Working Out on an Empty Stomach

Does working out on an empty stomach help you lose weight faster?  This should be a fairly simple question to answer.  Of course, this being a fitness question means that the answer is anything but simple.

With so many agendas and experts, one could easily get whiplash listening to – or reading – one guru to the next.

I decided to take a look at this topic after reading an interesting article – Confusing Fitness Advice, Decoded – that was featured at  It listed 7 of the top fitness questions, of which number two was:

2. Should You Work Out On An Empty Stomach?

The Confusion – We know that food fuels us. But if you’re looking to lose weight, some people—possibly those who read the 1999 bestseller Body for Life—believe exercising with a growling tummy may help burn fat faster. “The rationale behind this theory is that low glycogen levels cause your body to shift energy utilization away from carbohydrates toward fat,” says Keri Peterson, MD, a medical contributor to HealthiNation.

The Reality – This theory holds no weight in the scientific community. “Results of studies show that with low-intensity to moderate exercise, fat burning remained the same for up to 90 minutes in both fasting and non-fasting subjects,” says Dr. Peterson. Need further proof? Working out with or without food in your tummy won’t affect the amount of fat you torch—but not eating before working out may cause muscle loss if you do it regularly, according to the February 2011 issue of Strength and Conditioning Journal.

The Bottom Line  – When your body is famished, it kicks into survival mode and starts using muscle—like those abs you’ve been working on—as a source of protein. Do your bikini body a favor and make sure you have a light meal or sports drink to raise your blood sugar before exercise.

Read more:

Likewise, Anahad O’Connor came to the same conclusion – “Exercising on an empty stomach does not help burn more fat” – in her short analysis of the same study; her conclusion you can read here:

Really? The Claim: Exercising on an Empty Stomach Burns More Fat

The study that both article reference is here:

Does Cardio After an Overnight Fast Maximize Fat Loss?

I’m no genius – clearly but I do have some issues here.  First, I’d hardly come to iron clad conclusions based on one study.  Because, to coin and mangled a phrase – studies are a dime a dozen.

Case in point, this study as discussed by Martin Berkhan at this site – Leangains – titled “Fasted Training Boosts Muscle Growth?

A recent study shows fasted training affects the post-workout anabolic response to weight training more favorably than fed-state training.

This study is very interesting to say the least, since it lends scientific support to explain the beneficial effects from both fasted-training and Leangains-style intermittent fasting. Let me give you the lowdown on this study in layman’s terms.

Read more here…

The study in question can also be accessed through this link or through the link in Martin Berkhan’s article.

Increased p70s6k phosphorylation during intake of a protein–carbohydrate drink following resistance exercise in the fasted state

So you can always find studies to support a position.

That said, let’s or let me take whack a couple of the statements from the Prevention article:

“When your body is famished, it kicks into survival mode and starts using muscle—like those abs you’ve been working on—as a source of protein.”

Bold statement.

The issue for me is at what point does the body decide that it is famished and start cannabalizing the muscles.  According to this, that point is somwhere roughly betweem 8 to 12 hours after your last meal.  Supper at 6pm and you work out around 5 or 6 am the next morning.


So about 12 hours or so, you body becomes famished and you go into starvation mode?


And if you do it regularly – the cannabalization turns to muscle loss.


Someone forgot to tell the Army.

I spent 9 years doing early morning PT.  By 6am, we’d have generally run 3 miles and had 30 minutes of calisthenics – long before breakfast.

So…how many wasted, muscle-cannabalized GI have you seen?

Literally, millions and millions of young men and women deal with early morning workouts on an empty stomach and seem to be in great shape.

Jeff Anderson in his Combat the Fat Weight Program wrote this in his EBook of same name:

Military PT Strategy #3: Train On An Empty Stomach

In the military, we exercised first thing in the morning before we did ANYTHING else…and that INCLUDES eating!

You see, since you’ve fasted overnight, your body has less stored up BLOOD SUGAR and less MUSCLE GLYCOGEN so when you start to exercise, you don’t have as much of these fuel sources and can tap into your BODY FAT for fuel a bit quicker.

The one drawback to this method was that while it works GREAT for LOW-INTENSITY training when you already have body fat in your crosshairs…

Unfortunately, there’s no link to that EBook.  I copied this little sliver from the EBook I bought from Jeff for 47 bucks.  I think copyright laws would probably bite me if I copied/pasted more.

What The Heck They Thinking – Exercising on an Empty Stomach

That said, Jeff’s EBook/Program is as comprehensive a Weight Loss program as you will find.  It is holistics in its approach and as “Combat..” might imply, Jeff used a lot of his military background/experience to formulate this approach.  You can research his site here.

Back to starvation…

Rusty Moore of Fitness Black Book wrote “Starvation mode is a term that gets thrown around loosely. Many people believe that too little protein or too few of calories in a day will cause loss of muscle mass…it is extremely difficult to go into starvation mode until you get down to 5% body fat(10% for women)…”

Part of Rusty’s conclusion came from the extensive works of Karl E. Friedl, Army Operational Medicine Research Program, U.S. Army Medical Research and Materiel Command.  One of the most interesting studies that Karl Friedl published was:

Military Strategies for Sustainment of Nutrition and Immune Function in the Field

This Ebook is a tremendous study on macro-nutrients and micro-nutrients on human body.  Good reading!

In any event, within the focus of weight loss, fat burning, low-intensity exercises – I’m of the mind that exercising on an empty stomach is a good idea and can work.

What do you think?

I think ultimately what time you choose to work out at should be what works for you and your lifestyle.  Once you have committed to an active lifestyle that includes  3 to 4 workouts a week – give or take – and a healthy diet, including getting a plenty of rest; you’re good.  You are good!

Like I stated earlier, I’ve spent many years getting up at “o’dark thirty” to a 3 mile run and I was okay – like millions of others.

Having said that, I’ve worked out on an empty stomach and nearly collapsed from exhaustion, too. But that has only happened when I’ve gone all day without eating and then tried to work out.  I think that’s too much stress.

There’s a huge differen in my mind – such as it is – between getting up at 6am and going all day with basically nothing to eat.  Then trying to get in a 3 to 4 mile run at 5 or 6pm.

Versus, getting up at 6am and going for a 3 mile run.  Again, based on no scientific study, I’m assuming the body has been in a kinda of hibernation mode where not too calories are consumed and the fuel tank is still in good shape.  This, of course, assumes that you were eating a good, healthy diet all day the previous day.

Does this makes sense?

I’m not necessarily advocating working out on an empty stomach.  Rather, I’m trying to throw some commonsense that this issue.

If you want to work out on an empty stomach and you think it will be beneficial to you, then it will be and it can work for you.

The only caution is from my own experience where an empty stomach has to be at the beginning of the day – not at the end of the day.

Other than that, choose the timeframe that works for you and tune out all the experts.

Good Luck.



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