Is the hype really worth it?
There has been a lot of hype around fasted workouts recently. If you are new to the game, this is when you complete a workout without having any food in your stomach. This is typically the case for morning workout or cardio sessions.
While some swear by these empty stomach sweat sessions, there are many questions swirling around the topic. Advocates claim that fasted workouts will help increase fat burn, but what does science say about it?
Let’s first look at the science behind why people believe that fasted training works. When you are fasted your blood sugar levels and glycogen levels are low. With lack of glycogen stores it is believed that our body will tap into fat stores to fuel the workout. This theory (backed mainly by the bodybuilding community) sounds like a great tradeoff for those who love their early morning workouts. Skip your pre-workout snack + burn more fat. Solid plan, right?
Let’s just say there were many skeptics out there so several scientific studies have put this theory to the test.
science behind calorie burning
Let’s think about something before we dive in. How do you actually lose fat? Well, to lose fat you have to burn calories. Consuming more calories than we burn (caloric surplus) = weight gain. Burning more calories than we consume (caloric deficit) = weight loss. Our own metabolism will play a major role in how our bodies decide to use the energy we consume for fat loss.
One study looked at fasted cardio compared to postprandial (after eating) cardio in terms of energy intake. The participants performed 60 min of cardio (treadmill). Conclusions showed that there was no difference in the amount of calories burned in fasted vs postprandial cardio and those who ate breakfast before their workouts actually indicated having more appetite suppression.
Bottom line: Not eating breakfast before your workout does not automatically mean you will burn more calories. Burning more calories is what is necessary for weight and fat loss. **Remember caloric deficit = weight loss**
science behind appetite & energy
Another study looked at the affect fasted training had on appetite and overall energy. The participants in the study who were able to eat breakfast before their workout indicated that they had better appetite control throughout the day compared to those who did the fasted training. This appetite control ultimately led to less overall daily caloric intake.
Bottom line: The individuals who ate breakfast before their workout had better control over their appetites and burned more calories than they consumed thus putting their bodies in a caloric deficit (weight loss). Those who fasted before their workout reported having a harder time controlling their appetite throughout the day.
At the end of the day, it all comes down to preference. Do you like working out on an empty stomach or not? Because let’s be serious, fasted training boils down to bro-science.
Instead of focusing on fasting, focus on calories in vs calories out. All our bodies are different, but at the bare bones of it all, we have to be in a caloric deficit to lose weight. If we are putting more calories in than we are putting out we are going to gain weight.