The Downsides of Doing Cardio before Breakfast
Research shows that if you eat a carb meal before doing low-intensity exercise you’ll burn less fat than you will if you fast beforehand. On the other hand, the effects seem to be different in trained individuals who work out at a moderate-intensity or greater compared to less fit people.
When fit individuals train at 65% V02 max or greater, research shows it doesn’t interfere with the body’s ability to use fat as fuel, while in untrained individuals it may have a fat-sparing effect. This suggests that once you reach a certain level of fitness and are working out at a moderate-intensity, eating a modest breakfast before you start working out won’t have a negative impact on your body’s ability to use fat as a fuel during exercise.
Why It’s Better to Eat Breakfast Before Your Workout
There are some upsides to doing cardio after eating a carb meal. Recently a study was carried out by researchers at the University of Padua in Italy. They found that individuals who ate before working out burned more total energy including fat for a full day after they had completed their workout.
Eating before a morning workout makes even more sense if you’re doing high-intensity exercise or interval training. When you do high-intensity exercise, your body is anaerobic for periods of time. This forces it to use carbohydrates as a fuel source. If your glycogen stores are low, you won’t be able to push yourself as hard. This means you’ll burn fewer overall calories and less overall body fat if your glycogen stores are depleted.
High-intensity exercise where the body is forced to tap into carbohydrates as a fuel source creates an oxygen deficit. This means your body will burn greater amounts of energy for hours and even days after you stop working out. But if you’re carb-depleted, you’ll struggle to work out at this intensity and won’t get the benefits.
What does this mean? Unless you’re doing cardio at a low-intensity like walking on the treadmill, there are few benefits to not eating before your workout. Quite the opposite. If your goal is to work out hard, carbohydrates improve your performance and allow you to maximize the intensity.
The Bottom Line?
If it’s a rest day for you, and you’re doing low-intensity exercise, do it in a fasted state. In this case, you’ll use more fat as fuel. If you plan on increasing the intensity, especially if you’ll be doing high-intensity exercise, have a small pre-exercise meal of lean protein and complex carbohydrates about an hour or two before your workout. Good choices are a bowl of oatmeal with low-fat milk or an egg on whole grain toast. You’ll feel better, and you’ll be able to exercise harder too.
References:
J. Applied Physiology. 1986; 6: 165-72.
Am. J. Physiol. 1999 May; 276(5).
J. Appl. Physiol. 1976; 41:683-88.
Shape Magazine. August 2011. page 106.
Related Articles By Cathe:
4 Things to Consider if You Exercise in the Morning
4 Types of People Who Benefit Most from Working Out in the Morning
Are Mental Blocks Keeping You from Getting Your Fittest?
Tips for Making the Transition to Morning Exercise
The only problem for me with this is that I workout at 5 a.m. I can’t wake up at 3 a.m. just to eat breakfast. Plus I find that if I eat before intense cardio, I feel sick to my stomach.
For MC: I just eat 1/2 of a Zone bar or other carb & protein bar before my workouts. It is only about 100 calories, but does help with energy.
I have found this to be very true…my ideal workout time is 11:00am. I try to eat a good breakfast around 8:30 – 9:00am, and then drink plenty of water for the next 2 hours. I warm-up/light stretch and then do HIIT on my elliptical for 50 minutes, followed by a cool-down and light stretching. I am drenched at the end!
I have tried to do my workout right in the morning and find I simply have no energy and feel sick to my stomach. Everyone has to do what works for them.
MC, I’m in the same boat as you. I work out early, its the only time that I can fit it in, but I sure don’t want to wake up at 3 AM, eat breakfast and then try to go back to sleep on a full stomach. I would love to workout later in the morning after breakfast and when I really alert and awake, but its not possible. I would love to know what is something quick that I could eat, say 30 minutes beefore working out? Should i eat something different on cardio days and weight days?
In reading an article by Dr. Bob Arnot, I saw that he recommended having a protein drink 15 minutes before working out. I have found when I am forced to workout early in the morning, this has helped me a lot. For me, working out on a totally empty stomach makes me feel queasy and light headed, and I really notice a difference in my energy level. I have found it works better for me to eat at least 1-2 hours before working out, however, that is not always possible. So when I have to have an early a.m. workout, when I get up, before I even dress for my workout, I drink an 8oz protein powder drink and another 8oz of water before I even hit my home gym and this has been very effective.
This article makes such sense to me!
Same issue here, wake up at 5am to workout, but I also have thyroid medication that causes me to have to wait an hour after I take it before I eat. I wish I could eat before working out, but at this rate, I would never make it to work in the morning! I guess the most important thing to remember is that some workout is better than not working out at all!
I’m the same way, and sometimes the stomach aches last for hours..
I can work out MUCH harder in the morning if I have a little bit to eat. If I’m short on time and can’t eat an hour ahead, I have a glass of orange juice mixed with chia seeds, which provide high-quality protein, omega-3s, and a bunch of other really great stuff. I like to let them dissolve a bit–they plump up into the consistency of tapioca. (Sometimes I combine them with the oj the night before and keep the mixture in the fridge.) I’m convinced chia seeds are just about perfect — I mix them into baked goods, cereal, yogurt, salad dressing, smoothies, even meatballs. I first read about chia in the book Born to Run and have done a lot of research on them since. I buy bags of organic chia seeds at Whole Foods or other natural food stores, but they’re also available through several online retailers.
I work out much better on an empty stomach. Sometimes I can eat something light only when I am doing weights. When I do cardio…I only have my coffee and water and I am good. I am used to it.
Interesting. I just read the complete opposite in a book by a professor and research dietitian at Brown University (The Pink Ribbon Diet by Mary Flynn). She says, “I suggest delaying breakfast because when you wake up in the morning, your insulin is as low as it will be for the day and your body will use stored fat for energy. When insulin is low, the enzyme hormone-sensitive lipase, which works to release fat from fat cells, is turned on; after a meal, when insulin is higher, the enzyme lipoprotein lipase, which is used to take fat in, takes over. For that reason, it is extremely beneficial for weight loss to exercise in the morning before you have eaten.”
Research tends to go back and forth. All I know is that when I eat a couple of eggs and toast, I’m able to jump higher and step longer than if I do not eat. I try to eat at least 30 minutes before doing cardio and 60 minutes before my weight work out days. Everyone needs to find what works best for their body.
I workout very early also at 5:30am, but I always eat a snack before exercising since I don’t have time for a full breakfast before an early workout session. I usually have a Zone bar or a Balance Bar. I eat half of the bar or the whole bar depending on the length and intensity of the workout. I once exercised on an empty stomach, but the more fit I became, the more hungry I felt during my workout and that hunger became a distraction. I feel so much better now that I have a snack before exercising and I notice that I have better stamina and energy for my workout.