You can’t out-exercise your mouth.
It is a fundamental truth and a brilliant evolutionary strategy. Exercise has many interesting impacts, both positive and negative, but if you’ve been chronically obese, I want to encourage you not to start here. Not only are you putting your heavy, out of shape body into an increased risk of injury, but until you’ve been successful in the one exercise that ALWAYS works, you’ll simply eat your way through any progress.
What is this magical exercise? Isometrically clench your teeth in the presence of fattening foods and excess calories. It’s necessary to control appetite, not “fuel your body” with even more energy. Those shakes are only helping to the degree they are displacing higher calorie food. Take a look at any study that shows statistically significant effects usually has paltry overall results (normally far less than 2 lbs a week).
It seems many emails, blogs and conversations all end up with the word cravings sprinkled on top. Somehow we are to believe that because we crave something it’s an indication of need. Our cravings are about as good of indication of nutrition as the food pyramid or the Hot and Fresh sign at Krispy Kreme. I’d argue they are practically worthless and craving is a term of addiction, not survival and health.
You can’t out-exercise your mouth.
Let’s take a look at a few exercises and some of the claims about metabolism and I think it will be clear that exercise has many of benefits, but burning fat is not at the top. I apologize in advance that this is going to get a little technical, but it’s absolutely necessary if we ever want to expunge the nonsense from the weight loss and fitness industry. This was the most difficult blog to write to date, because I really want everyone to understand this concept. It is so critical and I hear EVERYONE throwing around the M-word as if it is undeniable fact.
Wired For Truth
When Steven and began discussing a proposed article (read Wired article here), he kept coming back to the same question: how can we know that cold had a certain impact on your progress? I guess the simple answer was that I changed so few variables that the impact was self-evident, but the far more certain way is to measure. My goal was to lose weight back in 2008 – not write a book, a blog, interviewed in magazines and TV, or give a talk. I didn’t really care much about ANY of this until June/July 2009 when so many others, like Tim Ferriss, made such a big deal out of the results. I just did it because it made sense to me and it did have a solid technical basis. I didn’t know for certain that it would work.
Since then a combination of defending the results and being encouraged by scientists I enormously respect to take it further has fueled the crazy self-experiment obsession. Along the way I haven’t given much thought to proving a point as much as understanding the underlying science. That gives one a certain intellectual freedom, because it doesn’t matter what the answer is as long as it is the truth.
We now have seen in Muscling Part 1 and Part 2 that metabolism has two important components: RMR and RQ. The first, RMR, is a short term measure of a person fasted at rest and that measurement (typically about 15 minutes) is projected over the next 24 hour period as an estimate of total energy should be used if no additional activity occurs. It’s in a sense a minimum, or floor measurement and your total expenditure will likely be higher over the day. RQ (respiratory quotient) is a breath by breath analysis during the period measured of the % Fat and % Carbohydrate being utilized. It tells us how much of each fuel is being used. Like RMR, RQ is EXTREMELY sensitive to activity and is constantly changing to accomodate the body’s fuel needs.
When Atwater and others performed their experiments a century ago, they were not only collecting the carbon dioxide exhaled, but also the heat that evolved from each test subject. This would be direct calorimetry, because the heat evolved during this oxidation (burning process) is related to the fuel burned. Not only can it be measured – it can be measured very accurately with simple thermometers of the day. Today, indirect calorimetry, measuring O2 consumed and CO2 produced, indirectly determines the energy dissipated and it matches what they measured over 100 years ago.
Over a century…that’s pretty incredible.
So if someone is talking about boosting metabolism, lean mass burns more than fat, or post exercise/eating metabolic boosts, remember that one can’t simply repeat these things and it suddenly makes them true. We actually have to verify that it is as stated. The simple question one should ask is: how do you know? So let’s blow a few more metabolism myths out of the water.
What’s Your RQ?
We’ve learned RMR, or metabolism rate, during any activity isn’t enough to know anything about fuel source. You might be burning alcohol, carbohydrate, fat or protein – you don’t know. While your diet does influence short term calorie consumption (within hours of the meal), it really has no impact on the bigger picture of what happens for the remainder of the day or what fuel is selected for your exercise of choice.
To assess that, we need RQ. This you will remember is a ratio of the CO2 produced to the O2 consumed and the number is very specific to the type of fuel used. Let’s use for example an alcohol lamp burning grain (ethyl) alcohol for fuel. Alcohol has an RQ = .67 and when I drop this alcohol lamp into a bucket and sample the air continuously that’s exactly what I measure – a straight line at .67 and a RMR of 5,074 kcal per day. That lamp fire is a little over the energy equivalent of two people to put it in perspective If I weigh the lamp before and after the experiment, I can in fact verify that not only is my system displaying the correct RQ, but also measuring the overall energy accurately.
