What Size Breakfast Is Best, By Science?

“Breakfast is the most important meal of the day”, the popular wisdom goes. But, what should it consist of, and how much should we be eating for breakfast?

It has been previously established that it is good if breakfast is the largest meal of the day:

Mythbusting Breakfast-Time

…with meals getting progressively smaller thereafter.

Of course, very many people do the inverse: small (or skipped) breakfast, moderate lunch, larger dinner. This, however, is probably more a result of when eating fits around the modern industrialized workday (and thus gets normalized), rather than actual health considerations.

So, what’s the latest science?

A plucky band of researchers led by Dr. Karla-Alejandra Pérez-Vega investigated the importance of breakfast in the context of heart health. This research was done as part of a larger study into the effects of the Mediterranean Diet on cardiovascular health, so if anyone wants a quick recap before we carry on, then:

The Mediterranean Diet: What Is It Good For? ← the answer, by the way, is “pretty much everything”

…and there are also different versions that each use the Mediterranean Diet as the core, while focussing extra on a different area of health, including one to make it extra heart-healthy:

Four Ways To Upgrade The Mediterranean ← most anti-inflammatory / gut-healthiest / heart-healthiest / brain-healthiest

What they found

In their sample population (n=383) of Spanish adults aged 55–75 with pre-diagnosed metabolic syndrome who, as part of the intervention of this 36-month interventional study, had now for the past 36 months been on a Mediterranean diet but without specific guidance on portion sizes:

• Participants with insufficient breakfast energy intake had the highest adiposity (which is a measure of body fat expressed as a percentage of total mass)
• Participants with low or high (but not moderate) breakfast energy intake had the larger BMI and waist circumference over time
• Participants with low or high (but not moderate) breakfast energy intake had higher triglyceride and lower HDL (good) cholesterol levels
• Participants who consumed 20–30% of their daily calories at breakfast enjoyed the greatest improvements in lipid profiles, with lower triglycerides and higher HDL (good) cholesterol levels
• Participants with lower breakfast quality (lower adherence to Mediterranean Diet) had higher blood pressure levels
• Participants with lower breakfast quality (lower adherence to Mediterranean Diet) had higher blood sugar levels
• Participants with lower breakfast quality (lower adherence to Mediterranean Diet) had lower estimated glomerular filtration rate (which is an indicator of kidney function)
• Participants with higher breakfast quality (higher adherence to Mediterranean Diet) had lower waist circumference, higher HDL cholesterol, and better kidney function

You can see the paper itself here in the Journal of Nutrition, Health, and Aging:

Breakfast energy intake and dietary quality and trajectories of cardiometabolic risk factors in older adults

What this means

According to this research, the heart-healthiest breakfast is:

• not skipped
• Mediterranean Diet adherent
• within the range of of 20–30% of the total calories for the day

Want to make it even better?

Consider:

Before You Eat Breakfast: 3 Surprising Facts About Intermittent Fasting

Enjoy!