But a number of surveys shows that it's a really important meal.

It's even considered as the most important of the day.

Maybe you were trying to say "It's even considered of the most important of the day."
which would mean that there are other meals that are considered more important, but among all meals, breakfast is amongst only the most important of them.

A meme says "Breakfast like a king and dine like a paurer".

I'm not sure what paurer means.

It means you have to eat a lot in the morning and eat less food in the afternoon or in the evening.

Though "in the afternoon or in the evening" is correct, the second "in the" is redundant and can be omitted.

If you want your body to burns the fat and the calories, you'll have to eat early as your body will be mortter be able to metabolisze (that means your blood sugar level won't spike as high).

"the fat" and "the calories" sounds like there is 1 specific "fat and calories" that you want to burn, however to make the sentence mean "to burn fat and calories in general," you need to omit the "the."

The second reason is that if you eat a breakfast, you will be mortter be able to control your appetite, and it's healthier.

Moreover, a survey demonstrateds that people who have breakfast every day are leaner than those othersat don't.

"demonstrated" implies that the survey used to demonstrate, but now no longer does. "demonstrates" implies that it is still currently demonstrating the results.

Thanks a lot for reading my work and correcting me.

Tell me how you found my English and feel free to give me advices!

"Advice" is both plural and singular.

But a number of surveys shows that it's actually a really important meal.

"shows" -> "show" because "surveys" is plural.
"actually" is optional, but it helps emphasize the contrast between this and the previous sentence.

It's even considered asto be the most important of the day.

"considered" is usually used with "to be". In fact, you can even omit "to be" and just write "It's even considered the most important meal of the day."

A mem says "Breakfast like a king and dine like a paurper".

What is a mem?

It means you have toshould eat a lot in the morning and eat less food in the afternoon or in the evening.

Have to implies that it's a must, that it's necessary. "should" reinforces the idea that it's a suggestion.

The first reason is the metabolism.

If you want your body to burns the fat and the calories, you have to eat early as your body will be more able to metabolise tmore efficiently. That means your blood sugar level won't spike as high.

Or "...metabolize more efficiently, meaning that your blood sugar level won't spike as high."

The second reason is that if you eat a breakfast, you will be more able to better control your apetite and it's healthier.

Moreover, a survey demonstratrevealed that people who have breakfast every day are leaner than the othersose who don't.

Word choice! Demonstrated is usually not used with surveys, as they don't exactly show actions, behaviours, etc.

It's even considered as the most important one/meal of the day.