Is Exercise a Metabolism Booster? Maybe Not.
By: Jen Mueller,
SparkPeople Blogger
7/10/2009 10:10 AM
: 125 comments
: 13,397 Views
Does regular exercise help you burn more fat, even hours after your workout is over? Although a metabolism boost is touted as one of the benefits of physical activity, a new report says that exercisers won't burn more fat after a workout compared to days when they don't exercise.
The report, published in the journal Exercise and Sport Science Reviews, studied people who did a moderate-intensity workout, high-intensity workout or no workout at all (on separate days). They also compared people of different age groups and those who were competitive athletes, versus sedentary obese and sedentary lean individuals. Throughout all of these comparisons, one result was consistent: There seemed to be no difference in how much fat participants burned 24 hours after a workout, compared to days when they didn't exercise.
This study looked at workouts that were under one hour in length, so researchers can't be sure that longer, more intense workouts would produce the same results. The study also discusses the popular belief that weight training dramatically increases metabolism. A pound of muscle does burn more calories at rest than a pound of fat. But most people don't put on enough muscle to make enough of a difference. For instance, if someone gained 4-5 pounds of muscle, that only translates to an additional 28-50 calories burned per day.
So does this mean you should just become a couch potato? Not at all. Exercise can play an important role in weight loss, which ideally comes from a combination of diet and regular activity. Exercise will help you maintain the weight you've lost, and helps reduce the risk of certain diseases like heart disease, diabetes and high blood pressure. It also has mental benefits like reduced stress, more energy and better sleep. Just don't think you can eat a big piece of cake after a workout because you'll burn it right off.
When it comes to weight loss, have you found that diet or exercise is more important? Or is it a combination of the two that have helped you?
The report, published in the journal Exercise and Sport Science Reviews, studied people who did a moderate-intensity workout, high-intensity workout or no workout at all (on separate days). They also compared people of different age groups and those who were competitive athletes, versus sedentary obese and sedentary lean individuals. Throughout all of these comparisons, one result was consistent: There seemed to be no difference in how much fat participants burned 24 hours after a workout, compared to days when they didn't exercise.
This study looked at workouts that were under one hour in length, so researchers can't be sure that longer, more intense workouts would produce the same results. The study also discusses the popular belief that weight training dramatically increases metabolism. A pound of muscle does burn more calories at rest than a pound of fat. But most people don't put on enough muscle to make enough of a difference. For instance, if someone gained 4-5 pounds of muscle, that only translates to an additional 28-50 calories burned per day.
So does this mean you should just become a couch potato? Not at all. Exercise can play an important role in weight loss, which ideally comes from a combination of diet and regular activity. Exercise will help you maintain the weight you've lost, and helps reduce the risk of certain diseases like heart disease, diabetes and high blood pressure. It also has mental benefits like reduced stress, more energy and better sleep. Just don't think you can eat a big piece of cake after a workout because you'll burn it right off.
When it comes to weight loss, have you found that diet or exercise is more important? Or is it a combination of the two that have helped you?
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Comments
At over 300 pounds, I had over 80 pounds of fat. When I get to 160, I should have about 10 pounds of fat. I know full well that at 206, I have TONS more muscle than I did at 310. So... how much more muscle? Would that TONS be? Hmmm- they don't seem to go in the 'bass ackwards' direction, but I would guess well over 10 pounds of muscle gained in my journey. That is, what, a 100 calories RESTING difference. Add the caloric burn of the exercise itself- (I'm doing between 300-3000 calories burned in a day), and dang, I'm a calorie burning machine compared to the old days.
If your resting burn is 365,000 calories burned more in a year- or a mere smear 187,500 a year... heck, that's still pounds lost, or not gained.
Yeah, muscle!
