How much weight will I lose if I don't eat for a day?

 If you skip eating for a day, any weight you lose will likely come from water weight rather than fat. Here’s how it typically breaks down:

1. Water Weight: Much of the initial weight loss is water. When you reduce food intake, your body uses up glycogen (a form of stored carbohydrate) for energy, and glycogen holds onto water. For each gram of glycogen burned, you lose about 3 grams of water, so this can lead to quick weight changes. You might see a 1-3 pound decrease from water loss.

2. Fat Loss: Losing actual body fat in a single day without food is minimal. You need a calorie deficit of about 3,500 calories to lose a pound of fat. In one day, you'd typically burn between 1,500 and 2,500 calories, depending on your metabolism, activity level, and body composition. So any fat loss would be a fraction of a pound.

3. Muscle Mass: If you’re fasting for more than a day, your body may start breaking down a small amount of muscle for energy, especially if you aren’t getting enough protein regularly.

For long-term weight loss, it’s usually better to follow a sustainable eating plan rather than short-term fasting, as quick changes can disrupt metabolism and muscle retention.