Morning Workouts on an Empty Stomach Are Not a Means to Burn Fat
I did morning cardio on an empty stomach and I understand why this is necessary. It’s like such a virtuous act: you make yourself suffer, and it’s hard, but not impossible. You finish your morning run on an empty stomach and then reward yourself with a hopefully delicious breakfast. But is there any point in suffering?
From time to time, studies appear pointing to fasted exercise or, more recently, morning exercise as the secret to fat loss. The latest study to make headlines was in mice, and found more evidence of fat burning in samples taken from mice after they were made to run on a treadmill “in the morning” compared to mice that exercised in the morning. evening.” The study found that fasting didn’t matter to the mice, only the time of day.
(Fun fact about rodent circadian research: mice are active at night and sleep during the day, so the results are always reversed when we describe how they might apply to humans. The “morning” exercise was done in what would be evening for us.)
For people, morning workouts and fasted workouts often go hand in hand, and fasted morning cardio is becoming an increasingly popular weight loss recommendation. But is it really more efficient? Personally, I love to sleep these days, and I won’t go back to that morning exercise just because of a few extra metabolites in the body fat of a few rodents, but let’s talk about whether this and other supposedly fat-burning forms of exercise actually mean anything. anything in the big picture.
Burning fat during exercise is not as important as you think
If you want to lose weight, fat burning is good, right? But just because you’re burning fat doesn’t mean you’re losing fat overall. I like to think of fat as a wallet: you can take some energy out of there and “spend” it, but later in the day you can put more money (or energy) back in. What matters is how much you have. to your bank account at the end of the day, week or month.
Similarly, it doesn’t matter what kind of fuel you burn during your workout. Whether you’re burning fat with low-intensity cardio in the morning on an empty stomach or carbs with HIIT in the evening after taking Gatorade, your body will balance one way or another. Burn more calories than you eat and you’ll have to lose that energy from somewhere – hopefully fat. Eat more than you burn, and vice versa.
Scientific studies examining whether fasted cardio causes total fat loss generally do not find a significant difference between training with and without food. This study , for example, found no difference between groups of people who showed up on an empty stomach and received a shake before or after their morning run.
Looking at the bigger picture, this review concludes that “there is no strong evidence for the superiority of fasted cardio versus cardio to improve body composition,” and warns that too much fasted cardio—say, for an hour—may actually cause body to eat muscle reserves for fuel. So if you’re really into fasted cardio, this strategy can backfire.
Morning cardio on an empty stomach has disadvantages
If you train early and don’t always have time to eat, that’s probably fine – you won’t kill your gains. But if you can eat first, chances are you’ll have a better workout.
Low-intensity cardio (zone 2 on the five-zone scale ) tends to use mostly fat for energy, so you may not even notice the difference whether you do it with or without a good pre-workout meal. Even if you find it difficult to complete an easy morning jog the first time you try it on an empty stomach, your body may adapt a bit over time. Many people have a habit of jogging before breakfast, and that’s okay – maybe not optimal, but good.
But once you start working out at a higher intensity, you’re likely to miss out on those carbs. Having glycogen in your muscles or breakdown products of carbohydrates in your veins (called blood sugar) will make you feel less tired and allow you to work harder. Ultimately, if you train better with food than without, why not give yourself enough fuel for that workout?