To calculate your personal calorie requirements a little more accurately, you might want to try the
University of Minnesota's K-Calculator.
What
happens if I eat a very high-calorie diet?
The exact number of calories you
need to eat daily to maintain (rather than lose or gain) your current weight
depends in great part on how active you are -- very active people can consume
many more calories without gaining weight. However, if you habitually consume
more calories than your body can burn off, you will gain weight, and may become
obese. Complications from obesity include high blood pressure, heart disease,
diabetes, cancer and degenerative arthritis.