You probably know some people that wake up ravenously hungry and swear how they would faint if they didn’t eat their breakfast first thing in the morning.

On the other hand, you’ve most likely met one of those people who just don’t seem to need much more than a cup of coffee before lunchtime.

You could even be amongst those who claim their stomach needs a few hours to “wake up” and can’t eat breakfast until they’ve been awake for a little while.

But, what is it that eating breakfast specifically does to your body?

Or rather, what is it that happens to our bodies when we skip the famous ‘most important meal of the day’?


Some nutritionists, like Sharon Collison, a clinical instructor in nutrition at the University of Delaware, noticed that those of their patients who struggled to lose weight tended not to take in enough calories during the morning, leading them to feel hungrier during the afternoon and overeat.

Although this is not information coming from a clinically controlled study, the experience of licensed dietitians like doctor Collison should not be discounted – they have experience in dealing with actual people and their daily nutritional habits and can pick up on patterns in a more sophisticated way that is feasible for some clinical studies!

That being said, there are actual studies that show this is true.

A study done in 2011 shows that caloric intake after 8.00 PM can lead to increased body weight and obesity.

It used novel methods to prove this and was fairly rigorous in meal tracking, requiring all participants to track their food intake and time through an app called MealLogger.


A study from 2017 published in The American Journal of Clinical Nutrition found that skipping breakfast increased inflammatory peripheral blood cell processes after lunchtime, compared to skipping dinner or not skipping any meals.

Both skipping breakfast and skipping dinner made the participants increase their metabolic energy consumption, but it was only skipping breakfast that had the unfortunate side-effect on an individual’s health.

Inflammation is the result of increased white blood cells trying to fight a viral or bacterial infection. However, these processes can sometimes be overly reactive, like with allergies, and can cause a big mess in your body.

Skipping breakfast might increase the irritability of your organism – so it could be more trouble than it’s worth if you’re the type of person to easily reach for decongestants or ibuprofen. This increase in inflammatory processes seems to be especially noticeable in obese people.

Another study from 2017 finds that chronic fasting, such as regularly skipping breakfast, can lead to metabolic inflexibility between switching from sugar to fat as a source of energy for the body, which can then lead to chronic inflammation.


If you’re the kind of person who works out first thing in the morning, skipping breakfast can ruin your workout.

This doesn’t just mean going to the gym, mind you – you could be a morning runner or somebody who walks to or bikes to work.

Not eating breakfast before a workout can make you feel dizzy, weak, and can lower your usual performance and can even lead you to pass out.

The Mayo Clinic recommends going into a workout well fueled. Make sure to eat at least an hour before your workout, and aim for something easily digestible, like foods high in carbohydrates and low in fiber.

They remind people to replenish themselves with a second meal after their workouts if these are particularly strenuous like running or swimming.


A small randomized control study published in the Journal of Physiology looked into the effects of 6 weeks of morning fasting, also known as skipping breakfast, in both obese and normal-weight individuals.

This study analyzed the participant’s fat burning and metabolic rates before and after the study.

It found that for normal-weight people skipping breakfast increased fat burning – probably by extending the fasting that started the night before, which was noted to be at least 10 hours for all individuals.

The process of burning fat for energy is known as ketosis and is famously used as the basis of the Keto diet.

Another form of fasting that is used not only for weight loss but also for weight management and better focus by many tech CEOs from Silicon Valley is intermittent fasting.

This nutritional lifestyle also focuses on pushing the body into periods of ketosis, increasing fat burning.


Insulin resistance is very much a disease of the modern age. It is very common in women and can lead to some other health problems like PCOS – polycystic ovarian syndrome or type 2 diabetes.

Morning fasting helps lower blood sugar levels by, simply, not introducing any new carbohydrates into your body for an extended period of time. A few hours after a meal, as it digests, your insulin levels spike.

People who have issues with insulin resistance cannot metabolize this insulin spike appropriately, so their body gets rid of the insulin by throwing your whole hormonal balance off.

