The debate around intermittent fasting in the morning – rather than eating breakfast – has gained attention in recent years. Health professionals and enthusiasts often find themselves on opposite sides of the discussion, which can make personal decisions in the matter more challenging. Before deciding which option is best for you, it’s important to consider the arguments for both practices and examine the benefits, potential drawbacks, and the science behind each approach – which is what this blog is here to help you do.

Fasting vs. Breakfasting

METABOLISM

The word metabolism refers to the rate at which your body burns calories or uses energy. Many of our in-home and virtual personal training clients seek advice on how to improve their metabolism, which can be (modestly) achieved through building muscle mass. “Some people claim that eating breakfast “kick-starts” the metabolism, but this is a myth. These people are referring to the thermic effect of food, which is the increase in calories burned that occurs after you eat” (Healthline, 2017), aka digestion.

While there are a few factors within your control that affect your metabolism – like the average amount of food you eat within a 24-hour period, your lean muscle mass, and your activity levels – metabolism speed is largely determined by your genes, and whether you eat breakfast or not will have little to no real effect. That said, time-restricted “feeding schedules have favourable metabolic effects by intermittently inducing the metabolism of fatty acids to ketones” (National Library of Medicine, 2022), which are acids your body creates while using fat stores (rather than glucose) for energy. This can benefit fat-loss over time.

COGNITIVE FUNCTION

Eating a protein-rich breakfast has been linked to better cognitive function, particularly in children and adolescents. Studies suggest that a nutritious breakfast can enhance memory, concentration, and overall mental performance. This is an important factor to consider if your mornings require a significant amount of focus or concentration: a balanced breakfast can fuel your brain through morning classes or study. Though intermittent fasting is also thought to improve mental clarity, there is no significant evidence of a positive cognitive effect at this time.

NUTRITION

A balanced breakfast can contribute significantly to your daily intake of essential nutrients. Many breakfast foods – such as fruits, whole grains, eggs, and dairy products – provide vitamins, minerals, and fibre that are vital for good health. Many of our in-home personal training clients in Toronto struggle to reach daily nutrition targets, so consuming a healthy meal first thing in the morning (even if it’s small) can make a big difference.

WEIGHT

There is some evidence to suggest that eating breakfast can aid in weight management. Regular breakfast-eaters tend to have healthier body weights, which could be due to better appetite control and reduced likelihood of overeating later in the day. However, this link is largely attributed to breakfast-eaters having healthier lifestyle habits in general rather than the morning meal itself.

Intermittent fasting is thought to aid in weight loss by limiting the eating window. On top of the possible production of ketones, fasting can reduce your overall caloric intake, which contributes to weight-loss. This only works if your hunger levels post-fast do not create the urge to over-eat or consume less nutritious foods, which is the case for some.

INSULIN

“A few small studies have shown that intermittent fasting can have health benefits for people with diabetes” (Very Well Health, 2024), as fasting can improve insulin sensitivity, which is crucial for preventing and managing type 2 diabetes. Better insulin sensitivity means that the body can use glucose more effectively, reducing blood sugar levels.

EFFICIENCY

Lastly, fasting simplifies your routine by reducing the number of meals you prepare and consume. This can lead to a more mindful and intentional approach to eating while saving time.

FINAL WORDS

Bottom line: the decision between eating breakfast or fasting is highly personal. Consider the following factors: Are you aiming for weight loss, improved cognitive function, or better metabolic health? Does your daily routine allow for regular breakfast, or is a fasting window more practical? Pay attention to how your body responds to each approach. Some people thrive on a hearty breakfast, while others feel more energized skipping it. What matters most is finding an approach that aligns with your health goals, lifestyle, and preferences.

If you’re looking for more personalized advice, Nielsen Fitness offers nutritional support with our in-home and virtual personal training packages. Book a free first workout here to start achieving your health goals, today!