Phys Ed: The Benefits of Exercising Before Breakfast
By GRETCHEN REYNOLDS
The holiday season brings many joys and, unfortunately, many countervailing dietary pitfalls. Even the fittest and most disciplined of us can succumb, indulging in more fat and calories than at any other time of the year. The health consequences, if the behavior is unchecked, can be swift and worrying. A recent study by scientists in Australia found that after only three days, an extremely high-fat, high-calorie diet can lead to increased blood sugar and insulin resistance, potentially increasing the risk for Type 2 diabetes. Waistlines also can expand at this time of year, prompting self-recrimination and unrealistic New Year’s resolutions.
But a new study published in The Journal of Physiology suggests a more reliable and far simpler response. Run or bicycle before breakfast. Exercising in the morning, before eating, the study results show, seems to significantly lessen the ill effects of holiday Bacchanalias.
For the study, researchers in Belgium recruited 28 healthy, active young men and began stuffing them with a truly lousy diet, composed of 50 percent fat and 30 percent more calories, overall, than the men had been consuming. Some of the men agreed not to exercise during the experiment. The rest were assigned to one of two exercise groups. The groups’ regimens were identical and exhausting. The men worked out four times a week in the mornings, running and cycling at a strenuous intensity. Two of the sessions lasted 90 minutes, the others, an hour. All of the workouts were supervised, so the energy expenditure of the two groups was identical.
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Their early-morning routines, however, were not. One of the groups ate a hefty, carbohydrate-rich breakfast before exercising and continued to ingest carbohydrates, in the form of something like a sports drink, throughout their workouts. The second group worked out without eating first and drank only water during the training. They made up for their abstinence with breakfast later that morning, comparable in calories to the other group’s trencherman portions.
The experiment lasted for six weeks. At the end, the nonexercising group was, to no one’s surprise, super-sized, having packed on an average of more than six pounds. They had also developed insulin resistance — their muscles were no longer responding well to insulin and weren’t pulling sugar (or, more technically, glucose) out of the bloodstream efficiently — and they had begun storing extra fat within and between their muscle cells. Both insulin resistance and fat-marbled muscles are metabolically unhealthy conditions that can be precursors of diabetes.
The men who ate breakfast before exercising gained weight, too, although only about half as much as the control group. Like those sedentary big eaters, however, they had become more insulin-resistant and were storing a greater amount of fat in their muscles.
Only the group that exercised before breakfast gained almost no weight and showed no signs of insulin resistance. They also burned the fat they were taking in more efficiently. “Our current data,” the study’s authors wrote, “indicate that exercise training in the fasted state is more effective than exercise in the carbohydrate-fed state to stimulate glucose tolerance despite a hypercaloric high-fat diet.”
Just how exercising before breakfast blunts the deleterious effects of overindulging is not completely understood, although this study points toward several intriguing explanations. For one, as has been known for some time, exercising in a fasted state (usually possible only before breakfast), coaxes the body to burn a greater percentage of fat for fuel during vigorous exercise, instead of relying primarily on carbohydrates. When you burn fat, you obviously don’t store it in your muscles. In “our study, only the fasted group demonstrated beneficial metabolic adaptations, which eventually may enhance oxidative fatty acid turnover,” said Peter Hespel, Ph.D., a professor in the Research Center for Exercise and Health at Catholic University Leuven in Belgium and senior author of the study.
At the same time, the fasting group showed increased levels of a muscle protein that “is responsible for insulin-stimulated glucose transport in muscle and thus plays a pivotal role in regulation of insulin sensitivity,” Dr Hespel said.
In other words, working out before breakfast directly combated the two most detrimental effects of eating a high-fat, high-calorie diet. It also helped the men avoid gaining weight.
There are caveats, of course. Exercising on an empty stomach is unlikely to improve your performance during that workout. Carbohydrates are easier for working muscles to access and burn for energy than fat, which is why athletes typically eat a high-carbohydrate diet. The researchers also don’t know whether the same benefits will accrue if you exercise at a more leisurely pace and for less time than in this study, although, according to Leonie Heilbronn, Ph.D., a professor at the University of Adelaide in Australia, who has extensively studied the effects of high-fat diets and wrote a commentary about the Belgian study, “I would predict low intensity is better than nothing.”
