Is it true that you can burn more calories by waking and exercising in the morning before eating?
The number of calories a person burns during exercise is a product of his heart rate and the time spent at that heart rate. A person exercising for 30 minutes at 165 BPM will burn the same calories whether it is performed at 8:00pm or 8:00am.
On a similar note, the typical argument for morning exercise is that it will result in more fat burning. The explanation is that after a night of sleep, glycogen stores (in the liver) are low. If one performs cardio exercise before eating, the body will use a higher percentage of calories from fat.
In reality, while the percentage of fat used during exercise may vary depending on how much carbohydrate is available, the most important thing for a client seeking fat loss is how many calories are burned. The more calories used during exercise, the more stored fat can be lost if the exerciser is consuming fewer calories than needed.