Skipping Breakfast? Here’s What Happens When You Skip Breakfast


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One of the more common questions that people ask in terms of scheduling their dietary habits is: “Is it bad to skip breakfast?”

A similar question that many dieters wonder is, “Should I skip breakfast to lose weight?”

After all, morning fasting is a popular way to support weight loss and is a common feature of intermittent fasting diets.

However, almost everyone has heard the pervasive theory that “Breakfast is the most important meal of the day,” so where does the truth lie? What happens if you don’t eat breakfast?

In this article, we will discuss what happens if you don’t eat breakfast, including the various pros and cons of skipping breakfast and doing morning fasting instead.

We will cover: 

  • Is It Bad to Skip Breakfast? 
  • What Happens If You Don’t Eat Breakfast?
  • Should I Skip Breakfast to Lose Weight?
  • Is Skipping Breakfast Bad for Health?

Let’s get started!

A plate with food from 10 -6, showing intermittent fasting and skipping breakfast.

Is It Bad to Skip Breakfast?

The prevailing advice stating that breakfast is the most important meal of the day certainly makes it sound like skipping breakfast is bad.

However, surveys suggest that up to 25% of Americans regularly skip breakfast, and morning fasting is also practiced by a sizable percentage of the population in many other countries and cultures as well.

Much of the reasoning behind the dietary advice to eat breakfast stems from studies that suggest that people who regularly eat breakfast tend to be healthier.

For example, evidence has demonstrated that breakfast eaters are less likely to be overweight or obese and tend to have a lower risk of several chronic diseases.

However, it’s important to note that these studies only demonstrate correlations, not causations.

Pached eggs and salad.

In other words, these are observational studies that suggest that people who eat breakfast regularly are more likely to be of normal weight and healthier, but there isn’t sufficient evidence to say that the health benefits were caused exclusively by eating breakfast.

Because the current nutritional guidelines suggest that people should eat breakfast to promote optimal health and weight management, it’s reasonable to assume that breakfast eaters may be more likely to follow other nutritional and health advice as well, which could contribute to their overall improved health status.

Indeed, studies suggest that people who eat breakfast typically have a healthier general diet that is higher in fiber, fruits, vegetables, and micronutrients, than people who habitually skip breakfast.

Similarly, some studies have found that people who do not eat breakfast on a consistent basis also tend to have certain other unhealthy habits, such as drinking alcohol, smoking cigarettes, and being less physically active.

There are few, if any, well-controlled, randomized scientific studies that really demonstrate that eating breakfast directly lowers your body weight and decreases your risk of lifestyle diseases.

A bowl of yogurt and fruit, juice and coffee.

What Happens If You Don’t Eat Breakfast?

One of the prevailing assumptions is that eating breakfast kick-starts your metabolism and helps you burn more calories throughout the day. However, studies suggest that this is more of a myth than reality because it seems that the number of calories burned over 24 hours is the same whether or not people eat breakfast or skip breakfast. 

The body’s metabolic rate does not seem to jump up and burn through a bunch of extra calories just because you start eating earlier in the day. 

As long as the same number of calories are consumed over the 24-hour period, there seems to be little difference in how your metabolism responds overall to eating or skipping breakfast.

Should I Skip Breakfast to Lose Weight?

People who are trying to lose weight often ask, “Should I skip breakfast to lose weight?”

In many ways, the question makes sense. If you skip a meal altogether and do not compensate by eating additional calories later on in the day, skipping breakfast can help you generate a caloric deficit, which is necessary to lose weight.

A large breakfast of eggs, toast, sausage beans, and veggies.

For example, if you were previously following a 2000 calories/day diet with three meals and two snacks, and drop your 500-calorie breakfast, you will now only be eating 1500 calories per day.

Over a week (or 7-day period), this will result in a net reduction of 3500 calories, which is the caloric deficit necessary to lose a pound of body fat.

Indeed, some studies suggest that skipping breakfast is not a good solution for weight loss.

At the same time, with evidence suggesting that people who eat breakfast are less likely to be overweight or obese, it can become confusing to determine whether skipping breakfast will help you lose weight or will cause you to gain weight.

Again, there is a lack of conclusive evidence here to point to either answer.