By using calibrated gas mixture of Carbon Dioxide/Oxygen, a calibrated syringe to measure volume displaced on each breath, and alcohol flame to assess the fuel consumption rate, we can KNOW what is happening before/after a meal or before/during/after an exercise. This isn’t new, in fact we learned in Muscling Part 1 that this exact technique was used back in 1790 by Lavoisier and later by Atwater and others after the discovery of the macronutrient fuels, protein, carbohydrates, fats, and alcohol. With all biological systems there is a certain variability above us, but we got these measurements correct. How we decided to use them is a completely different story.
It should come to as no surprise to anyone that reads this blog that the terms “protein, carbohydrate, fat” are not the arbitrary “food labels” your, government, food packager, dietitian or fitness coach chooses to place on the items that constitute a meal. In fact it was the process of making these measurement that I came to realize how absurd these labels are unless your goal is to over eat calories in pursuit of some magic macronutrient “ratio” or every nutrient inclusive, “balanced meal.” Either way, I am pretty certain when we measure activity, meals, sleep, mild cold stress, etc… using indirect calorimetry that we can know with some accuracy and precision how much energy the body is using and what it is burning to get there.
Taking a Swing at Kettlebells
I will take some “heat” for this, so let me begin with the same disclaimer I’ve given on exercise in general. We shouldn’t throw the baby out with the bathwater. Even though I don’t think exercise is a particularly good way to lose weight (in fact it mostly slows it down), does not mean I am opposed to it or think it is unhealthy. Likewise, I love kettlebell swings, so please don’t take this as some sort of assault on exercise or even kettelbells in particular. This just happened to be an easy target. I could have used nearly any “fat burning” activity aerobic/anaerobic to make the point.
Anyone that’s performed these exercises will tell you that they are a great physical exertion, but what happens when you have a $30K machine that let’s you peer into what makes that swing FEEL so good? What’s really going on? I want you to take a minute and Google: kettlebell metabolism
You should get MANY hits. WOW. look at those very first ones:
“A short and intense kettlebell workout will crank up your metabolism for another 38 hours.”
“This will elevate your metabolism for up for 31 hours.”
“If you want to burn more fat, improve your fitness, and ramp up your metabolism, try doing kettlebell jumps at the end of your workout.”
“Kettlebells can help to stimulate a metabolism because of the way kettlebell activities force a body response through balance challenges and resistance.”
…and so on
We KNOW it’s repeated over and over (I’ve said it, >gulp<), but I can tell you that it simply is not true. If you are a personal trainer, a fitness blogger, or a writer, let’s take the time to verify what’s repeated. If we could just spend a year on correcting the myths, we’d all be better off. Isn’t everyone sick and tired of the contradictions? Once again, I love kettlebell swings and have my own routine developed for post-weight loss physical conditioning (I am close to testing it out on a increased strength/fitness challenge after my next weight loss tests are completed in June/July).
What’s the truth?
Let’s review that MOST people will post a resting RQ ≈ .85 and that corresponds to ~ 50/50 CHO/FAT ratio. This means if you wake up in the morning and have a pulse, you’ll expend about half of your daily RMR calories from fat oxidation. But what happens in explosive exercise, like the kettelbell swings I had Steven do? First, here’s the exercise: a simple 20 second swing, 10 second rest period, repeated 10 times. We began with a full RMR/RQ test earlier and then the test protocol had him standing still ready to exercise for 3 minute “starting” RMR/RQ.
I’ve tried to simplify the plot to highlight the changes in Steven’s metabolism. In this case we see his cumulative calories burned vs time (red line). You can easily see when the rate (kcal/min) changes by looking at the slope of the line. The steeper the slope, the more energy Steven is burning in that period.
We see that he starts out during a 3 minute rest, or baseline period, and then the exercise begins. He continues to exercise until the 5 minute mark at elapsed time of 8 minutes and then we look for recovery. The blue dashed line I’ve added represents the calories he would have burned had he just stood there. The entire test is over in 20 minutes.
So let’s do a couple of checks to make sure we are in the ballpark. At the far right hand side you see the dashed line ends up at ~ 44kcal/20 mins. An hour is 3 times this, so this would result in an RMR of 132 kcal/hour (3 x 44), or 3,168 kcal/day – quite a lot for a guy that is 5’7″ and 134.9 lbs.
