If you want the short answer, to lose weight you should be eating between 1000-1400 calories per day. Women need less, usually around 1000-1200, while men can do a little more and eat about 1200-1400 and still lose weight. That's the simple truth. If you are stuck and can't lose any more weight, cut out another 150-200 calories per day.
Previously, the FDA and various government agencies have thought that people should be consuming around 2000-2200 calories per day. Take a look below to see the government recommendations and guidelines.
According to the FDA, the table below shows how many calories a typical male needs. For women, subtract about 200 calories.
You will notice that up until age 20, we will require more and more calories. But then our metabolism starts to slow down. By the time men reach their 50s, they rarely require more than 1400-1600 calories per day if they are sedentary. Women, even less.
How much do we actually eat? Take a look at the below graphic to get an idea of how many calories we think we eat, compared to how many we actually eat.
As you can see, most people think that they only eat about 1000-1200 calories per day, while really consuming 2000-2500 calories per day.
Further, most people severely underestimate the amount of calories they actually burn.
Let's be realistic and realize how much we are really eating and how much we are burning. Do we really need all those calories?