Quick Answer:
On a low carb high protein diet you are eating less carbohydrates and more protein to stay full longer. When you cut carbs and increase fat and protein, you are minimizing your intake of sugar and carbs. These stabilize the bodies blood sugar and decreases the amount of insulin that is produced. Insulin is a fat storing hormone, without it your body will increase the amount of fat that it burns.
Full Answer:
What are Carbs?
Carbohydrates are floury/sugary foods that include pasta, bread, cake, desserts, etc. These foods give you a high spike in insulin when your body breaks the carbs down in your body. Carbs are a fast burning energy meaning that your body burns these macros before any of the other macros, fat and protein in your body. When you eat carbs your body breaks it down into glucose, sugar, and uses it. If you have over consumed sugar and carbs the excess glucose will get stored as fat for later use.
When you cut carbohydrates, your body goes into Kenosis and starts burning the next fastest burning macro, fat. It will use up the small amount of carbs that you do consume and will fill the deficit with stored fat. This is how the low carb, high protein diet leads to weight loss. If you deplete both carbs and fat, your body is forced to get energy from your muscles, protein. That is why you eat a high fat and high protein diet when you cut carbs. It is generally recommended with a low carb high protein diet that 30%-50% of your daily calories come from protein.
Cutting Carbs
When you start a low carb diet, you will feel foggy for the first few days as your body changes from using carbs as its main source of energy to fat. If you are trying to get more protein there are many food options meat, fish, beans, healthy oils, eggs, and above ground vegetables are some of the ingredients you can use to prepare meals. This should be a sustainable change in eating and not a temporary weight loss solution. Always consult a doctor before trying out a low carb high protein diet, as there are some health issues that do not benefit from this type of diet.
References: WebMD, DietDoctor, ConsumerReports