empty stomach cardio/fat burning zone

[james caan]

Ive always wondered which in fact is the best method for fat loss...cardio on an empty stomach, or cardio after a light meal. Most would say that cardio on an empty stomach works best, and they would give you an explanation of why that is the case. But even still, i always continued to wonder if all these people/trainers/authors/bros/etc were correct in their thinking. Also most cardio machines have the heart rate chart (many gyms have them as posters on walls) that provide us with the optimum fat burning zone. And to be very honest, even if unconsciously, i would always make sure to stay within that zone. Well i found these two videos by Will Brink that speak on both of these topics, based on current research studies. Might surprise some of you. Just wanted to add; I know this site is filled with BBing veterans that have been in the trenches for many years, if not decades. My posting of certain information and/or videos is in hopes of helping those members that have not been in the game that long, and are thirsty for as much knowledge as they can get. So please to all the vets on here, take no offense, or see this as attack on your methods of training, but as just another point of view, or potential for greater results. CJ

Fat Burning Zone Exposed - YouTube

Fasted Cardio: The Facts! - YouTube

btw: here's a short article written by Brad Schoenfeld, which explains which would be a better option in regards to cardio for fat loss.

Cardio Workouts: Is There A Best Time to Exercise?
By Brad Schoenfeld, CSCS, CPT

A popular fitness tenet is that cardio should be performed first thing in the morning on an empty stomach. The theory behind this belief is as follows: A prolonged absence of food brings about a reduction in circulating blood sugar, causing glycogen (stored carbohydrate) levels to fall. With a diminished availability of glycogen, your body tends to rely more on fat - rather than glucose - to fuel your workout. Under ideal conditions, there is an increased oxidation of fat during exercise - a fact that is supported by research.

The truth is, however, it's not always best to perform cardio as soon as you roll out of bed. Although the prospect of increasing fat oxidation sounds good on the surface, there are several misconceptions that need to be taken into account. For one, the human body is a very dynamic organism and continually adjusts its use of fat for fuel. Substrate utilization is governed by a host of factors (including enzyme levels, substrate availability, internal feedback loops, etc.) and these factors can literally change by the moment. Thus, simply looking at the amount of fat burned during exercise is shortsighted. Fat burning must be considered over the course of an entire day - not on an hour to hour basis - to get a meaningful perspective on its impact on body composition.

What's more, only about half of the fat utilized during aerobic exercise is mobilized from adipose tissue; the balance comes from fat stored intramuscularly (within muscle) . The important point here is that intramuscular fat has no bearing on aesthetic appearance; it's the subcutaneous fat stored in adipose tissue that influences body composition. Consequently, the actual fat-burning effects of the strategy are far less than otherwise thought.

In addition, studies have shown that eating before exercise actually increases caloric expenditure . This apparently is related to the thermic effect of food (TEF) . You see, every time you eat a mixed meal there is a corresponding increase in metabolic rate. When exercise is performed after the consumption of food, metabolism is heightened by about 20 percent over fasting levels. Better yet, these effects are maintained for up to three hours post-workout . And since burning more calories means burning more fat, eating before cardio can have thermogenic effects on exercise activity.

Perhaps more significantly, a pre-exercise meal allows you to exercise more intensely . In order to perform at a high level, your body needs a ready source of glycogen; deplete glycogen stores and your performance is bound to suffer. Compounding matters, not everyone functions well first thing in the morning. If you're more of a night bird, chances are that you'll sleepwalk through a morning workout. The net result is that fewer calories are burned during activity. Again, total caloric expenditure has a direct effect on fat oxidation, so these factors ultimately lead to a lower-quality, less-efficient exercise session.

In final analysis, simply increasing the percentage of calories burned from fat doesn't necessarily translate into an improved body composition. There isn't necessarily anything wrong with performing exercise after an overnight fast, but it isn't going to make a significant difference on your body's appearance, either. The best advice is to exercise when you are at your best; let your biorhythms determine when you should work out. If you are a morning person, go ahead and train early. But if you don't really get going until you've been awake for several hours, by all means train later in the day. All things considered, it really won't make much of a difference in your results.

 

[james caan]

I was trying to find the article that appeared in the strength and conditioning journal by Brad Schoenfeld (you have to buy the article online) but finally i found the entire article posted. I hope every one enjoys the read. CJ

Does Cardio After an Overnight Fast Maximise Fat Loss?

