One of the biggest debates in the fitness world revolves around the claim that doing cardio before breakfast leads to a greater fat loss then doing so at any other time of the day. The idea is that when you do cardio in the morning before you had anything to eat, your body is in a fasted mode, not having been fed for over 8 hours, so it has to use more stored fat as an energy source during your workout.
There are conflicting views of experts regarding whether doing cardio before eating breakfast is really an effective way to lose body fat faster. Some recommend it while others say it’s either ineffective or downright counterproductive.
In this post I want to go over some of the relevant research, present both points of view, and share some of the pros and cons such a workout habit might have. Read the rest of this analysis for the complete story.
The Case For Early Morning Cardio
The proponents of doing cardio workouts before breakfast include a number of bodybuilders and fitness experts. Among noted ones is Tom Venuto, author of Burn The Fat Feed The Muscle. He makes the case that this is effective due to a number of reasons:
- When you wake up, your body’s stores of glycogen are very low. Since your body needs to use more calories for your workout, it simply has to use more of the stored fat it has. This means that you burn more fat calories.
- Doing cardio in the morning gives you a metabolism boost that may last for a few hours into your day. If you do cardio in the evening, the increase in metabolism may be halted as soon as you fall asleep. I find this argument a bit strange as it has no relation to the question of whether you’ve eaten before your workout or not.
- If you eat before your workout, your body has a ready made source of energy from the food you’ve recently eaten and won’t need to tap into your fat stores.
There are several studies which lend credence to the theory that cardio before breakfast is a good way to burn more fat. The first, and much noted, study is one which was done at the university of Kansas in 1985 . This study looked at fat consumption as a percentage of total calorie expenditure when the workout was performed at various times of the day. The study showed that when you workout in the morning you burn more fat then when you do a similar workout in the afternoon.
A more recent study supports this conclusion. In this study, conducted in Belgium , 28 men were put on a high calorie, fat rich diet plan. They were divided into 3 groups: the men in the first group did not exercise at all during the six weeks of the study. The other two groups of men did exercise rigorously, doing running and cycling workouts. The only difference was the time of day in which they did so. One group of men trained after eating breakfast while the other did so before breakfast. The workouts and breakfasts were identical. The results these men got were not.
As this was a high calorie eating routine, the men who did not train gained weight. So did the men who trained after breakfast, but less so than the first group. Only those who trained before breakfast did not gain weight. They also tested healthier in regards to insulin resistance. As you can see, cardio before eating breakfast proved to be effective in this case as well.
The Case Against Cardio Before Breakfast
There are those who claim that training before eating breakfast can be counterproductive. Joel Marion, the author of the Xtreme Fat Loss Diet, claims that this not only doesn’t result in an increase in fat burning but may even be counterproductive. The reason is that if you don’t eat a few hours before working out, your body will simply lack the energy needed to perform a rigorous workout. You will actually burn less calories as a result.
Other experts don’t dispute the findings of the studies I’ve outlined above. They simply state that the overall effect of doing cardio early in the morning is negligible. It is simply not an important question and certainly not worthy of the debate that surrounds it.
Pros and Cons of Early Morning Cardio
- Research does show that you burn more fat by doing so.
- Working out in the morning makes you feel energized, alert, and vibrant. It may help you get better focus and productivity throughout your day.
- Doing a morning workout before breakfast is easier since you feel lighter. You need to wait a while after you eat to be able to train comfortably.
- Training in the morning ensures that you get your workout done. If you wait until later in the day, you may miss your workout for any sort of reason.
- Some people find that unless they eat a few hours before working out that they feel nauseous.
- You may experience a certain weakness during your workout.
- You do need to wake up earlier than usual to do it.
Research shows that doing cardio in a fasted state can help you burn more body fat. However, doubts still persist and it seems as if this debate is nowhere near its ending.
The greater question may not be whether doing cardio before eating breakfast helps you burn more fat but whether it makes enough of a difference to warrant so much discussion. The bottom line is likely to be that intense workouts are what matters. The timing in which they’re performed is of lesser importance.
You should enjoy your cardio. Do cardio workouts which are fun. Here are some tips on how to do that:
1. Wilcox, Harford & Wedel. Medicine and Science in Sports & Exercise, (1985) 17:2.
2. Training in the fasted state improves glucose tolerance during fat-rich diet. Van Proeyen K, Szlufcik K, Nielens H. J Physiol. 2010 Nov 1;588(Pt 21):4289-302. Abstract here.