The amount of weight you can lose during a 24-hour fast depends on several factors, including your current weight, body composition, metabolism, and individual variation. 

During a 24-hour fast, your body primarily relies on stored glycogen (carbohydrate stores) for energy. Glycogen is stored with water, and when you fast, your body depletes glycogen stores and releases some of that water weight. This initial weight loss is mostly water and not fat loss.

In terms of actual fat loss, it’s difficult to estimate an exact amount for a 24-hour fast. Generally, during a short-term fast, most of the weight loss will come from water, glycogen depletion, and some minimal fat loss.

It’s important to note that any weight lost during a 24-hour fast is likely to be temporary and may be quickly regained once you resume eating. True sustainable weight loss typically occurs through long-term changes in diet, exercise, and lifestyle habits.

Fasting can be a tool for weight loss and can help some individuals manage their calorie intake. However, it’s essential to approach fasting with caution and ensure you’re meeting your nutritional needs when you do eat. It’s advisable to consult with a healthcare professional or registered dietitian who can guide you on safe and effective strategies for weight loss based on your individual circumstances and goals.