A common fat burning strategy employed by bodybuilders, athletes, and fitness enthusiasts is to perform cardiovascular exercise early in the morning on an empty stomach. This strategy was popularized by Bill Phillips in his book, ‘‘Body for Life’’ (23). According to Phillips, performing 20 minutes of intense aerobic exercise after an overnight fast has greater effects on fat loss than performing an entire hour of cardio in the postprandial state. The rationale for the theory is that low glycogen levels cause your body to shift energy utilization away from carbohydrates, thereby allowing greater mobilization of stored fat for fuel. However, although the prospect of reducing the body fat by training in a fasted state may sound enticing, science does not support its efficacy.

First and foremost, it is shortsighted to look solely at how much fat is burned during an exercise session. The human body is very dynamic and continually adjusts its use of fat for fuel. Substrate utilization is governed by a host of factors (i.e., hormonal secretions, enzyme activity, transcription factors, etc), and these factors can change by the moment (27). Thus, fat burning must be considered over the course of days—not on an hour-to-hour basis—to get a meaningful perspective on its impact on body composition (13). As a general rule, if you burn more carbohydrate during a workout, you inevitably burn more fat in the post- exercise period and vice versa.
It should be noted that high-intensity interval training (HIIT) has proven to be a superior method for maximizing fat loss compared with a moderate- intensity steady-state training (10,26,29). Interestingly, studies show that blood flow to adipose tissue diminishes at higher levels of intensity (24). This is believed to entrap free fatty acids within fat cells, impeding their ability to be oxidized while training. Yet, despite lower fat oxidation rates during exercise, fat loss is nevertheless greater over time in those who engage in HIIT versus training in the ‘‘fat burning zone’’ (29), providing further evidence that 24-hour energy balance is the most important determinant in reducing body fat.

The concept of performing cardiovascular exercise on an empty stomach to enhance fat loss is flawed even when examining its impact on the amount of fat burned in the exercise session alone. True, multiple studies show that consumption of carbohydrate before low- intensity aerobic exercise (up to approximately 60% V_o2max) in untrained subjects reduces the entry of long-chain fatty acids in the mitochondria, thereby blunting fat oxidation (1,14,18,28). This is attributed to an insulin-mediated attenuation of adipose tissue lipolysis, an increased glycolytic flux, and a decreased expression of genes involved in fatty acid transport and oxidation (3,6,15). However, both training status and aerobic exercise intensity have been shown to mitigate the effects of a pre-exercise meal on fat oxidation (4,5,24). Recent research has shed light on the complexities of the subject.

Horowitz et al. (14) studied the fat burning response of 6 moderately trained individuals in a fed versus fasted state to different training intensities. Subjects cycled for 2 hours at varying intensities on 4 separate occasions. During 2 of the trials, they consumed a high-glycemic carbohydrate meal at 30, 60, and 90 minutes of training, once at a low intensity (25% peak oxygen consumption) and once at a moderate intensity (68% peak oxygen consumption). During the other 2 trials, subjects were kept fasted for 12–14 hours before exercise and for the duration of training. Results in the low-intensity trials showed that although lipolysis was suppressed by 22% in the fed state compared with the fasted state, fat oxidation remained similar between groups until 80–90 minutes of cycling. Only after this point was a greater fat oxidation rate observed in fasted subjects. Conversely, during moderate-intensity cycling, fat oxidation was not different between trials at any time—this is despite a 20–25% reduction in lipolysis and plasma Free fatty acid concentration.

More recently, Febbraio et al. (9) evaluated the effect of pre-exercise and during exercise carbohydrate consumption on fat oxidation. Using a crossover design, 7 endurance- trained subjects cycled for 120 minutes at approximately 63% of peak power output, followed by a ‘‘performance cycle’’ where subjects expended 7 kJ/(kg body weight) by pedaling as fast as possible. Trials were conducted on 4 separate occasions, with subjects given (a) a placebo before and during training, (b) a placebo 30 minutes before training and then a carbohydrate beverage every 15 minutes throughout exercise, (c) a carbohydrate beverage 30 minutes before training and then a placebo during exercise, or (d) a carbohydrate beverage both before and every 15 minutes during exercise. The study was carried out in a double- blind fashion with trials performed in random order. Consistent with previous research, results showed no evidence of impaired fat oxidation associated with consumption of carbohydrate either before or during exercise.