But that is correct, because his true RMR (fasted and lying relaxed) measured a couple of hours earlier was 1,984 kcal with an RQ = .80 and now he is standing and probably a little nervous before the test. Here I want to demonstrate just how variable the number is we all call metabolism. His total calories burned in 20 minutes was 70 kcal, but 44 kcal would have happened anyway, so the total burned due to the swings was 26 kcal – a little more than a half teaspoon of coconut oil or a little under two teaspoons of table sugar. When people (even me) do these hard calculations of calories in/out, note that the out portion can be widely varied. We will come back to FAT/CHO burned, let’s continue with the metabolic “boost” everyone is raging about.
Follow the red line. You see it ramp up with activity and then as soon as he puts down the weight, he begins to recover. Your metabolism is dynamic and designed to conserve. I estimate that the energy rate hits pre-exercise level about a minute or so after he’s done – worse case let’s call it two minutes. Ok, but energy is only half the story, so let’s turn to RQ.
Where’s The Boost?
It’s simply not there in energy consume, but perhaps it’s buried in the RQ as raging, metabolic fat burning. Let’s take a look. You’ll see 4 sections and in each a box with RQ average for that section. These four divisions approximated when shifts in his RQ occurred. He begins at RQ = .84 (47.2% CHO/52.8% FAT). During exercise this climbs to RQ= .98 (93.6% CHO/6.4% FAT) and then to an average RQ = 1.02 (100% CHO) during the recovery phase which lasts about 8 minutes. During this time his RQ is drifting down and by minute 16 he’s at RQ = .87 or (57.5% CHO/42.5% FAT). We end the test at minute 20.
The truth: His metabolism returned to normal after 2 minutes and his RQ within 8 minutes. Sorry folks, no raging metabolism – it was news to me as well. We’ve been duped.
It’s not rocket science and exercise physiology has taught for a long time that these explosive energy modes are not driven by huge utilization of fat. Elite endurance athletes burn more fat than the rest of us, but they typically don’t burn 100% fat during the activity. Volume training encourages their body to burn fat earlier into the exercise and that avoids the carb-crash when glycogen stores are spent.
So why does everyone say it? Why is it repeated, debated, instructed when it’s so easy to disprove? Perhaps, sometimes people want to believe in something so much, they begin to use the words think and believe interchangeably and in doing so, avoid the thinking part all together. Today, there are many similar examples I’ve found food, blood sugar, etc… and in time will demonstrate. Internet has facilitated an explosion of fitness/diet bloggers and monday morning scientists that read a handful of papers, use many multi-syllable words, and back it all up with citations at the bottom of the page, but never measure. I guess it’s an intellectually toxic cocktail of incompetence and ignorance, but I’m afraid it’s no longer the exception.
One might expect this from evening and weekend warriors, but we hear this from degreed, educated, trained, and certified people as well. I will admit I have said it before and there is simply no excuse for it. I’ve spent the last four years in an obsession to get to the bottom of something that’s quite easy to understand once you get the memorized drivel out of your head. It was an expensive “hobby,” but I’m prepared to change the lives of 10,000 people and I don’t intend on selling pills, powders, screenings, and procedures. I am after real, measurable, demonstrable and accountable change for a more healthful life. In the mean time, let’s just not forget:
You can’t out-exercise your mouth.
Chilling Truth About Cold Water

Steven sitting at the bottom of the swim spa for a 20 minute immersion to measure calories and %FAT/CHO during an immersion test.
Swinging Kettlebells is not why Steven was visiting my home lab on that hot, humid summer day. He was here to learn more about cold. By now anyone that reads my blog knows that I am not really an advocate of misery and lean toward mild exposure over longer time. That’s simply not something one can easily test during a hot, Alabama August day and he was only here for 5 days, so we did the next best thing, turned down the thermostat.
I have an 8 x 14 ft Tidalfit swim spa that’s temperature regulated from 45F to 105F (~8C-40C) using an AquaCal heat pump. Our goal was to compare 20 minute swims at 80F (26C), 70F (21C), and 60F (15C). We also looked at a 20 minute jog at a leisure pace of 5 MPH. In all cases we wanted to bring the exercise level down a notch testing to what extent the advertised “fat burning zone” exists.
Finally ,we performed two immersions, where the goal was to “relax” as much as possible so that the cold portion of the contribution would be separated from activity. At that time, my calorimeter was relatively new and so this represented the first opportunity to really dig in with a complete set of data keeping in mind the the foundational science is over 100 years old. We weren’t really challenging old science, but rather adjusting the collective “mind hive” speak that’s resulted from people repeating incorrect, or generalized, “facts” over and over until it becomes widely accepted.
