You need to eat enough protein to build muscle, and enough of the good carbs to fuel the fat burning process. The good carbs also provide some nutrients that your body and brain needs, so don't skimp on them.
You also need to eat a healthy breakfast to start the daily process, and to keep yourself from crashing your blood sugar levels. Water alone is a lousy breakfast. By itself it has no nutritional value for your brain or body, and provides no energy to them, either. The milk and salad for lunch are fine, as long as you include some type of protein and good carbs. The milk doesn't provide enough protein on it's own, but is a help. If you don't care for what your mother prepares for dinner, then make your own healthy meals and eat that, but don't skip the meal. Skipping meals upsets the blood sugar and other levels in the body. It's just not good for your overall biochemistry, and will have a negative effect on your exercise regimen. You can't exercise as well, when you don't put enough fuel in your tank. As long as you eat mostly healthy foods in enough quantity, and often enough, and exercise you don't need to worry about specific calorie counts. Starving yourself makes people tired, cranky, and prone to getting sick. Also, the skeleton look is hideous. So please eat more than you've been doing for your own sake. Just eat healthy while doing it. And don't deprive yourself of an occasional "naughty" food that you happen to like. Treating yourself to an occasional "bad" food won't instantly turn you into a blimp or give you a heart attack. Food is one of the nicer ways to enjoy life. Meal times shouldn't seem like a punishment.
Enjoy your meals, your health, and your life.
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If a man does not keep pace with his companions, perhaps it is because he hears a different drummer.
Let him step to the music which he hears, however measured, or far away.--Henry David Thoreau