Is Breakfast Still the Most Important Meal of the Day?

“Breaking-fast,” or breakfast, has been endorsed as the most important meal of the day. Replenishing energy stores from overnight fasting boosts energy levels and cognitive function and helps control weight by minimizing fluctuations in blood glucose and preventing binge eating later in the day. But is this still the case today? Has the evolution in the convenience and accessibility of foods, in particular ultra-processed foods and refined high-carbohydrate breakfast items, changed this dogma? Well, the answer is, it depends.

Intermittent fasting, in particular time-restricted feeding, where anywhere from a 6 to 10-hour eating window is followed by fasting, has been growing in popularity as this is the least restrictive form and has less side effects of irritability, and headaches, and decreased concentration (aka “hangry”). Say, for instance, you only consume food from 12 pm to 8 pm and fast the rest of the day. You are essentially skipping breakfast. Short-term studies have found benefits in bodyweight reduction and improved cardiometabolic health.

However, in contrast, our inherent circadian rhythm favors breakfast. Consuming most of our meals during the active phase or light phase of the day results in peak gastrointestinal emptying/motility, increased insulin sensitivity, and lower appetite (in part due to low levels of the hormone ghrelin, which increases appetite). In theory, if we were all able to use our circadian rhythm to our advantage but also eat during a time-restrictive window (6am-4 pm), we could take advantage of all the pleiotropic benefits of fasting. But for most of us, this isn’t realistic because we are social beings and interact with our community that very much revolves around dinner gatherings with family and friends.

So, what’s the solution? Here are a few tips for using everyday that consider the above:

As a reminder to myself and my patients:

Changing dietary habits is a gradual process with delayed gratification. One small change a day will make all the difference in your lifetime.

Eat well and be well,


  1. Time-Restricted Eating: Benefits, Mechanisms, and Challenges in Translation – PMC (
  2. Nutrition and the Circadian System – PMC (
  3. Effects of Intermittent Fasting on Health, Aging, and Disease | NEJM

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