Let’s discuss the big picture here and compare/contrast swimming with kettlebells. Again, so as not to be misunderstood, I am not suggesting kettlebell swings or weight lifting have no value. My goal is to focus everyone on misguided notion that metabolism, or lack activity, is the reason they are obese or even the reason the last stubborn “belly fat” is hanging around. As well, I want to assert that other than dietary intervention, most exercise is an activity revolving around glycogen and doesn’t really impact or significantly decrease your body fat levels.
We basically live in this realm of RQ = .85 (50/50) and exercise always moves that number UP not down. Elite endurance athletes burn more fat and volume training makes it better, but for the average person, all of that sweating and jumping creates far more metabolic needs of repair and risk of injury than warranted by the amount of body fat consumed.
In THIS regard, a calorie isn’t a calorie – not because they aren’t equal, rather, because an activity may preferentially prefer one fuel over the other.
In every case of activity analysis, I want you to also remember this imaginary slope upward and it’s progress over time. Before you begin, the energy expenditure you would have burned had you not exercised, could continue on for the same time at the gym. Now add exercise and your metabolic rate increases momentarily and then when you stop, it goes back to the original rate after some period of time. During the increased rate of calorie consumption, our cells shift toward the glucose/glycogen economy unless one is completely glycogen depleted.
Swimming is actually fundamentally different from all other forms of exercise. First, it’s not an activity of explosive power, it’s a sport of technique. I’m not suggesting elite swimmers aren’t powerful and explosive; sprinting can occur in competitive races. One can swim leisurely and significantly reduce the exerted force, but there’s another prominent change in the thermodynamic balance: the rate of body heat loss to the water. What we are doing effectively is pulling the heat from the outside instead of pushing it outward by revving our muscular engine and creating obligatory waste heat.
With that let’s turn once again to Steven’s cold tests. I’m not going to go through all of them at this time, but I want to point out a few things that should become second nature. First, take a look at the “shape” of his curve swimming. You see the same basic shape as in kettlebell swings above – the gentle slope, then steeper when swimming and finally back to the original slope. Nearly all activity fits this general picture as did his 20 minute jog. If we ramped up the swimming effort (or even running speed) that middle section would have progressively steeper sections, but it does return back to “normal” or resting at some point after and we demonstrated it’s way less than 30 hours.
Remember that metabolism, or energy consumed, varies throughout the day, but the total energy is only HALF of the story and not even the most important half for most of us. The number we are after is RQ, which gives indication of how much fat consumed in any given time. If weight fat loss is your goal, this is much more important.
Taking the Plunge
With swimming, there is a distinctively different signature on RQ. This was the middle case, a 70F (21C) 20 minute swim followed by ~ 25 mins of post swim monitoring. First, you’ll see that Steven starts out just like any other activity and then he moves into the actual swimming phase with the increase in metabolism. Once finished, he gets out and recovers (on a HOT August day) while continuing to measure.
Swimming burned ~130 kcals, but what is really interesting is RQ. It starts in a normal range of RQ = .82 (40.3% CHO/59.7% FAT), rises during the swim to RQ = .98 (93.6% CHO/6.37% FAT), and then he begins the recovery phase. There is a little twist here in that Steven was shivering for the first 8-9 minutes. Not violently, but definitely shivering (see video from WIRED article upper right) and we see a slight drop to RQ = .95 (84% CHO/16% FAT). Then the shivering ceases and RQ falls to .75 (12% CHO/88% FAT) where it remains until the end of the test.
The numbers were almost identical minute by minute for a swim at 60 F and at 80F it looked much like one would expect for running or other activity. Mild cold stress, as has been reported begins at 80F, but it requires longer exposures with less activity. I didn’t repeat the same at 75F, but I feel pretty certain through other measurements that’s where the upper end of the temperature range is located.
We also did immersions tests and this also turned out interesting. First, I had him divide the 20 minute exposure into five sections sequentially immersing: feet, waist, hands, shoulders and head. 80F was somewhat uneventful as one might imagine on a hot Alabama afternoon – he smiled way too much. Now, 60F was way more fun – for me, not him. First, the the data didn’t have the sharp change in slope like all the others here, they were much more subtle. There was a change when his feet went in and it stayed constant until his shoulders went in and there was a larger change. That’s where it ends, because we measured for a total of an hour, but 37 minutes after steven exited the pool his metabolic rate still had not return to baseline. RQ was a different animal.
Despite his sitting motionless for the entire test, RQ matched swimming, almost to the minute , the results seen during the 70F/60F swims, with the exception of the “activity phase,” where RQ peaked at .88 (60.8% CHO/39.2% FAT) as compared to RQ = .98 swimming. Once he had overcome the 8-9 minutes of shivering on exit, (probably felt like hours to him) he was once again down to RQ = .74 and remained here for last 25 minutes with no shivering until the end of the test at 1 hour. We don’t know how much longer it would have continued.
