Fad diets are popular eating plans that promise quick weight loss or health benefits but often lack scientific support. These diets typically focus on specific food groups or eliminate others entirely, making them difficult to maintain long-term. Examples include the Atkins Diet, Keto Diet, and Paleo Diet. While some people may experience short-term success with fad diets, they can lead to nutritional imbalances and unhealthy eating habits. Many experts recommend a balanced diet that includes a variety of foods, rather than relying on restrictive diets for sustainable weight management and overall health.