Today was a very tireding day.

I've been reading about protein.

Protein is very important for the people.

I prefere the natural protein, like afrom eggs.

Bodybuildingers usinge protein in biglarge quantities, but for the rest of the people, that is not necessary.

For things which are general facts, simple present tense works better than the progressive. So, "bodybuilders use protein" instead of "bodybuilders are using protein."

"Big" is usually used for physical size (height, width, and volume), but feels awkward when used for numbers and quantities. "Large" might work better here.

Here, instead of "the people", I might say "us": "...but for the rest of us..." This might sound more natural.

In the supermarket exist, there's so many protein products in abundance, it's so crazy.

Today was a very tireding day.

I was reading about protein.

Protein is very important for the people.

I prefere the natural protein, like a eggs.

Bodybuildings using protein in big quantities but for the rest of people is noers eat large quantities of protein, but for most people that isn't necessary.

In the supermarket exist protein products in abundance, its soThere are so many protein products in supermarkets that it's crazy.

Today was a very tireding day.

I was reading about protein.

Or you could also say " I read about protein"

Protein is very important for the people.

I prefere thea natural protein, like a eggs.

Bodybuildings usingers consume protein in big (large) quantities, but for the rest ofmost people it is not necessary.

In the supermarket exist protein products in abundance, its so(grocery store), there are so many protein products it's crazy.