Final Thoughts
What does this mean practically speaking? The sweet spot for swimming is likely somewhere in the 65F-75F range and you simply have to pick a temperature where you feel most comfortable. It’s best to swim at a leisurely rate – don’t push it. When you get out of the pool – don’t jump in the warm shower or hot tub – that defeats the purpose of the heat deficit created by the mild cold stress. I’ve seen data that suggest free fatty acids remain elevated for hours and it’s most likely the body’s upregulating mitochondria via UCP-1α using fat to produce replacement heat. This might also explain and be directly related to the connection with exercise and the hormone irisin, which encourages new BAT growth (see post: A New Eye On BAT). I’ll add that this is also why you’ll want to stay away from a high calorie meal in the window following the cold stress activity, which could shift RQ away from fat and it’s best if you don’t eat at all. If you are going to eat, I suggest a high fiber, nutrient rich/calorie poor meal. That being said if weight loss is your goal, use a high fat diet of thunder thighs, beer belly and big butt as your primary fuel. It won’t go away until you metabolize it.
I think it should be obvious why one should abstain from exercise if you want to lose fat rapidly. First, your muscles don’t atrophy overnight. I am not asking you to lay perfectly still, just don’t do anything that looks like a repetition or makes you sore/sweat; living is enough activity. Walking, going for a leisurely swim, or biking is okay, but don’t turn it into a race. Playing with the kids, throwing a frisbee or walking the dog all keep you active. Your body KNOWS it needs to burn fat on a restrictive diet and it’s not going to burn lean tissue just because it is there.
On the other hand, if you insist on tearing down tissue exercising, every time you do you are shifting the body away from fat burning (rise in RQ), post exercise recovery DOES require food to fuel the tissue breakdown/repair, and the chance that you’ll maintain these needs/consumptions in perfect balance is low. The more common tendency is to over eat. No one I have coached has loss lean muscle mass, but certainly their apparent “strength” goes down. This okay, because there is muscle memory and a few weeks in the gym once the ideal weight is reached and you’ll be back to where you began.
The sports research we tap into when generalizing to the population at large was mostly performed with the idea increasing performance/endurance. For many of you that is a goal and not competing doesn’t win the gold. Exercise is an option for the rest of us. The problem of course is that we’ve taken this information with a broad brush and painted it onto every person overweight and suggested this obesity pandemic is one of inactivity. I don’t believe this is the case. When one makes an informed decision about how they want to lose weight and has a choice between rapid weight loss without significant exercise or slower weight loss and risk of injury with it, then they are actually choosing.
On the other hand, blaming the weight issue on a slow metabolism, lack of activity, or avoiding the connection that one is chronically over-nourished, obfuscates the problem and frustrates the person trying to make a change. Finally, we have the ridiculous, ubiquitous metabolism claims bombarding us every day. Your metabolism likely isn’t broken unless you don’t feel a pulse and then it doesn’t matter much. You might have metabolic dysfunction due to chronic over nutrition, but that can be greatly improved, or completely reversed, with proper diet. Why have we all become obsessed with being “diagnosed’ with dysfunction as opposed to seeing the overwhelming evidence that our society is deluged with cheap, ubiquitously available, cheap food. We eat too much – stop eating and you’ll see instant results.
This post is not gear toward elite athletes, or any competitive athletes at all. There are ways to exercise at lower levels of RQ. The point I am trying to make centers on the barrage of metabolic boosting claims and “fat burning zones,” which all disproportionately suggest that if a person is overweight, lack of activity caused or was a major contributor and more activity is going to fix it. The root problem is one of intake not output. Either way, we need to all understand that no matter how hard we work, our ability to eat and the modern day access to enormous calorie sources must be taken into account.
I am certain that weight loss is a catabolic process and it’s a process of conservation, not excess. If you want to run faster, jump higher and swim farther then you won’t succeed without conditioning. Although after my two year exercise hiatus, I have been thinking about challenging that notion too. Certainly there’s nothing wrong with exercise and many benefits, but fat loss, especially rapid fat loss, isn’t one of them. You might say, but it makes me feel so much better and I would reply you can get the same serotonin hit from mild cold stress in a contrast shower, stop eating, get within striking distance of your ideal weight as soon as possible and then resume exercise. It is a choice and it’s not the only way, but the myth of metabolism pushes many in a direction that ultimately fails.
That’s all for today. whew, got through it and I know I lost a few of you, but hopefully you’ll stick with it.
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