Yeah, it's all good that we get to keep on doing it. That's the point here- not a one shot, ok, I'm done quick fix, but a lifestyle change... right? - 7/14/2009 8:46:55 PM
The main flaw that remained consistent in all the studies was the use of 'steady state' AEROBIC exercise protocols as the stimulus. Our aerobic energy systems use oxygen combined with glucose to create fuel for our bodies. Mother Nature made this an extremely efficient process for us to conserve our valuable energy stores. So of course fat metabolism and overall energy expenditure in a post 24 hour period will be insignificant based on this type of stimulus – the metabolic demand, in this particular case, is too low! This does not mean there are not cardio-respiratory and other great benefits of aerobic exercise (post workout or otherwise), there definitely is, but that’s another topic.
Now, if they substituted ANAEROBIC activity (resistance training) in this study, specifically a form which targets both the ATP and glycolytic energy systems, I guarantee you would see significant levels of post-workout 24hr fat metabolism. Anaerobic activity uses up the immediate ATP and glycogen (glucose) stores in our muscles for energy at a much higher rate. Up to 19 times more glucose is required with anaerobic exercise to get the same energy production when compared to the aerobic breakdown of glucose. (Note: glycogen is converted from the glucose in our blood stream which in turn is produced by eating and digesting carbohydrates)
It makes sense that in replacing these spent glycogen and ATP stores, we are using up excess ‘energy’ that would otherwise be converted and stored as fat. In addition, our fat stores are ‘dipped into’ and slowly burned up during our rest periods throughout the day/night because our overall metabolism is increased in order to fuel all the process that go along with strengthening, rebuilding, repairing and maintaining lean muscle tissue, ligaments and tendons. Not to mention the HUGE and much understated metabolic demand on our nervous system (including the brain) after intense anaerobic exercise. The brain uses 25% of our total body glucose utilization! Anyone that has worked with weights, bands or done HIIT/MET/Hybrid or plyometric training knows the mental focus and extremely taxing neuro-muscular requirements.
Other problems with the studies:
-The original study used subjects with above average fitness levels and VO2 Max capacity (42.6-45.0 ml/kg/min). They were already working out 3-5 times per week.
-On top of the already high fitness levels the intensity levels for the aerobic activity were considered moderate (avg. 66-67% of VO2 Max), not ‘high intensity’ as the study claimed. In other words, the workouts were not near difficult enough to illicit any significant change or adaptation in overall physiology or metabolism in these particular subjects – fat burning or otherwise. You can’t say, “Oh I went for a stroll in the park and was surprised I didn’t burn any fat the next day.”
-The ‘obese’ subjects in the supporting study were labeled based on the BMI index which is outdated and ambiguous (Most ATHELETES due to their high proportions of lean muscle are considered obese on the BMI chart! It’s not a sound measurement on it’s own). Plus they did not indicate there fitness levels, so we don't know how efficient they cardio-respiratory systems were in the first place.
There was more but, the main point that supersedes all is that the inference based on the the study is misleading from the get go (ie: aerobic activity at these levels would not correlate strongly to post workout fat burning in the first place).
I also take issue with the stat that the average fitness enthusiast gains only 4-5 lbs of muscle. That really sets the bar low for us, especially if you’re a male of average height. Potential for lean muscle gain is easily double or triple this with a proper program - no super genetics required!
The icing on the cake is that the original study was done over 8 years ago and was originally designed NOT to say we don’t burn fat post-exercise, BUT intended to dispel the notion that low intensity exercise was the most efficient for burning fat. Which it does successfully and I give it credit for, but this is old news. (By the way, it also recommends regular high-intensity exercise in the conclusion of the paper)
It’s obviously a case of some weak studies compounded on one another over time and the media has twisted it, taken it out of context and turned it into a sensationalistic headline with only half the facts.
The bottom line in terms of post exercise fat metabolism…YES, the correct exercise will turn up your 24hr post-workout metabolism and in turn burn fat for fuel!!
Of course eating properly and living a healthy lifestyle go without saying.
