Okay, I just deleted a bunch of advice and admonitions about what I think you should not be doing - starving yourself into malnutrition, trying to rid yourself of perfectly good muscle, yada, yada... Not that I don't think that stuff is (vitally!) important, but earlier responses have covered that ground pretty well.
Let's move on to what you can & IMNSHO should be doing:
Quote:
...decided to slowly switch to vegan diet to see what it does. But after a while of thinking this seems thousand times harder than switching to vegetarian diet, which won't be so hard for me, because I don't like meat so much since my early childhood. In fact I eat only chicken breast and some sea fish, both being the least meat-tasting kinds of meat. But in case of vegan diet I have to get rid of everything originating from animals, such a hard restriction when cooking. But I will work it out.
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Excellent! Great Idea!
It sounds like you're a natural vegetarian, and will do well with it. You can slowly add more and more vegan components to your diet (tofu instead of soft cheeses, that sort of thing) over time. The things to watch out for when going vegetarian are making sure you get proper amounts of protein (beans, peas, nuts, soy, eggs, cheeses, etc), making sure you don't get too much fat (lots of yummy vegetarian dishes have surprising amounts of fat), and - conversely - making sure you get *enough* fat.
There are certain vitamins (A, D, some of the others) that the body can only absorb with the help of some fat. Too little fat means your body can't get the vitamins it needs. "Enough" fat isn't very much (say, 75 to 120 gm/day), but you need that minimum.
Exercise:
Toned muscles tone look better & skinnier than slack & flabby muscles. You just want the type of exercise that makes muscle long & strong, not big & "pumped."
Check out high-rep/low-weight strength training methods, which makes your muscles stronger without making them bulky (this may be even something you can opt for in PE). Yoga, Pilates & Alexander Technique are all also good for getting yourself looking long & lean.
Clothing:
The boy in the pictures is making himself look even skinnier than he is by -
- wearing black
- emphasizing long vertical lines
- contrasting close-fitting pants & shirts with large, loose, flowing overgaraments
- tailoring his body-skimming clothing to fit closely, but still show ease and a a few bags & folds
- contrasting his skinny clothing with big platform shoes and a thick, volumized hairstyle
Put that boy in red & blue horizontal stripes and baggy jeans, give him some Keds, and slick his hair down; and - well, he wouldn't look stout, but he might look just about the slender side of normal.
Good luck to you, & I hope this helps.