In light of this, there has been a recent push back against the idea that working out fasted can better promote fat burning. One such researcher is Javier Gonzalez, a professor of nutrition and metabolism at the University of Bath, who provides some excellent context on this important topic. He admits there’s more than “an element of truth to that.” Gonzalez’s research shows that training in a fasted state can improve metabolic health. It indicates possible benefits in muscle remodeling.
Gonzalez points out that in many cases, fasting prior to exercise will provide benefits you wouldn’t otherwise see. The most important thing is just to get out and be active. “The most important thing is to do the exercise. Whether you do it fasted or fed is just the icing on the cake,” he explains. This claim highlights the importance of moving our bodies, no matter if a person has eaten prior to or not.
His research suggests that training in a fasted state makes modest improvements in metabolic health. Fasted workouts have been shown to increase muscle adaptation to exercise. This increase is especially important for those who want to improve their health. In addition to increasing insulin sensitivity, training while fasted can increase your body’s ability to handle sudden blood sugar increases. These types of spikes can sometimes cause energy crashes, so it’s important for each person to be aware of how their body reacts to exercise in general.
Gonzalez suggests that people who want to try fasted exercise should ease into it. He suggests starting with just 15 to 20 minutes of movement and working up to longer periods of time as you get stronger and more fit. He warns people to pay attention to what their bodies are telling them while working out. “If you feel light-headed or dizzy, that’s your cue to stop and eat something,” he notes, emphasizing the importance of personal well-being during exercise routines.
Moreover, Gonzalez highlights a critical concept regarding energy balance: “We can only store a small amount of carbohydrate as glycogen in our muscles and liver. Any extra energy – from carbs, fat or protein – eventually gets stored as body fat. So to lose fat, you need to be in an energy deficit: burning more energy than you consume.” In it, he explains why keeping an energy deficit is important. So if a person doesn’t, the advantage of cardio fasted starts to disappear because your body will settle its energy levels with time.