A low-carb diet restricts carbohydrates, like sugar, bread, pasta, and starchy vegetables, focusing instead on protein, healthy fats, and non-starchy vegetables (meat, fish, eggs, leafy greens, avocado) to encourage the body to burn fat for energy, aiding weight loss and potentially improving blood sugar control, with carb limits ranging from under 50g (ketogenic) to 100-150g daily. It emphasizes whole foods and fiber, avoiding refined carbs, and is a popular strategy for weight management and metabolic health.