiency – meaning our ability to burn calories – is lower in the evening. So the exact same large meal eaten at 8pm actually places more of a caloric load on the body than if you ate it at lunch. Probability wise, it’ll make you fatter.

One of the downsides of consuming a high volume of food before bed is that we miss some of the great metabolic gifts of sleep.

As you slumber at night the body shifts the bulk of its metabolic focus to maintenance, detoxification, repair, and growth of its tissues and organs. When you grow new muscle and bone, you do so as you sleep. The liver, which is our primary organ of detoxification, does the bulk of its work in the late evening and early morning hours. Sleep is not the most publicized of our metabolic activators, nor is it the sexiest, but if this rhythm isn’t fully honored we pay the price.

By consuming a big meal right before bed, much of the metabolic energy that is usually spent on maintenance, detoxification, repair, and growth is necessarily rerouted into digestion. That’s simply how the body works. Short-term survival needs take precedence over long-term ones. So with an excess of blood flow and metabolism focused on processing your meal as you sleep, you’ll most likely wake up feeling congested and heavy because you didn’t detoxify fully during the night. The period between dinner and breakfast is evolutions built in fast. That’s because the fasting state is the ideal biological milieu to rebuild the body. And that’s also why breakfast is called “break-fast” – we’re ending this necessary period with food in the morning.

So if you wake up feeling tired and toxic from eating a large, late dinner because you didn’t have real relaxed meals during the day, you’ll naturally repeat this arrhythmic pattern. You wont be hungry in the morning because your body will still be in detoxification mode when instead it should be readying itself for the metabolically stimulating activity of eating. Lunch will then feel to your body like breakfast, and dinner will be interpreted by your body as lunch-time for the biggest meal. Some time after the dinner that your body thought was lunch, you’ll be looking for “dinner” and end up having a late-night snack.

Oftentimes you’ll hear nutritionists recommend that you eat your evening meal about four hours before bedtime. A four-hour time period is sufficient for most people to metabolize a meal. You will then go to bed without raising your body temperature; through the metabolic effect of food, thus increasing your probability of restful sleep. You’ll also do what you were meant to do while laying in bed – healing, detoxifying, rebuilding, and so fourth-without sidetracking vital metabolic force into digestion.

To accomplish this, you may need to retrain your body and reorient your lifestyle. Focus on having a smaller and earlier dinner and have a more robust breakfast. Eating a relaxed, sane, sensuous lunch makes it easier to have a lighter dinner.

These are but a few of the nutritional tricks you can experiment with to see if they work for you, your body, your weight, and your style of living. Experiment. Be curious. Be a scientist of your own body. Be willing to make a few mistakes, and have a few successes. And of course, I’d love to hear your thoughts and insights about the dance of nutrition and rhythm in your own professional practice or personal experience.

My warmest regards,
Marc David
Founder of the Institute for the Psychology of Eating
© Institute For The Psychology of Eating, All Rights Reserved, 2014


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  • Michele

    Hi Marc, I just recently started to eat my last meal at around 6:00 pm. And for the past three nights I’ve been having very vivid dreams. I think that previously eating so late had blocked my ability to deeply dream, because, as you mentioned all the other functions of the body get sidetracked by digestion. I have been waking up energized and more serene. The information that you write is invaluable and thank you for making it so easy to understand!

    • Hi Michele,
      It’s wonderful to hear that you are waking more energized and prepared for your day! Its amazing what following your bodies natural pattern can do for your overall well-being. Pay attention to what those dreams are telling you…
      Warm Regards,

  • Sarah

    I was wondering if you can direct me to the science that indicates this: “the body is designed to optimally digest and calorie burn when the sun is at its apex in the sky. This is a little known but fascinating scientific fact.” I’ve been curious about this and would appreciate more information. Thanks!

    • KarnaN

      Hi Sarah, Marc found this in Guy Murchie’s book, “The Seven Mysteries of Life”. I hope this resource will be helpful for you.
      Karna Nau
      Director of Student Relations
      Like us on Facebook:

  • Michelle

    Marc, thanks so much for your wonderful writing and insight. I so much enjoy reading the blog. In thinking about timing and the body’s natural rhythms and processes, I’m wondering if exercising after eating slows or disturbs the digestive process. Should the four-hour window that it takes to metabolize a meal also be honored when it comes to exercise?

    Many thanks,

    • Great question! As always, how fast or slow we metabolize a meal depends on the individual. However, intense exercising directly after a meal will always disrupt the digestive process as you will move from the parasympathetic nervous system (optimal state of relaxation and digestion) to the sympathetic nervous system (a state of stress and high activity.) As a general rule you would want to wait about an hour or two after eating a big meal to ensure that you are properly digesting and assimilating your meal. A leisurely walk or light exercise on the other had has been said to enhance digestion, it’s more high intensity exercise that will have a negative effect on how well you digest your food. I hope this helps !


  • Marc — I have to say that since I’ve been giving myself the “sensuous lunch” my life is so much happier and calmer. This is a practice that I encourage my clients to try — with great success. The pace of the work week can make it hard to slow down — i teach them to give permission to themselves and then to others by saying, “I have to eat slowly, my health depends on it!”