So, unpleasant as the prospect may be, set your alarm after the next Christmas party to wake you early enough that you can run before sitting down to breakfast. “I would recommend this,” Dr. Heilbronn concluded, “as a way of combating Christmas” and those insidiously delectable cookies.
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1. December 15, 2010 1:11 am Link
The weight loss benefits of “exercising in a fasted state” have also been noted elsewhere in recent years.
Sometimes it’s referred to as “bonk training”. For example, from the September 2002 Bicycling magazine:
HOW TO BONK TRAIN1. Upon waking, drink 2-3 cups of coffee, up to 45 minutes before cycling. Don’t eat.2. Ride at endurance pace- 60-70% of your max heart rate, or a casual pace that doesn’t make you pant when you talk.3. Keep it up for 20-90 minutes.4. You can do this on consecutive days, but mix in at least one normal breakfast per week.5. Eat your typical breakfast as soon as the ride ends.6 . Watch the blubber ignite!!
If you’re _already_ at a good weight, “bonk training” wouldn’t be desireable for a serious amateur athlete … you generally can’t do an intense quality workout, for the purpose of building aerobic endurance, on an empty stomach.— Kirth Gersen
2. December 15, 2010 1:14 am Link
As always, a study conducted with only male participants. I wouldn’t be surprised if women’s bodies behaved very differently.— S
3. December 15, 2010 1:59 am Link
What lessons am I, a 50-something woman, supposed to take from a study that enrolled 28 healthy young men?— JenofNJ
4. December 15, 2010 2:45 am Link
I wonder if coffee would substitute for water – at least some of it. Probably not so lucky. I’m guessing 30 min might be an ol’ foggies limit anyway. Mine is 2 minutes! then I gotta rest … or die,— Chamae
5. December 15, 2010 2:55 am Link
And then, of course, there is the emotional factor.
For me at least, a pre-breakfast workout has me feeling great all day, whereas a post breakfast workout high only lasts a couple of hours.— Brian
6. December 15, 2010 3:45 am Link
But I won’t give up my morning coffee before doing my morning training.http://www.lifestyle-after50.com/coffee.html— 50PlusSam
7. December 15, 2010 5:23 am Link
**”I would recommend this,” Dr. Heilbronn concluded, “as a ways of combating Christmas…”**Lock up the presents! Guard the Roast Beast! All you Who’s down in Whoville (or at least in Adelaide environs) GRINCH ALERT!Presume the Scrooge-y Dr. H also offers freelance credit advice on coping with bulging credit card waistlines, recipes for eggnog made of fat-free, sugarless eggnog and suggests coal for all who have been either naughty OR nice.“Combating Christmas”… To the ramparts! Or at least to the track before you eat a morsel all you BAD gluttonous children.Wait! Adelaide is in Australia where Christmas arrives in the middle of summer… aka Santa in a Speedo sipping a 40 oz. can of Fosters… never mind.— St. Nickedoff
8. December 15, 2010 6:11 am Link
Interesting study. I wish the weight loss industry would pay attention. As someone who exercises primarily to keep the pounds off and not to compete in marathons, I have always exercised before breakfast with only water and have never understood why so many advice sources claim it is this awful thing to exercise on an empty stomach and suggest these high carb drinks to casual exercisers to supposedly improve our workouts. If you’re just trying to lose weight or stay in shape, it makes absolutely no sense to eat a 200 calorie energy bar before you get on the exercise bike and then drink 100 calories of gatorade during a workout in which you’ll only burn about 200-300 calories in the first place.— Kdd
9. December 15, 2010 6:33 am Link
The fasting group lost weight because they had to destroy their muscles to find energy.Not a good idea for permanent weight loss.Excellent experiment but very bad results interpretation.Dr Salomon Jakubowicz— Salomon Jakubowicz
10. December 15, 2010 6:45 am Link
This is a fascinating article! Can’t wait to read the whole thing.
