Ăn thực phẩm giàu chất béo không bão hòa. Ăn ngũ cốc nguyên hạt hoặc lúa mì nguyên hạt giàu cacbon-hydrat. Dùng chế phẩm từ sữa động vật nguyên béo. Kết hợp thịt vào chế độ ăn một cách khoa học. Tăng cường nguyên liệu giàu calo vào món ăn.

Given the above summary, write a detailed text in English for it.
Of course you'll need fat to increase your body weight, but not all fats are the same. Saturated and trans fats will help you gain weight, but they'll also increase your cholesterol and your risk of heart disease. Unsaturated fats, however, help reduce your risk of heart disease and boost your immune system. Make sure every meal you have includes some fat.  When gaining weight, you'll want to focus on these "good fats" to help beef up your body fat while still getting necessary nutrients that your body needs.  Nuts, peanut butter, fatty fish like salmon and mackerel, and avocados are all high in unsaturated fats and calories and will still provide you with essential nutrients. Include these in your meals or snack on them throughout the day. Carbohydrates act as energy sources for the body. If you don't burn off the energy, it will be stored as fat and help you gain weight. After fat, carbs are important contributors to weight gain, so you'll need plenty of these in your diet.  You should focus on whole wheat products for your carbs instead of white products. White products are bleached and processed, which removes most essential nutrients. Whole wheat products will give you the carbs, plus fiber, vitamins, and essential minerals.  Replace white products with whole wheat bread, pasta, and brown rice. Include carbs in all your meals to help in your weight gain. Dairy is important for your diet because it contains calcium and vitamins. Most dairy products come in reduced-fat varieties, but you'll want the full-fat versions to increase your calorie and fat intake. Drink whole milk and eat cheese and yogurts made from whole milk.  Replace sugary sodas (which have no vitamins or nutritional value) with a glass of whole milk to increase your fat intake while nourishing your body.  Keep in mind that these types are higher in saturated fats. There is, however, some evidence that full-fat dairy products actually decrease the risk of heart disease. The protein and fats you get from meats are important for gaining...