    • Hi Amy K,

      How wonderful that you’ve made slowing down and nourishing yourself a priority. Thank you, as well, for sharing the word with your own clients. Isn’t it interesting that when we give ourselves permission to enjoy life, we actually do?

      Warm Regards,

      Marc David

  • Anjanette

    What if you were underweight and needed to gain? Should you still forgo eating a light snack before bedtime? Could this hinder or help the weight gain process for the individual?

    • Hi Anjanette –

      Good Question. I am sorry, but I cannot give a simple answer as this is a highly individual question and I’d need to ask you about 100 questions before I could give a useful answer. When trying to gain, we need to consume the right foods however we can, and perhaps whenever we can.

      Best regards
      Marc David

  • Sandra Chikhani

    I have changed my breakfast and lunch habits increasing healthy fats and quantities and feel excellent!!!
    I’m telling everyone I can about this…it’s truly positive. I now feel complete and whole!

    • Hi Sandra,
      Nice to see you here!
      So good to hear you’ve found something that makes you feel wonderful…


  • Jennie

    Hi Marc David, I am responding because I follow a diet which goes against everything you outlined in this article. While I grew up agreeeing with the principles you outlined, I was astonished at this new research. I still believe that you should not eat too close to bed so that your body will detoxify and cleanse/repair while you sleep instead of digesting food etc. However, as far as eating breakfast, I instead have coffee in the morning with MCT oil and coconut milk and some stevia. Cortisol is raised in the morning and is very important for fat burning and as long as you don’t introduce carbs in the morning, you can prolong the fat burning. The fat will keep you satiated until your first meal. I don’t eat that until about 11 am. The MCT oil also stokes the metabolism and getst he digestive system running, and a few hours after I have that I have a juiced lemon in about 24 oz water. I am not sure if you have ever heard of John Kiefer, he is a physicist who invented carb backloading and carb nite, and I follow an ultra low carb/ketogenic diet called the carb nite solution and I wonder if you have heard of this, and if not, it may be something you want to look into….I’d be curious what your thoughts are. thanks! Jennie

    • Hi Jennie,
      Thanks for your perspective here. I appreciate you’ve found something that works for you, but not everyone does well with a ketogenic diet, and someone who is in adrenal fatigue would hardly do well with an increase in cortisol in the morning. The point of this article was to get people thinking and experimenting with their diet rhythm in new ways that work for their body. There is always new science coming out and much of it is contradictory. The best thing we can do is find the thing that aligns with our own personal body wisdom.

      Again, thanks for sharing.

  • Deborah Rabjohns

    Hi Marc, Since following a ketogenic diet for the past four months my blood chemistries are worse.I was told to eat more fat and protein for anxiety and depression but fasting insulin, glucose and cortisol levels are worse also liver enzymes. Back to ???

    • Hi Deborah,

      Thank you for reaching out. I’m sorry, but I can’t answer your question. Every person is biochemically unique, and in order to truly figure out what would work best for you, I would need to ask hundreds of questions to even start scratching the surface. I would recommend you find a good holistic practitioner in your area to try to help get to the root of your problem.

      Good luck!


  • mary

    This is interesting but what happens when you work the midnight shift. When are you supposed to eat

  • Hi Mary! So glad to hear that you found this interesting! Yes, for many people who work midnight shifts, eating late at night is unavoidable. You get to set up a new rhythm to your eating that works for you. No matter what time you have to eat, just remember to bring in love and pleasure, which are also a huge part of digesting any meal. If you are curious to delve deeper and want to work with a coach we suggest checking out our Graduate Directory to find someone to support you in finding a rhythm of eating that works for you. You can check out our directory here:
    Good luck on your journey and if we can ever help you with anything else reach out to us anytime! Warmly, IPE Staff

  • Lisa

    I enjoyed this article and found it to have some good information. However, there is a great deal of research showing that a larger fast (by not eating breakfast) can be amazingly beneficial to the body and can really facilitate maintaining a health weight. Dr. Mercola has written a great deal about this approach. It’s fascinating. I like how early on in the article you mention we are all different…..because that is key. Not only are we all different, but our own needs shift and change. I think it’s okay to write about different approaches as long as we mention that important caveat.

About The Author
Marc David

Marc David is the Founder of the Institute for the Psychology of Eating, a leading visionary, teacher and consultant in Nutritional Psychology, and the author of the classic and best-selling works Nourishing Wisdom and The Slow Down Diet. His work has been featured on CNN, NBC and numerous media outlets. His books have been translated into over 10 languages, and his approach appeals to a wide audience of eaters who are looking for fresh, inspiring and innovative messages about food, body and soul. He lectures internationally, and has held senior consulting positions at Canyon Ranch Resorts, the Kripalu Center for Yoga and Health, the Johnson & Johnson Corporation, and the Disney Company. Marc is also the co-founder of the Institute for Conscious Sexuality and Relationship.