burning fat and cardio

Early in the morning before you eat, your levels of muscle and liver glycogen (stored carbohydrate) are low. If you eat dinner at 7 p.m and you eat breakfast at 7 a.m., that's 12 hours without food. During this 12-hour overnight fast, your levels of glycogen slowly decline to provide glucose for various bodily functions that go on even while you sleep. As a result, you wake up in the morning with depleted glycogen and lower blood sugar - the optimum environment for burning fat instead of carbohydrate. How much more fat you'll burn is uncertain, but some studies have suggested that up to 300% more fat is burned when cardio is done in a fasted, glycogen-depleted state. So how exactly does this work? Carbohydrate (glycogen) is your body's primary and preferred energy source. When your primary fuel source is in short supply, this forces your body to tap into its secondary or reserve energy source; body fat. If you do cardio immediately after eating a meal, you'll still burn fat, but you'll burn less of it because you'll be burning off the carbohydrates you ate first. You always burn a combination of fat and carbohydrate for fuel, but depending on when you exercise, you can burn a greater proportion of fat relative to carbohydrate. If doing cardio first thing in the morning is not an option for you, then the second best time to do it would be immediately after weight training. Lifting weights is anaerobic (carbohydrate-burning) by nature, and therefore depletes muscle glycogen. That's why a post lifting cardio session has a similar effect as morning cardio on an empty stomach. A lot of us disagree with when is the best time to do cardio, and if we should or shouldnt be in a fasted state. Ive read far too many books and articles that suggest the same thing....when going for JUST cardio, do so on an empty stomach. There may be new studies that show otherwise...time will tell. For now, the consensus is and has been for years....cardio in the morning and on an empty stomach is ideal. It works far too well for far too long to be considered bunk. This is just speaking of just cardio. For the people who weight lift, this dietary info isnt going to work for them. They would obviously lose muscle mass if they kept themselves fasted for too long in between meals. For those who are just going for some cardio...just for some fat burning...the info is solid.

But remember with early morning "lower blood sugar", that might put some people at risk of having low sugars if they workout before eating something. I usually do a small protein shake before the gym. I also do a small one right after my workout. Kathy

In my other posts I have mentioned this. I tend to eat a banana before an early morning workout. There is still not a lot of *sugars* or carbs in your system and you tent to go to the fat burn faster. You also need to read the entire postings from the last 2 weeks where I talk about the difference in nutrition needed for different types of workouts. You should be feeding a complex carb to your body before a workout, and protein after.

I love this! I have to agree about cardio in the morning. I'm 5 years out from surgery and started to see a slight gain and fall back for the last 9 months. I was working out in the evening or early afternoon and I just couldn't understand how I could do an hour of cardio and then resistance training and be gaining weight. I heard it all...."muscle weighs more then fat"....made me crazy. Well, due to my time constraints, I had to change my workout to 4:30 AM over a month ago. Low and behold....I started losing weight. I was 117 and now I'm down to 111. I've been maintaining with slight ups and downs for so long....and finally see weight loss again. I want to lose about 5 more lbs and that will put me right at the middle of a normal BMI. Besides....since I've started this....I have so much more energy throughout the day. I did have to make the effort to go to bed earlier, but now I'm totally use to it and feel better then ever.

thanks for the response. I have been putting in a lot of time and effort into this and hope it can help.

I do both, but that's really interesting about doing cardio AFTER weight training. I hadn't considered that. --BT

Ideally it should be done before AND after.

Thought I'd let you know that I do enjoy these informative articles you are posting every other day or so - THANKS ! -cbf

As far as I'm concerned, that information is wrong on many levels. The primary reason for this is the term for how exercise physiologists refer to how the body burns fat. "Fats burn in a carbohydrate flame." I don't mean to come off sounding mean or disrespectful in any way, I hope you see that. The information that you based your post on may have been old, and I totally understand. There are some websites or fat loss "professionals" that may encourage that type of exercise...but there is sound physiological evidence from scientific research that proves the argument wrong. For example, energy transfer, or how the body metabolizes carbs, fats, and protein for energy is the basis for my argument, as well as undergraduate and graduate work in exercise physiology. In order to explain that, some explanation should be done on energy transfer. The body does first burn carbs for energy, that fact is correct. But at the same time, "in metabolically active tissues, fatty acid breakdown depends on continual background levels of carbohydrate" breakdown. Fats also cannot produce glucose, the primary source of fuel for the body. But muscle can through the alanine-glucose cycle. Breaking down muscle energy is equal to the body eating itself in order to get energy. This breaking down of muscle also equals a substantial decrease in athletic performance. "Depleting carbohydrate reserves significantly increases protein catabolism during exercise." The perfect meal immediately before exercising should provide a source of carbs to sustain blood glucose and muscle metabolism, while minimizing a spike in insulin release (which is done after a rapidly absorbed high-glycemic carb is ingested, decreasing performance). Low glycemic carbs (such as apples, butter beans, fish sticks, and even peanuts [a good source of protein also]) in the 45-60 minutes before exercising allows a slower rate of glucose absorption and provide a better way for your body to burn carbs, optimizing fat mobilization and catabolism (burning fat) and spare liver and muscle glycogen reserves (the benefit of eating carbs). I recommend this site for learing more about glycemic load: http://lpi.oregonstate.edu/infocenter/foods/grains/gigl.html. The reason I recommend this site is because it is from a university, so we can be sure that their research is done correctly. Source: Exercise Physiology. Katch, Frank, Victor Katch, and William McArdle. Lippincott Williams and Wilkins, 2001.

So I am not exactly sure what you are trying to argue, or with whom. Apparently you have not read the other posts where I advocate a complex carb before exercise (for me 45-60 mins is a total waste & I need to eat closer to my workout). However, it has been proven time and time again that cardio on an empty stomach does burn glycogen and goes to the *fat* store. We are not talking about A "WORK-OUT" but a *fat* burn. I disagree wholehearted with some of the OLD information contain in your source. But that is the beauty of an exchange of ideas.