In this month's Muscle and Fitness magazine, there's an article on whether doing cardio before breakfast is a good idea or not. They now think (after a lot of controversy on the subject) that this IS the best way to burn fat after all.
People used to think that cardio before breakfast was good for fat burning because a low blood sugar level would force the body to burn fat for energy. Then later, people said that this was not true at all.
Well, now they think that it IS true that the body will burn more fat during cardio before breakfast, but for different reasons. Apparently, when you wake up, the blood sugar level isn't that low after all. Blood sugar is the brain's primary source of energy, so the rest of the body actually turns to fat for energy. So, during the night, low insulin levels prevent fat storage, and high glucagon levels encourage fat to be released and used for energy. This way, blood sugar is saved for the brain. Thus, the body is in fat-burning mode during the night (although I guess calorie requirements are pretty low while you are sleeping, so you won't necessarily wake up leaner!)
According to the new theory, when you first wake up, the body is still in fat-burning mode, with low insulin and high glucoagon levels. So, if you do cardio before breakfast, your body's primary energy source will be fat. They even say that the effect lasts all day. After each meal, you are less likely to store fat if you did cardio before breakfast.
The drawback (there had to be one!) is that whenever the body is in fat-burning mode, it will also burn some muscle as well. So it may not be the best thing for people trying to maximize muscle size, but may be a good thing during a fat-burning rotation. They say that for someone who wants to build muscle, cardio should be done later in the day (ie not on an empty stomach), preferable on a different day to weight lifting.
I would be interested to hear Maribeth's opinion on all this. I guess new theories come out all the time, and they often turn out to be wrong. Anyway, it has got me interesting in trying cardio first thing. I'm terrible at getting up extra early, though, so perhaps I'll give it a try on weekends...
Sharon.
People used to think that cardio before breakfast was good for fat burning because a low blood sugar level would force the body to burn fat for energy. Then later, people said that this was not true at all.
Well, now they think that it IS true that the body will burn more fat during cardio before breakfast, but for different reasons. Apparently, when you wake up, the blood sugar level isn't that low after all. Blood sugar is the brain's primary source of energy, so the rest of the body actually turns to fat for energy. So, during the night, low insulin levels prevent fat storage, and high glucagon levels encourage fat to be released and used for energy. This way, blood sugar is saved for the brain. Thus, the body is in fat-burning mode during the night (although I guess calorie requirements are pretty low while you are sleeping, so you won't necessarily wake up leaner!)
According to the new theory, when you first wake up, the body is still in fat-burning mode, with low insulin and high glucoagon levels. So, if you do cardio before breakfast, your body's primary energy source will be fat. They even say that the effect lasts all day. After each meal, you are less likely to store fat if you did cardio before breakfast.
The drawback (there had to be one!) is that whenever the body is in fat-burning mode, it will also burn some muscle as well. So it may not be the best thing for people trying to maximize muscle size, but may be a good thing during a fat-burning rotation. They say that for someone who wants to build muscle, cardio should be done later in the day (ie not on an empty stomach), preferable on a different day to weight lifting.
I would be interested to hear Maribeth's opinion on all this. I guess new theories come out all the time, and they often turn out to be wrong. Anyway, it has got me interesting in trying cardio first thing. I'm terrible at getting up extra early, though, so perhaps I'll give it a try on weekends...
Sharon.