Taken together, these studies show that during moderate-to-high intensity cardiovascular exercise in a fasted state—and for endurance-trained individuals regardless of training intensity— significantly more fat is broken down than that the body can use for fuel. Free fatty acids that are not oxidized ultimately become re-esterified in adipose tissue, nullifying any lipolytic benefits afforded by pre-exercise fasting.

It should also be noted that consumption of food before training increases the thermic effect of exercise. Lee et al. (19) compared the lipolytic effects of an exercise bout in either a fasted state or after consumption of a glucose/milk (GM) beverage. In a crossover design, 4 experimental conditions were studied: low-intensity long duration exercise with GM, low-intensity long duration exercise without GM, high- intensity short duration exercise with GM, and high-intensity short duration exercise without GM. Subjects were 10 male college students who performed all 4 exercise bouts in random order on the same day. Results showed that ingestion of the GM beverage resulted in a significantly greater excess postexercise oxygen consumption compared with exercise performed in a fasted state in both high- and low- intensity bouts. Other studies have produced similar findings, indicating a clear thermogenic advantage associated with pre-exercise food intake (7,11).

The location of adipose tissue mobilized during training must also be taken into account here. During low-to- moderate intensity training performed at a steady state, the contribution of fat as a fuel source equates to approxi- mately 40–60% of total energy expen- diture (30). However, in untrained subjects, only about 50–70% of this fat is derived from plasma Free fatty acids; the balance comes from intra- muscular triglycerides (IMTG) (30).
IMTG are stored as lipid droplets in the sarcoplasm near the mitochondria (2), with the potential to provide approximately two-thirds the available energy of muscle glycogen (32). Similar to muscle glycogen, IMTG can only be oxidized locally within the muscle. It is estimated that IMTG stores are approximately 3 times greater in type I versus type II muscle fibers (8,21,31), and lipolysis of these stores are max- imally stimulated when exercising at 65%V_o2max(24).

The body increases IMTG stores with consistent endurance training, which results in a greater IMTG utilization for more experienced trainees (12,16,22,31). It is estimated that nonplasma fatty acid utilization during endurance exercise is approximately twice that for trained versus untrained individuals (24,32). Hurley et al. (17) reported that the contribution of IMTG stores in trained individuals equated to approximately 80% of the total body fat utilization during 120 minutes of moderate- intensity endurance training.
The important point here is that IMTG stores have no bearing on health and/or appearance; it is the subcutaneous fat stored in adipose tissue that influences body composition. Consequently, the actual fat burning effects of any fitness strategy intended to increase fat oxida- tion must be taken in the context of the specific adipose deposits providing energy during exercise.

Another factor that must be considered when training in a fasted state is its impact on proteolysis. Lemon and Mullin (20) found that nitrogen losses were more than doubled when training while glycogen depleted compared with glycogen loaded. This resulted in a protein loss estimated at 10.4% of the total caloric cost of exercise after 1hourofcyclingat61%V_o2max.This would suggest that performing cardio- vascular exercise while fasting might not be advisable for those seeking to maximize muscle mass.

Finally, the effect of fasting on energy levels during exercise ultimately has an effect on fat burning. Training early in the morning on an empty stomach makes it very difficult for an individual to train at even a moderate level of intensity. Attempting to engage in a HIIT style routine in a hypoglycemic state almost certainly will impair performance (33). Studies show that a pre-exercise meal allows an individual to train more intensely compared with exercise while fasting (25). The net result is that a greater number of calories are burned both during and after physicalactivity,heightening fat loss.

In conclusion, the literature does not support the efficacy of training early in the morning on an empty stomach as a tactic to reduce body fat. At best, the net effect on fat loss associated with such an approach will be no better than training after meal consumption, and quite possibly, it would produce inferior results. Moreover, given that training with depleted glycogen levels has been shown to increase proteolysis, the strategy has potential detrimental effects for those concerned with muscle strength and hypertrophy.

 

[thebigguy84]

Well I cannot read all that in RED but Fasted Cardio is the best to jumpstart your metabolism. Morning cardio on a empty stomach with a little black coffee and your bcaa will burn fat like no other I know this method too well.

