Why Is Breakfast So Important?

Why Is Breakfast So Important?

Is breakfast really the most important meal of the day? Why exactly is breakfast so important? In a nutshell, eating breakfast regularly reduces risk of type 2 diabetes, cardiovascular disease (improves heart health!) and all-cause mortality (a general indicator of health and longevity), no matter what you eat for your first meal of the day!

But, what exactly is the importance of breakfast specifically?

Breakfast is an important regulator of our circadian rhythm (how our body knows whether it’s day or night) and of our hypothalamic-pituitary-adrenal axis (which controls reactions to stress, like fight or flight). The circadian rhythm and stress axis are linked via the hormone cortisol, which is known as the master stress hormone but is also one of the main circadian rhythm hormones, with the other being melatonin. Cortisol has a natural ebb and flow throughout the day. It peaks a couple of hours before waking up. It’s part of the wakening response, part of how we have energy in the morning, and then it gradually decreases throughout the day, with little spikes after each meal, after exercise, and after stress.  Melatonin does the opposite, peaking a couple of hours before going to bed, helping to initiate the sleep response and then slowly decreasing until morning, ideally staying pretty low all day.  A 2002 study showed that people who skip breakfast have higher morning cortisol levels that fall off more slowly than people who always eat breakfast, which increases the amount of cortisol in the system, which in turn causes stress. People who skip breakfast also have higher spikes of cortisol after lunch. That means we have a healthier stress response and better-regulated cortisol levels when we routinely eat breakfast. Cortisol impacts insulin sensitivity, digestion efficacy, appetite and cravings, immune function, cardiovascular function, and kidney function. For example, eating breakfast can improve insulin and blood sugar level response to subsequent meals the rest of the day, in addition to influencing food choices, and how much food we eat later in the day, generally making us crave less energy-dense foods and making it easier to choose foods like fresh fruits and veggies. Not only do breakfast eaters regularly have better regulated morning cortisol, they also have lower perceived stress.  In fact, a 2016 study found that chronic stress was associated both with breakfast skipping and poor diet quality and a 2015 study showed showed that women who regularly skipped breakfast had disrupted cortisol rhythm, hypothalamic-pituitary-adrenal axis overactivation, and elevated blood pressure, even though they had the same levels of perceived stress as the women who always eat breakfast. Breakfast is a zeitgeber (anything that influences our body’s clock). We have all kinds of biological processes that we prioritize when we are awake or asleep and having a cemented circadian rhythm improves energy levels during the day and sleep quality at night. The most important zeitgeber is light. Others include temperature fluctuations between day and night, social interactions, exercise and meal timing.

Check out my video where I talk about why eating breakfast improves overall health.

And, if you want to know even more about breakfast check out my Science Stroll – “Is Breakfast the Most Important Meal of the Day?“. Here you can find out my thoughts on all things related to breakfast including optimal timing for breakfast, and breakfast ideas for people who aren’t hungry. I also explain that it’s more important that you eat breakfast than what you eat. Ideally we we would have a balanced breakfast complete with healthy fats, protein, and high-fiber, but if cereal is what you like for breakfast, that’s great too. You could always make it a more complete and balanced breakfast by adding some Greek yogurt or cottage cheese for protein, or adding some fresh fruit like blueberries. However, given the studies that routinely show that eating breakfast is linked with numerous health benefits, eating breakfast cereal is vastly superior to skipping breakfast altogether. And if you want to know my thoughts on intermittent fasting check out my FAQ post – “Breakfast or Intermittent Fasting?“.

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