A common fat loss strategy used by many fitness enthusiasts and those trying to lose weight is to perform cardiovascular exercise early the morning on an empty stomach. This strategy was popularized by Bill Phillips in his book, “ If the body is already low on energy it has to use fat as energy instead the carbohydrates sorted by the body. I have implemented this strategy into my own training program in the past, with mixed results.
While this theory sounds great, it doesn’t look at the big picture. The body is continually burning or storing energy all throughout the day. It is more important to training using exercises the jump start your metabolism instead of focusing on exercises that try to use more energy in that given time period. For example, a person may run on the treadmill and burn 250 calories on an empty stomach and the majority of those calories would come from body fat. Another personal may run on the treadmill and burn 250 calories but because they had a pre-exercise meal most of the calories would come from stored carbohydrates in the body. Either way 250 calories of energy was used. At the end of the day it makes no difference because the body will store any excess energy as fat. And in turn the body must burn more energy than it takes in to lose body fat. It is the total amount of calories that an individual takes in and the total amount they burn that matters. In fact training on an empty stomach might actually hinder fat loss.
If an individual is low on energy it is hard if not impossible to train at an elevated intensity. Multiple studies have shown that a pre-exercise meal allows individuals to train more intensely compared to those that exercise on an empty stomach. Training harder and jump starting your metabolism will burn more total calories thought out the day and help reach The American College of Sports Medicine recommendation of 150-250 minutes per week of physical activity for weight loss and the prevention of weight gain. The take home message is that it is more essential to worry about the about on energy you burn the 23 hours a day you are not at the gym, than to worry about how may calories or what type of energy you are using while in the gym.
What about my personal experience? Well, I never saw any drastic changes exercising in the morning on an empty stomach; however I did like to wake up and start moving. It put me in a good mood and made me feel better the rest of the day. So while I don’t think working out in the morning on an empty stomach will help burn more fat; if you like to work out in the morning and don’t have time to eat or if eating before working out upsets your stomach, go for it, but eating something small 1-2 hours before may be beneficial.