It contains proteins, fats, carbohydrates, even, but in moderate amounts. It can be used very long time.
Breakfast: unsweetened coffee with milk.
Lunch Time: 250 grams of meat boiled or fried without oil, lemon, 40 g of rye bread, an apple, a cup of unsweetened coffee or tea.
Dinner: 200 grams of fried chicken without fat (on a lattice), 40 g of rye bread, apple.