 

[hotrod]

:yeahthat:
Look if your looking for some perfect scenario, well you and everybody else will be looking for a long time. Will Brink is correct as most times he is,are you going to burn 3 times as much fat by doing cardio in the morning ,no, but as stated as above it is a great jump starter you get your body using fat more efficiently. And over time it makes a big difference, especially if your not of great genetic disposition. I being one, along with a lot of my clients. Some people can train and do cardio right after eating and still lose great amount of fat ,Makes me sick,but it is just a fact. How I, or any other trainer worth there weight, train people depends a lot on that individual. Some people can only do moderate amounts of cardio because they will lose too much muscle, and compound the problem in the long run. That is why taking anti catobolics have become such a big deal in fat loss, it allows you to work harder eat less and lose fat much quicker,W/O as much muscle loss(the big key). So I whole heartily agree with cardio in fasted state, just depends on the person as to how much and what intensity and what there taking to help preserve muscle in the process.

 

[SugarFree]

I think either way would see progress but as for optimal results when performing cardio your still better off on an empty stomach. When you first start performing an exercise whether thats resistance training or cardio your body is going to burn the glyocogen in your body. Depletion will vary depending on the intesisty of your body but I believe one study points to that its not till after the first 20-30 minutes of cardio before your body reaches the point that it starts burning fat for fuel. This may be a lot less for someone that may be low carbing in the first place but to me while dieting it simply suggests that I either start on an empty stomach or start by lifting first and use that extra glyocogen towards pushing weight.

 

[james caan]

from all the studies done, at least newer studies, it shows that cardio done on a empty stomach (fasted state) is not only less effective for actual body composition changes, but can also be catabolic. i know we all have heard this for years (empty stomach is best), so it may be difficult to change things up, but if all this information is accurate than i think we are doing our body's a disservice by not at least trying it for ourselves. and as far as fat usage, as Will Brink stated in the video...fat usage (body fat percentage) isn't what is most important for body composition changes, but calories (total calories) usage. so if the argument is that by doing cardio in a fasted state helps you get into a fat burning "zone" faster, and what Will Brink (and the studies) is/are saying indeed true, then again cardio on an empty stomach would really hold no actual benefit. not trying to argue with any one, i just wanted to start a healthy discussion on this topic...CJ

**In conclusion, the literature does not support the efficacy of training early in the morning on an empty stomach as a tactic to reduce body fat. At best, the net effect on fat loss associated with such an approach will be no better than training after meal consumption, and quite possibly, it would produce inferior results. Moreover, given that training with depleted glycogen levels has been shown to increase proteolysis, the strategy has potential detrimental effects for those concerned with muscle strength and hypertrophy.**

 

[james caan]

bump, looking for more opinions, and views on the article. CJ

 

[SOUR DIESEL]

Well I cannot read all that in RED but Fasted Cardio is the best to jumpstart your metabolism. Morning cardio on a empty stomach with a little black coffee and your bcaa will burn fat like no other I know this method too well.

+1 ..it works no question

 

[Soulstealer]

I do a protein/fat meal before morning cardio I feel it helps me retain muscle

50g protein from liquid egg whites
3-4g of fat from oliveoil (extra virgin)
4g of fat from fish oil

IMO the two best times to do cardio are when you wake up before you have eaten any carbs... and at night... hours after your last carb meal and before you eat your last meal of the day...

 

[Crowler]

from all the studies done, at least newer studies, it shows that cardio done on a empty stomach (fasted state) is not only less effective for actual body composition changes, but can also be catabolic. i know we all have heard this for years (empty stomach is best), so it may be difficult to change things up, but if all this information is accurate than i think we are doing our body's a disservice by not at least trying it for ourselves. and as far as fat usage, as Will Brink stated in the video...fat usage (body fat percentage) isn't what is most important for body composition changes, but calories (total calories) usage. so if the argument is that by doing cardio in a fasted state helps you get into a fat burning "zone" faster, and what Will Brink (and the studies) is/are saying indeed true, then again cardio on an empty stomach would really hold no actual benefit. not trying to argue with any one, i just wanted to start a healthy discussion on this topic...CJ

**In conclusion, the literature does not support the efficacy of training early in the morning on an empty stomach as a tactic to reduce body fat. At best, the net effect on fat loss associated with such an approach will be no better than training after meal consumption, and quite possibly, it would produce inferior results. Moreover, given that training with depleted glycogen levels has been shown to increase proteolysis, the strategy has potential detrimental effects for those concerned with muscle strength and hypertrophy.**

They didn't use hgh nor AAS so the study is useless if you use either of these.

 

[SugarFree]

They didn't use hgh nor AAS so the study is useless if you use either of these.

haaaa, got a laugh from that one.