Here’s what I’m thinking–if you eat late–and a lot of “party food” you probably aren’t going to be hungry first thing in the morning. So just go for exercising on an empty stomach.
Under normal circumstances–grab a light-hold-you-over breakfast before exercising. Eat more afterward.
Glad someone figured this out. Quite shocking how quickly diet adversely affects one’s body!— The Healthy L ibrarian
11. December 15, 2010 7:10 am Link
The benefits of exercising before breakfast are….. feeling nauseated and dizzy. No thanks!— S
12. December 15, 2010 7:14 am Link
The holidays can be such a joyful time of year, but all the excess calories, alcohol, stress, and increased demand on our bodies can cause us to suffer unexpected holiday effects, like insulin resistance and also heart attack. See ‘Avoiding Holiday Heart Attacks’ on my blog at http://www.ladywiththepants.com and find some simple ways to protect yourself and your family this holiday season.— Theresa Ayala
13. December 15, 2010 7:29 am Link
As a long time runner I have found that when I run before breakfast I actually feel stronger during my run. After a glass of water I am out the door, but it does take a bit of getting used to.— Tony
14. December 15, 2010 7:52 am Link
I have lost 10 pounds since May with eliminating breakfast and eating standard healthy lunches and dinners of high fiber, low sodium. I had read of similar study last spring.— gallega
15. December 15, 2010 8:06 am Link
I usually can’t stomach food until after 9am anyway, so working out on a glass of OJ, some coffee and maybe a banana first thing in the morning is normal for me. Good to know that aside from starting my day well oxygenated and warmed up might also benefit me in this other way.— Morgans
16. December 15, 2010 8:24 am Link
Does anyone know how researchers determine that undigested fats, as opposed to carbs, are being burned during exercise?
For years I’ve read claims about ‘the fat-burning zone’ — in which a higher percentage of fat is burned during cardio, but I’ve never seen any published description of the methodology, and have no idea whether it is fact or health myth.
How does one know whether the burned fat came from stored body fat, or simply undigested fats from food?— Sequel
17. December 15, 2010 8:35 am Link
The other benefit of committing to exercising before breakfast is that a person is more likely to do it. If I postpone my run until the middle or end of the day, I am likely to come up with some excuse to skip it. I try to roll out of bed and head out the door before I can think of a reason not to, and that has worked for years.— Kris
18. December 15, 2010 8:38 am Link
I would like to see a study that is comprised of women. Some researchers are finally starting to understand that studies done on young relatively healthy males do not truly apply to women.— Lisa
19. December 15, 2010 8:44 am Link
Wow! These findings really point out how our bodies behave when it comes to food. And yet, for some cultural reason our breakfasts are usually one of the worst meals of the day loaded with fats and sugars. Pancakes and eggs, anyone? The institution of breakfast is leading us into obesity and I for one cannot understand WHY anyone living at home with an adequate kitchen has to go OUT for breakfast!! Add the expense and you have a formula for disaster. Now, consider the millions that leave home and MUST STOP at a fast food restaurant for breakfast on the run, or drive, to work. This study confirms the hazards of a high calorie/fat breakfast along with a sedentary job. I have a feeling that the TV show The Biggest Loser” will run for decades and will never run of candidates.— Rayman
20. December 15, 2010 8:51 am Link
How can we reach conclusions so firmly based on research conducted only 28 participants and also gain such a widespread publicity ?http://www.vegetarian-zone.com— Vegetarian
21. December 15, 2010 8:54 am Link
I always exercise before breakfast – I’m so habituated to it that I just wake up and jump on the elliptical or go out running or walking without even thinking about it. The psychological benefit is huge – you’re halfway through your work-out before you’re even awake! And you’re done for the day, which is a great feeling. So even if it didn’t have the physical effects described above, I’d still recommend it!— Nancy
22. December 15, 2010 8:56 am Link
