Running on Empty
Does doing cardiovascular exercise on an empty stomach really help you burn more fat?
by: Good Looking Kangaroo (w/ Good Looking Loser)
If you are familiar with our approach to Fat Loss or seen PhilTheBeard’s pictures where he’s dropped 60+ lbs in just over 3.5 months (amazing), you know that we stress doing cardiovascular activity (light jogging, NOT RUNNING) on an empty stomach- ideally first thing in the morning with a nice dose of Lipodrene and BCAA’s.
The concept is simple-
IF you exercise in a fasted state, your body will BURN FAT rather than glucose (carbohydrates/sugar), it’s preferred source for energy. Most people exercise after already consuming several meals that day. They will mainly burn off the food they ate rather than the body fat they are trying to shed. It takes them long, strenuous workouts to even get to the point of burning fat. A lot of wasted time and energy, if you ask me.
From my personal experience, I’ve found that exercising on an empty stomach- DRAMATICALLY burns more fat than exercising after eating a meal or three. To me, the difference is NIGHT and DAY.
When I was a personal trainer in Beverly Hills, I very seldom agreed to work with men and women that wanted to lose weight but somehow “couldn’t workout/do anything” in the morning.
I often throw around the claim that-
“you will burn 300% more fat on an empty stomach and get 3x faster results.”
Some guys (with credible physiques) still insist that it doesn’t make a difference what’s in or not in your stomach when you exercise with the goal of burning fat.
I absolutely disagree.
While it’s a no-brainer to me, given my experience (and trying to burn fat in a fed state) and the success of ALL my clients that followed my plan, I still felt it was still appropriate to examine my claim.
I woke up Good Looking Kangaroo who maintains a 24/7/365 6-six pack and has a Masters Degree in Clinical Nutrition to have him looking into the matter.
This is what our favorite Aussie Kangaroo found-
Heck everyone does, hence why people are searching for the quick fix.
But we all know too well that a weight loss quick fix doesn’t exist.
However, there are a couple of ways to get better results for your efforts.
This includes the use of a low carbohydrate diet (see GLL-get a life’s fat loss diet) and exercising in a fasted state. Training with limited carbohydrate availability can help stimulate adaptations in your body that facilitate energy production via fat oxidation – aka “fat burning”.
In this article, I’m going to run through how this physiological process works and give you a handful of scientific studies that back up the benefits of exercising in a fasted state. I’m also going to compare the effects of consistent training in the fasted state, vs. training in the fed state, on muscle metabolism and substrate selection during fasted exercise.
Be warned though, this is not a light read as some of the physiology is quite complex, however I’ll do my best to break down into easy to understand terms. If you can understand this, then you will be fast on your way to your dream physique.
The Physiology of Fasting
Fasting is the process of abstaining from consuming food and drinks for a set period of time.
During periods of fasting, your body’s metabolism shifts towards oxidizing a greater percentage of energy from your fat stores.
This process is known as “fat burning”.
Physiologically, when you break down (oxidize) fat molecules they are transported in the blood to your muscles to be used for energy. Once in your muscles, the fat molecules are transported into the mitochondrial membrane (a cell within the muscle) by an enzyme called carnitine palmitoyltransferase I (CPI). You may have heard of this product before, as it is quite commonly used as a weight loss supplement more commonly called carnitine. Carnitine transports the fat molecules into the mitochondrial membrane where they are broken down into energy and a by product called acetyl-coenzyme A. The acetyl-coenzyme A is then used to produce energy through a process known as the citric acid energy pathway. The end product of this pathway is energy… the energy you require to train hard. However the citric acid energy pathway only has a capacity to process so much acetyl-coenzyme A which leaves a surplus. This surplus is sent to the liver, where it is used to generate ketone bodies (acetoacetate and β-hydroxybutrate). The production of ketones is a sign that your body is breaking down a greater percentage of fat stores, then normally, for energy. This is the process of fat burning.
Ketones are often referred to as a dangerous state of health. However, those less informed people who promote this misinformation are confusing natural ketosis with the pathological state ketoacidosis. The latter is very different to ketosis, usually only observed in people who have been diagnosed with type 1 diabetes. In ketoacidosis, ketone levels are almost ten times higher. The concentration of ketones in a healthy person not in ketosis is approximately 0.1 mmol/L, which increases to about 0.3 mmol/L after an overnight fast. Fasting for prolonged periods can increase ketone concentrations to up to 10 mmol/L, however this is still not alarmingly high levels as ketoacidosis occurs somewhere around the 20 mmol/L concentration. It has been shown that following a very low carbohydrate diet (less than 20g of carbohydrates per day) for 4 weeks, only leads to an average ketone level of 3 mmol/L in healthy men. Ketosis due to either a low carbohydrate diet or exercising in a fasted state is safe as long your blood sugar levels are stable and your blood ketone levels are not at extremely high levels such as that observed during ketoacidosis.
Exercising in a Fasted State
Exercising in a fasted state is just one way you can put your body into a natural state of ketosis.
