Me.. If My BMI is less than 18.4 I am underweight for my height. I'm I eating enough calories every day? People who are underweight may be at risk from health problems, including loss of bone density, malnutrition and irregular periods (women). However, I may be naturally slim and will not need to change my eating habits. The best way to ensure that my weight is healthy for my height is to speak with my GP. Try to get up to my ideal weight if I can. I can up your calorie intake but make sure you're eating a healthy, well-balanced diet. Some types of exercise burn more calories than others so make sure I'm eating more calories than I'm using. I edited the You, You're, ECT.. That's what was said about me . P.s My height is: 5 feet and 8 inches. My weight is: 7 stone and 13 pounds. BMI.. 18.4?? Underweight?? Is anybody been called Obease(sp) yet??