Vigorous exercise BEFORE meals (if not an empty stomach) seems just common sense — unless you like the taste of vomit in your mouth. [And who DOESN'T?]I’m sure glad somebody got those wacky Belgians to go all human guinea pig for a project to discover something perfectly obvious.Imagine the joy of the “‘twerps” either pigging out in the AM and then twiddling their Elvish thumbs — OR then tearing about for 90 minutes of soul-crushing exercise. I hope they were well remunerated, or at least given a “fancy” sample of delicious Belgian chocolates for their efforts.Of course running, weight lifting, swimming or whatever morning workout you choose done on an empty stomach. (Uh, going without “breakfast” isn’t much of an option for those who like to work out late.)There is all the business about carbo-loading for endurance fuel, but if you are trying to cut down on calories to lose a few lbs through exercise it doesn’t make much sense to guzzle hundreds of calories in sugary sports drinks while you are shedding only a few dozen calories with a brisk morning run. Thirsty? I have one word for you: water.Keep in mind that I am NOT what you call a “breakfast person” unless I find a Denny’s open off the freeway in Riverside while I’m driving through on vacation. My first meal is normally around 2-ish. Yeah, I know breakfast is the most important meal of the blah-blah-blah. Okay, then I have my “breakfast” about 2. Now are you happy?Here’s a concept that even a Belgian waffle can comprehend: Work out vigorously, then eat sensibly.— Ringdem Belgians
23. December 15, 2010 9:07 am Link
I wish I hadn’t read this one … I typically do exercise in the morning on an empty stomach – that’s the most time efficient for me and also generally when I feel best. However, I injured my ankle and can’t do anything but some laying down Pilates / sit ups right now … so I just further depressed myself and am missing my morning workouts even MORE now …The message of importance of exercise always bombards me – I LOVE to exercise and can always find a way to work it into schedule (even with a 1 yr old and a full time job), but, alas, injuries rather than desire often keep me away from it.— kfb
24. December 15, 2010 9:13 am Link
To be clear, I just read the study and the “high-fat diet” was also a high-carb diet – 50% of the calories came from fat, 40% of the calories came from carb and 10% came from protein. Of the four diets that the participants were given (3000, 3500, 4000, 4500 calories), the lowest calorie diet (3000) alone had 167 grams of fat and 300 grams of carb, an extraordinary amount of both!
Just wanted to clarify that the effect was probably not due to the fat alone and that 300 grams of carbohydrate is just, wow, an incredible amount that will surely make anyone’s blood glucose skyrocket.
Is it just me, or is the study also vague about what type of breakfast the fasting group received? Did they receive the high-carb breakfast as well?— FoodieRD
25. December 15, 2010 9:18 am Link
The results of this new study are astounding. It’s sure to unnerve the Oprah and Dr. Phil watching masses.
“But a new study published in The Journal of Physiology suggests a more reliable and far simpler response. Run or bicycle before breakfast.”
“…the non-exercising group was, to no one’s surprise, super-sized, having packed on an average of more than six pounds.”
“Only the group that exercised before breakfast gained almost no weight”
“Our current data,” the study’s authors wrote, “indicate that exercise training in the fasted state is more effective than exercise in the carbohydrate-fed state”
…“exercising in a fasted state (usually possible only before breakfast), coaxes the body to burn a greater percentage of fat for fuel during vigorous exercise, instead of relying primarily on carbohydrates.”
“In other words, working out before breakfast directly combated the two most detrimental effects of eating a high-fat, high-calorie diet. It also helped the men avoid gaining weight.”
Who would have ever even entertained such radical and ground-breaking theories. Maybe a blaspheming maverick like Jack LaLanne who was practically born in the 19th century? (“At the age of 96, LaLanne continues to work out every morning for two hours. He spends 1½ hours in the weight room and half an hour swimming or walking.”)
Good old, old Jack. But…what did he know.
I’ve hear that a new study is underway in one of those radical universities in California. They’re theorizing that the earth isn’t flat. Imagine that.— RC
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