If your last meal was over 8-12 hours ago, and you perform physical activity, your body will have reduced liver and muscle glycogen stores available to supply carbohydrates for energy.
Being in this state, means you are more likely to burn stored body fat for energy which equates to weight loss! Exercising in a fasted state will help you shed more fat then exercising after a meal. Now let me be very clear, this is not based upon my opinion, this is based upon the science. Allow me to show you!
The first thing I want to show you is an analysis of five clinical studies that each compared the use of a low fat diet with the use of a very low carbohydrate ketogenic diet (VLCKD). These results will both astound you and just hit home how effective a very low carbohydrate diet is for weight loss. Figure 1.0 shows the weight lost by subjects in these studies over a 3-6 month period of following either the low fat diet or the very low carbohydrate ketogenic diet. On average, the subjects who followed the very low carbohydrate ketogenic diet lost on twice as much as those on the low fat diet.
Figure 1.0 – Comparison of weight loss studies using either a low fat diet or a very low carbohydrate ketogenic diet.1-5
Results like these simply highlight the significant advantage of using a low carbohydrate diet to lose weight then using a low fat diet. It’s a no brainer!
In a study published in 2010 in the Journal of Physiology, researchers put a small group of men on a high fat/calorie diet in an attempt to make them gain fat. The men were split up into three groups. One group did not perform any exercise at all during the six week study, one group did exercise after eating a meal and the third group did exercise prior to eating a meal in a fasted state. At the end of the six weeks, it was no surprise that the first group gained the most weight, after all they didn’t do any exercise. The second group however, also gained weight despite exercising. Most surprisingly the third group which performed the exercise in a fasted state, did not however gain weight. These guys also had better insulin sensitivity then the other two groups of guys. The researchers concluded that “fasted training is more potent than fed training to facilitate adaptations in muscle and to improve whole-body glucose tolerance and insulin sensitivity during hyper-caloric fat-rich diet”.
In another study published last year in the British Journal of Nutrition, researchers investigated the effects of exercise before or after meal ingestion on fat balance and postprandial metabolism in overweight men. They had a group of overweight men perform three trials for them. The first trial involved them not performing any exercise, the second trial involved them performing 60 mins of walking before a meal and the third trial involved them performing 60 mins of walking after a meal. The results showed that the group who performed the 60 mins of walking prior to eating (i.e. in a fasted state) had on average 20% greater fat loss then the group who ate and then exercised. Now 20% doesn’t sound like a great deal more of weight, however these results need to be put into perspective. The group of men only did 60 mins of walking and the intensity was quite light ~50% of their maximal effort. Performing moderate to high intensity exercise in a fasted state would provide even greater results then that demonstrated in this study.
It’s important that you learn how weight loss happens so you can develop a lifestyle that keeps unwanted fat away without spending 2 less-than-productive hours in the gym every day.
After all there is nothing more disheartening then focusing all your efforts into a diet or weight loss program, that later turns out to be nothing but a fad.
The GLL Fat Loss Diet is designed to maximize your body’s fat burning potential and deliver fast results. When combined with exercising in a fasted state, the fat burning potential is significantly increased.
Still- before you run out the door ready to run a marathon on an empty stomach there are a few precautions one must know.
Not everyone can safely and effectively perform exercise on an empty stomach. Some people report feeling dizziness, fatigue or simply cannot perform exercise at a decent level of intensity. If, unfortunately you fall into this group, you will most likely need to eat something (protein is the best option) prior to training. Try eating something that is low in carbohydrates and high in fat/protein to see if that helps.
Your morning workouts (with lipodrene and BCAAs) shouldn’t be that taxing. We only recommend ~30 minutes of light cardio and only lifting weights for about 15 minutes if you have the energy. Remember, this is a WEIGHT LOSS plan. Not a “be as big and strong as I can be” plan. My approach to that is TOTALLY different.
If you are able to tolerate exercising on empty, then you will be well on your way to shedding those pounds and revealing your dream physique.
It will happen much faster than if had already ate that day.
- Brehm BJ, Seeley RJ, Daniels SR, D’Alessio DA. A randomized trial comparing a very low carbohydrate diet and a calorie-restricted low fat diet on body weight and cardiovascular risk factors in healthy women. J Clin Endocrinol Metab 2003;88:1617-1623.
- Fost GD, Wyatt HR, Hill JO, et. al. A randomized trial of a low-carbohydrate diet for obesity. N Engl J Med 2003;348:2082-2090.
- Yancy ES Jr, Olsen MK, Guyton JR, Bakst RP, Westman EC. A low-carbohydrate, ketogenic diet versus a low-fat diet to treat obesity and hyperlipidemia: a randomised, controlled trial. Ann Intern Med 2004;140:769-777.
- Sondike SB, Copperman N, Jacobson MS. Effects of a low-carbohydrate diet on weight loss and cardiovascular risk factors in overweight adolescents. J PEdiatr 2003;142:253-258.
- Samaha FF, Iqbal N, Seshadri P, et l. A low-carbohydrate as compared with a low-fat diet in severe obesity. N Engl J Med 2003;348:2074-2081.