Most forms of treatment for insulin resistance rely simply on mealtime management and strict diets, as well as trying to lower the number of times a day your insulin spikes and falls – and this is precisely where skipping breakfast can be your ally.

It should be noted that another study done in 2002 by Harvard found that skipping breakfast can actually increase your risk of type 2 diabetes, especially in older women, so take this into consideration if you belong to this cohort.


Most of the results are confined to animal studies, but there are more than a few of those that suggest that morning fasting boosts brain function and furthermore, it even prevents neurodegenerative disorders.

The second claim is reinforced by two studies from the PubMed Central database pertaining to Alzheimer’s disease and Parkinson’s disease.

This research is still in its nascent stages but is nonetheless encouraging. Studies done on mice found that fasting improves cognitive ability and preserves brain health.

Zach Iris of the Gingerhill Farm and Retreat Center rests his claims on the power of ketosis. He says that skipping breakfast can make you sharper and healthier because fat is a superior source of energy for both the brain and the body.

Neurosurgeon Dr. Rahul Janidal swears by skipping meals in his book “Neurofitness”.  Metabolic switching, the process of switching from using glucose to ketones that happens throughout the night and extends to the morning when skipping breakfast, helps awaken the mind, sharpens the senses and makes your brain more resistant to injury and disease.


Cortisol is the body’s main stress hormone. It is produced by the adrenal glands (the same little guys above your kidneys that produce adrenalin) and its overproduction can seriously hurt your kidneys.

When your body doesn’t have enough glucose stored to produce glycogen, vital for brain function, it can compensate by producing more cortisol.

Doctor Barry Sears, president of the non-profit Inflammation Research Foundation, says that this is what happens when you skip breakfast and that it should be prevented by eating a well-balanced breakfast that needs to include at least 25 grams of protein. Ideally, this kind of breakfast should also keep you satiated throughout the day, preventing hunger and fatigue.

In 2014 a study was done at the University of California, comparing the cortisol and chronic stress levels of both normal-weight and obese women, half of which skipped and half of which regularly ate breakfast.

It concluded that the cortisol levels of breakfast skipping women were much higher but the overall stress levels remained similar between the two groups of women.

Men’s cortisol levels are highest in the morning, after waking up – usually around 7 AM.

If you don’t eat something at that time to bring them back down, this could seriously affect both your day and your renal health, based on research done at The University of Texas in Austin and claims made by Doctor Josh Axe, nutrition specialist.


A study done on rats found that those subjected to occasional fasting had a lower rate of aging than the control group. They lived 83% longer as well.

Autophagy is a natural process that ‘removes cellular junk’ which occurs while we sleep and seems to be protracted by skipping breakfast.

Many more studies have been done on animals, ranging from roundworm to mammals that seem to agree – regular fasting can extend lifespan and decrease the risk of other age-related diseases.

Studies were done in 2014 on breakfast skipping in humans cite preexisting research confirming claims of anti-aging benefits of caloric restriction – which can be achieved through skipping breakfast.

One such, rather famous, study researched the causes of longevity amongst the people of Okinawa, a region in Japan.

This study credits their fasting practices and caloric restriction as one of the main causes of the health and longevity of this population.


Men specifically need to be mindful of skipping breakfast, since a study from Harvard University tied morning fasting to a 27% greater risk of heart attack and cardiovascular disease.

The misbalance of hormones created to regulate blood sugar in the absence of breakfast is the likely culprit, causing obesity and plaque buildup in the arteries and can cause heart problems.

Another US conducted the study  from a large sample of people who were all around 50 years old found that those who regularly skipped breakfast had an 87% greater risk of dying from cardiovascular causes.

However, another set of studies showed that skipping breakfast can affect cardiovascular health positively, although indirectly.

This is achieved through the positive effects of morning fasting on blood pressure, cholesterol levels, and triglycerides.