I hope this makes sense and alleviates some confusion…
Happy training,
BJ - 7/14/2009 8:24:28 PM
post=boost_your_metabolism_the_natu
ral_way - 7/14/2009 5:30:43 PM
The only way to lose weight is by having a calorie deficit - i.e, to eat less calories than you burn each day - and it is going to be very difficult to achieve this deficit unless one carefully monitors what is being consumed. How easy is it to overeat without even realising it? Nevertheless, every individual reacts differently to different things and therefore needs to be strong willed to keep on track to successfully reach their target weight.
I find that I have to chop and change the way I eat in order to keep getting results week after week. I effectively have to fool my body so that it doesn't get used to a particular style of eating and then adapt to it.
It is a huge battle, but great willpower will triumph in the end, we just have to consistently keep at it and not give in as soon as we meet a hurdle. - 7/14/2009 9:13:16 AM
That said, I can maintain my weight though portion control alone. I might even be able to loose some, but not much. When I'm really having trouble with my health (mostly migrianes), I frequently can't exercise. But at least I know that if I stay in my SparkRanges, I won't gain. - 7/13/2009 8:53:36 PM
Look at the time period that was tested and what was tested/compared. They didn't compare the overweight people's metabolism against the inshape peoples metabolism. They compared the metabolism of each person against THEIR OWN. So they tested it 24 hours after a workout and then tested on a day that there was no workout. They are comparing patient A (day one) to patient A (day two) rather than patient A vs. patient B. Also, it sounds like they did these pretty close together. So of course you're not going to see much of a difference. But if they would have tested them a few MONTHS apart . . . patient A (month one) vs. patient A (month four) . . I bet you'd see a difference in those numbers.
And I would have loved to have seen the comparison between patient A (overweight) vs patient B (in shape). I can almost guarantee you that the numbers would be totally different.
It's always good study to read exactly what they're comparing . . . shines a bit of light on the "Breaking News Working Out Doesn't Affect Your Metabolism!!" hype.
Of course it does!!!
any one of you who've been working out regularly and eating healthy KNOWS how much better you feel!!!! - 7/13/2009 2:07:56 PM
On the other hand, my diet seems to make more difference in how my waist and stomach look, regardless of how much cardio and crunches I'm doing! Too much sodium and sugary carbs, too little fiber = belly bloat, even if I'm working out for an hour and a half a day.
All that being said, weight loss is easier and generally more consistent when I am watching my food intake too. - 7/12/2009 10:30:05 AM
This is all supposition on my part.
It does make sense though....most of our body is muscle and muscle needs to be worked to keep it in shape - even our brain to some degree is like a muscle.
Good article that is giving me an ' ah ha' moment......revelations come in all shapes...lol - 7/12/2009 7:21:21 AM
- 7/11/2009 10:29:19 PM
Also, I have a co-worker who started jogging about the same time I started walking and changing my eating habits. She chose not to change her eating habits. We both walk/jog 3X per week, and she has not lost any weight while I have lost 25. Granted, with my weight, I know that I will lose much faster than someone who only has 20 pounds to lose, but I think this is a testament, that exercise alone is not the key. - 7/11/2009 8:10:03 PM
I saw a trainer and a nutritionist every week last month. It has helped me tremendously! The nutritionist said that I don't want to be a smaller version of myself. I said "I don't?" He explained that if you just do cardio sure you will lose weight, but you will still have flabby areas - so basically smaller but not as toned as you could be. With weight training, you will be able to tighten up problem areas and help reshape your body - and you cannot weight train without proper nutrition.
He had me eating 6 times a day, lots of green vegetables and protein with EVERY meal. I was able to reduce my body fat percentage by 5% in 2 weeks! Conversely, my friend whom I was splitting the cost of the nutritionist and trainer with decided not to follow the nutrition plan but worked out the same as I did. Because she was eating a lot of junk, her body fat percentage went up. Sure she lost 2 pounds - 2 pounds of muscle!
I believe proper nutrition and exercise go hand in hand if you are looking to rev up that metabolism. - 7/11/2009 6:32:12 PM
So, I'm a believer in aiming for good all round habits, and accepting the reality that chances are slim I'll ever be 100% perfect. - 7/11/2009 5:28:14 PM
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