In many cases, the result of skipping breakfast on weight loss is individualized. 

Some people find that skipping breakfast leads to increased hunger later on in the day that exceeds what would have been experienced had they eaten a moderate number of calories at breakfast. 

A large breakfast of fruit, crossaints and bread.

In other words, the compensatory appetite spike from skipping breakfast is significant enough that they have to consume more calories to quell their hunger than they would have had they eaten a normal breakfast.

In the example of our fictitious subject who skips their 500-calorie breakfast, they might end up feeling starving by mid-morning, indulging in an extra snack, and eating an even bigger lunch because they never seem to be able to get ahead of their hunger and reign in their appetite to normal levels. 

As a result, by the end of the day, they might have consumed 800 additional calories, bringing the total daily caloric intake to 2300 calories (2000 baseline – 500 for the skipped breakfast + 800 from compensatory overeating).

In these types of scenarios where dieters do experience a big spike in appetite, skipping breakfast can cause weight gain because you are ultimately eating more calories per day.

However, compensatory spikes in appetite and subsequent consumption of calories are not necessarily experienced by everyone who skips breakfast.

A plate of breakfast including eggs, ham, tomatoes and bread.

In fact, some studies have even found that skipping breakfast may decrease overall daily calorie intake by up to 400 calories, which again is primarily due to the fact that if you don’t eat breakfast, you are removing an entire meal—and the resultant calories— from your daily caloric intake.

A recent randomized controlled trial investigated the effects of eating breakfast or skipping breakfast on weight loss in 309 adult men and women who were overweight or obese over the course of 16 weeks.

At the end of the 4-month study period, there were no significant differences in the amount of weight lost between breakfast eaters and subjects who were told to skip breakfast. 

Moreover, compliance in both groups was around 94%, so subjects indeed followed the instructions, allowing us to trust the results.

Similar studies have also found breakfast habits do not seem to affect weight loss results in one way or the other.

A large breakfast of eggs, toast, bacon, salad, and avocado.

Is Skipping Breakfast Bad for Health?

Conventional advice suggests that if breakfast is “the most important“ meal of the day, skipping breakfast will be deleterious to your health. However, morning fasting is a component of an intermittent fasting diet in which dieters extend the overnight fast and delay the first meal until later in the day. 

For example, with 18/6 intermittent fasting, there is an 18-hour fast per day and just a 6-hour eating window. 

This might look like fasting all the way until noon time, consuming your first meal at that point, and then finishing all eating by 6 PM. You then fast again until noon the following day and repeat this time-restricted eating pattern daily.

Studies have demonstrated a variety of health benefits of intermittent fasting, including a reduction in total caloric intake, fat loss and improvements in body composition, better blood sugar regulation and insulin sensitivity, and reduced inflammation and oxidative stress, among other benefits.

A person eating breakfast.

With that said, not everyone feels well by skipping breakfast or practicing an intermittent fasting diet. 

In fact, some people experience hypoglycemia (low blood sugar), headaches, lightheadedness, difficulty concentrating, and, as previously discussed, resultant surges in extreme appetite that lead to eating a higher number of calories and gaining more weight.

Ultimately, what happens when you skip breakfast is somewhat individualized to your own body, lifestyle, and overall diet

You may find that you feel more energized and do not experience rebound hunger if you don’t eat breakfast, whereas you might experience distracting hunger pains, low energy, difficulty concentrating, and a feeling of constantly needing to “catch up“ by eating more food the rest of the day. 

Experiment and see what works well for you. If you are going to eat breakfast, remember to consume nutritious, satiating foods that are high in protein, fiber, and micronutrients. Stay away from refined grains, baked goods, and sugary cereals.

For some high-protein breakfast ideas to fuel your day, check out our recipes here!

A person eating breakfast.
Photo of author
Amber Sayer is a Fitness, Nutrition, and Wellness Writer and Editor, as well as a NASM-Certified Nutrition Coach and UESCA-certified running, endurance nutrition, and triathlon coach. She holds two Masters Degrees—one in Exercise Science and one in Prosthetics and Orthotics. As a Certified Personal Trainer and running coach for 12 years, Amber enjoys staying active and helping others do so as well. In her free time, she likes running, cycling, cooking, and tackling any type of puzzle.

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