450 calorie diet is a very low-calorie diet and is usually used for short-term weight loss or as part of a medically supervised weight loss program. It's important to note that such a low-calorie diet should only be followed under the guidance of a healthcare professional, as it may not provide enough nutrients for the body to function properly. Moreover, such diets are not sustainable in the long term and can lead to health problems if followed for an extended period. Calorie needs based on your age, gender, weight, height, and physical activity level. You can use this template if you want to explain this idea to your audience.