You may have heard trainers and fitness experts say that if you want to lose weight, the best time to exercise is in the morning on an empty stomach. This advice comes from the fact that 1) your cortisol levels are higher in the morning, and cortisol helps break down fat, and 2) your carbohydrate stores (glycogen) are low since your last meal was likely 10 hours prior. Lower glycogen stores may increase the body’s use of fat for fuel. Based on this, morning exercise before eating seems to make sense, right?
A recent study tested this. On two separate occasions, participants were either fed breakfast before or after walking on the treadmill for 36 minutes at moderate intensity – a typical cardio workout. Respiratory exchange ratio, a number that reflects which source of fuel is being used, was measured before, 12, and 24 hours after exercise. The results were as follows:
- Eating before a moderate cardio workout not only increased the use of fat for fuel, it increased it up to 24 hours after exercise.
- Oxygen consumption was higher up to 24 hours after exercise when breakfast was eaten beforehand. This indicates that more calories were burned due to the pre-workout meal.
- Exercising moderately on an empty stomach did NOT increase metabolism or fat burning during or up to 24 hours after exercise.
Now here’s the part that most people miss… if you’re sluggish and you can’t get a good workout because your fuel tank is almost empty, you won’t burn as many calories – including fat calories. By eating the right foods before your workout, you give your brain the fuel it needs and you can work out harder. This translates to burning more calories during exercise and for the rest of the day. As the above study showed, you’ll even burn more fat calories up to 24 hours later. BUT – this all means nothing if you don’t maintain a calorie deficit by the end of the day. In other words, if your total calorie burn is more than the calories you’ve taken in, you’ve created a deficit of energy which forces your body to use more fat stores. And your waistline shrinks. And your clothes get looser. And you look better. And your body is healthier. And you feel fantastic.
So what’s the ideal pre-workout meal? In the study I referenced here, a balanced meal was given containing 55% carbs, 25% protein and 22% fat. This falls into current nutrition guidelines and is in line with what we’ve found in other studies. And if you’re someone who works out longer than 36 minutes and/or more intensely, eating before exercise is even more important. All athletes, particularly endurance athletes, eat breakfast religiously. Here are some suggestions on what to eat:
- • Toast or bagel with peanut or almond butter
- Peanut butter and banana sandwich
- Cereal with skim/soy/almond milk and fruit
- Yogurt with granola, fruit or nuts
- Meal replacement shake or bar (dotFIT, of course!)
If you’re someone who skips breakfast altogether, you’re setting yourself up for some unnecessary challenges. I’ve seen people in the gym pass out during a morning workout due to low-blood sugar because they didn’t eat. Hopefully this doesn’t happen to you, but skipping breakfast means you’re likely to eat more later in the day, have more cravings and eat irregular meals. You’ll probably feel the effects of low blood sugar at some point – sluggish, grumpiness, brain fog and difficulty concentrating. To compensate, you might reach for that doughnut, candy bar or unhealthy snack from the vending machine and then take in empty calories. All of this hinders weight loss and possibly your day-to-day effectiveness. So, I say eat before your morning workout to avoid all this and instead reap the benefits of burning more fat and boosting your metabolism. And if your excuse is you’re not hungry in the morning, you probably ate too much the night before. Not having enough time is not a good excuse either since it doesn’t take any time to grab a bar and go. You could even plan the night before.
If you find yourself making excuses, I encourage you to stop. Instead, choose to make progress.