how many calories should i eat a day if i'm trying to lose weight
This means that whatever your daily calorie maintenance level is, you need to eat about 20% BELOW that amount per day. Here's an example. Let's say your daily calorie maintenance level is 2500 calories. In this example, you'd first see that 20% of 2500 is 500. That means you'd need to eat 500 fewer calories per day, which in this example means you'd need to eat about 2000 calories per day in order to lose fat at the ideal rate.