An endocrinologist explains what happens if you eat breakfast after nine: "The body interprets it as a sign of stress."

Just as important as breakfast is eating it at the right time. Breaking the nighttime fast after nine in the morning can have negative consequences for your health, says endocrinologist and social media personality Francisco Rosero.

" Never eat breakfast after 9:00 a.m. if you want to improve your metabolism," this specialist explains in a video posted on his Instagram profile.

The reason, he says, is cortisol , also known as the "stress hormone." "We produce small amounts of cortisol to wake up and be energized in the morning," Rosero says.

That cortisol spike, he continues, "starts at 4:00 a.m. and rises until 8:00 or 9:00 a.m. , at which point it reaches its maximum level and then begins to decline."

If you don't eat breakfast before 9 a.m., "the body interprets that fasting as a sign of stress ." This not only prevents cortisol levels from starting to drop, "but also keeps them high," he adds.

Faced with this excess cortisol, "the body itself begins to produce glucose, raising blood sugar levels ," notes the endocrinologist, which is why he recommends having breakfast early "to prevent our body from interpreting fasting as an alarm signal to keep cortisol levels, which is the stress hormone, elevated."

Regarding the ideal time to break the fast, Rosero says it's " between 7:00 and 8:00 in the morning." She also reminds us that the best way to break this fast is with protein, and she makes special mention of eggs, Greek yogurt, and cheese as three ingredients that can be included in any healthy breakfast.

"Of course, also with salmon, meat or chicken , and if you are vegetarian or vegan, with legumes , a very good source of protein," he concludes.