The Clue Low-carb, high-fat (or perhaps high-fad) diet
The Answer KETO
The answer "KETO" refers to the ketogenic diet, which is known for being low in carbohydrates and high in fats. This diet encourages the body to enter a state called ketosis, where it burns fat for energy instead of carbs. Many people follow the keto diet for weight loss and health benefits, but some critics consider it a fad. Overall, "KETO" perfectly matches the clue about a low-carb, high-fat diet.