An additional study with a slightly larger sample found that skipping breakfast lowers the risk of coronary artery disease.

These conclusions differ because the types of studies (some were following cohorts and noting causes of death while others were doing questionnaires) and the time they were conducted do.

The smaller, newer studies are the ones giving more promising results (they are also the ones using subjects of various ages rather than just those around 50 years old).


Some kinds of vital intestinal bacteria only grow when we are fasting.

During this time, the mucus level in your digestive tract increases and bacteria use this to feed and multiply. Microbiologist Kiran Krishnan recommends skipping breakfast as a part of an intermittent fasting diet for this very reason.

Our gut microbes have developed alongside us for hundreds of years, meaning that they need to follow our metabolic circadian rhythm.

Humans didn’t use to have regular meals for most of history, so the gut microbiome relies on long periods where no food was consumed to replenish itself.


Young women need to pay attention when skipping meals too frequently because a lowered daily caloric intake can lead to skipped or irregular menstrual cycles, research finds.

Another study conducted in 2009 looked at college-aged women who skipped breakfast and found that their periods were less regular and more painful.


Nobody likes morning breath. Imagine having your morning breath mixed with coffee breath, and nothing to keep it at bay.

The absence of breakfast means that there is nothing there to remove your bad breath and neutralize the odor.

Eating breakfast helps produce saliva that removes bacteria from your tongue – bacteria is what causes the bad smell in the first place, a US Health and News report claims.


Different people like different kinds of breakfast – some go for a protein-rich option, like eggs, some like it hardy with lots of fats like avocados and bacon, others stick with fruit and yogurt, and some tend to eat a sweet breakfast – cereal and pancakes, anyone?

If you decide to skip breakfast, a food group you usually consume during that time can be left out of your day and in the long run have lasting effects on your health.

An overload of sugar is not good for you at any point during the day so if you’re the type to over-indulge during breakfast, skip away.

If you are, however, a practitioner of a breakfast high in fiber and protein that usually keeps you satiated throughout most of the day, you might need to reconsider.

Some diets and cultures lead people to consume certain kinds of foods only during breakfast – one such diet is the famous United Nations diet which relies on a daily breakfast of fruit for the duration of the diet.

Some women tend to keep this regimen after they finish with their weight loss – the diet itself even encourages it.

Combine most of your vitamins and fiber coming from your breakfast with skipping the said meal and hear the scurvy and various other avitaminosis knocking!


You may have heard the word hangry before. You’ve probably been hangry yourself at some point.

The word is a portmanteau of hungry and angry and describes the state of irritability and irrationality that can be brought on by hunger that the individual is unaware of.

If you’re skipping breakfast but are actually hungry, you can start your day grumpy – this is not great news for you or your coworkers.

A study done in the United Kingdom found that participants experienced worse moods and were less calm before in the first half of the experiment.

Their mood improved in the second half after they were allowed to consume the first meal of their day.

Another side-effect of hangriness is that once you realize you have it, you might feel a sense of urgency to take care of it.

This can lead to unhealthy cravings and overindulgence in certain foods.


As you can see, not all of the effects of skipping breakfast are positive – it really depends on your personal lifestyle, overall health, and fitness level.

Your reasons for skipping breakfast play into this as well – if you’re doing it on purpose as a way to decrease calorie intake or as part of a fasting diet, and if you stick to it – then you’ll probably avoid some of the negative effects and reap the positive.

If you’re skipping breakfast due to poor planning or a strange mealtime schedule like night snacks or night shifts, then you’re more likely to suffer the negative consequences.

The studies themselves tend to come to seemingly contradicting conclusions, but that depends on the study size, what and when was measured as well as who funded the study (studies funded by the food industries tend to find eating breakfast more favorably).

All in all, listen to your body, know your medical history, and hey – skip breakfast every day if that’s what works for you!

14 Things That Happen to Your Body When You Skip Breakfast

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