Calculate your BMR, there are calculators online that will do it. This will give you a ball park figure, add to that calories burned from cycling. Most HR will give you a ball park figure based on your heart rate. The ones that take in to account your weight, max HR, age, sex are more accurate, but it is still just a ball park figure. Then just track your weight and what you eat. For healthy weight loss you want around 500-600 calories deficit. Also try to incorporate weight training and core muscle exercise as not to loose muscle mass.
From what you posted you might not be eating enough for your weight and age. Nutrition and eating healthy is a very important part of weight loss. Personally I would recommend replacing the bar with actual food. Bagel is ok, but it's mostly just carbs. If you do choose a bagel go for whole grain one.
UD
Last edited by UmneyDurak; 10-20-09 at 12:58 PM.