I was told to exercise at a low heart rate within the "fat burning zone" to lose weight. I exercise five times a week in the "fat burning zone," eat moderately, but I am losing very little weight. Please help me!

Help is only a few extra heartbeats away!

It is true that when you exercise at a lower heart rate (at 50% of aerobic capacity), you are burning a higher percentage of fat per single Calorie expended. When you exercise at a higher heart rate (at 70% of aerobic capacity) you are burning a smaller percentage of fat per single Calorie expended, however you are also breathing in more oxygen. More oxygen consumed equates with more total Calories burned, because for every liter of oxygen taken in, 5 Calories are expended. Therefore, a smaller percentage of fat used per Calorie, multiplied by more total Calories expended, equates to more total fat being used and promotes increased weight loss.

To summarize, it is not necessary to slow down your heart rate if you can maintain the pace for your desired workout time. Exercising as hard as you are comfortably able optimizes total Calories and fat burned.