My new TEDxBundaberg talk about breathing and weight loss

I hope this sheds some light on how your body and fat cells gain and lose mass. Any questions, just ask.

23 thoughts on “My new TEDxBundaberg talk about breathing and weight loss

  1. Hi, I saw this video and I was wondering, do you know of any kind of pre-made calculator that can input sugar, fat, etc from nutritional labels, and turn it into an amount of time needed to exhale it, as you did for the foods in your ted talk?

    If not, I have some web programming skills and I would love to have a quick chat and work through the maths with you and make the first one. I think it would be really useful for people to visualise how much time it takes them to exhale their food, I found myself wanting to calculate how long it would take me to exhale a bar of chocolate, but I don’t have the slightest chemistry knowledge :P.

    Please contact me at if you are at all interested in having a chat, the ted talk was very eye opening and i’m trying to share that knowledge because I believe it is very valuable. Teaching this to kids (and adults) should be mandatory everywhere.

  2. Hi Ruben,
    Thanks for all the great information you provide online. I have a question about a surprising result from my Garmin fitness tracker following my breathwork sessions. The Garmin is a wristwatch device that measures heart rate and provides, among other things, estimates of caloric burn for various activities, apparently based on time between heartbeats and my height/weight data. According to the watch, my Wim Hof-style deep breathing sessions (which last about 25 minutes) burn nearly 700 calories! The calorie burn estimates for my other activities are within the expected range so I don’t think the device is defective. Is it possible that the breathwork estimate is correct? If so, would that be due to the expiration of carbon dioxide itself or to the physical work required for deep breaths? Thanks for any clarification!

    1. Hi Rebecca,
      Good question. I’m not familiar with the algorithm the Wim Hof Method app uses to calculate energy expenditure or how it was validated (it’s also available for the Apple Watch) but exposure to cold can cause up to a five-fold (5x) increase in the resting metabolic rate. That means you’d be consuming 5x more O₂ and producing 5x more CO₂ than when you’re in the “thermoneutral zone”. The average resting metabolic rate for women is ~1400 kcal/day, which is roughly 1 kcal/minute. A five-fold increase therefore raises the metabolic rate of an average woman to ~5 kcal per minute so, at that rate, you would expend 125 kcal in 25 minutes. Your 700 kcal figure does sound a bit high but I am not sure what else you’re doing during Wim Hof breathing session? The “work of breathing” is about 0.3 to 0.6 joules per litre of air. Adults breathe about 360 litres of air per hour so that’s 108 to 216 joules, or 25 to 50 kcal, which does not account for the addition 575 kcal… but perhaps there is additional physical activity in the Wim Hof method that does for that. I’m not sure but hope that helps to get you started.

  3. I appreciate this reply and the explanation of the “work of breathing.” My breathing sessions don’t involve much movement apart from breathing – exceptions might be some exaggeration in the chest to accommodate very deep breathing and also periodic “breath retentions” for one to two minutes after exhaling. So I suspect the 700 kcals overstates my exertion. Cold exposure is also key to the program (not during deep breathing sessions) so I’m very encouraged by the significant increase in resting metabolic rate!

  4. This was a great talk.
    I loved the time it took for food to be breathed out.
    What was the formula for working this out?
    I need to loose weight and I seen that and thought that would be a great way for me to convince myself not to bang on the sunday or skull another solo.

  5. Dear Ruben,
    I am very interested in science since I was a little child. So I always thought about the exact same thing as you. The more you respire, the more you can eat. But then I was thinking about anaerobic fermentation. That would happen whenever you don’t breathe properly. When that happens, you don’t have enough oxygen to respire normally and therefore also don’t loose weight, even though you are exercising, because the carbon doesn’t leave the body due to missing oxygen to pair with.
    This would lead to the conclusion that it is very important to learn how to breathe properly. Also, you should train your lungs and heart so that they can provide enough oxygen.
    Today I saw your Ted talk and I found that all my thoughts were there except for this last one. How do you think about it?


    1. Dear Rashid,

      Good to hear from a fellow lover of science. This is actually a very frequently asked question with a very surprising answer.

      The first surprise is that the oxygen molecules we inhale do not become the “O₂” in the CO₂ we exhale. Inhaled oxygen is converted to water.

      This happens in a series of chemical reactions catalysed by enzymes collectively referred to as the “electron transport chain”. The enzyme that splits molecular oxygen (O₂) into two separate oxygen atoms (2 × O) is called “cytochrome C oxidase”. The hydrogen atoms added to the oxygen atoms to form the final product (H₂O) of these reactions all come from food.

      But that leaves another question: where do the oxygen atoms in exhaled carbon dioxide come from?

      The answer is water molecules and it happens in the Krebs cycle, also known as the citric acid cycle, or the tricarboxylic acid cycle (TCA) cycle.

      The hydrogen atoms that are removed from the H₂O in the Krebs cycle are used in the electron transport chain, where they are married to the oxygen atoms we inhale. This all seems very redundant and unnecessarily complicated but that’s aerobic respiration works.

      In the absence, or during a shortage, of oxygen molecules, the hydrogen atoms removed from H₂O in the Krebs cycle get “stuck” with nowhere to go, and the process grinds to a halt. When this happens in a muscle, glucose is “fermented” to lactate. That, in itself, is a two-step process. Glucose is first split in half to form two pyruvate molecules, and these are both converted to lactate. The lactate molecules produced are then transported to the liver, where they are converted back to pyruvate, and then back to glucose in a process called the Cori cycle.

      All of this happens in all of your cells, not just in your lungs. Therefore – and to finally answer your question – it does not really matter “how” you breathe. As long as there are enough oxygen molecules and water and food molecules floating around in your cells, they can carry on doing what they do.

      However, “how” you breathe can affect the amount of carbon dioxide in your blood. Hyperventilating will remove more CO₂ than you produce, and will lead to a condition called “hypocapnea” which means “not enough CO₂ in the blood. This can manifest in a constellation of symptoms including dizziness and potentially a loss of consciousness. Hypoventilation (i.e. not breathing enough) can lead to hypercapnia, too much CO₂ in the blood, and a different set of symptoms.

      Regards, and I hope that helps,


  6. Nice, but as a scientist (I’m a math professor) I have to disagree with your math. You claim that 10 kg of fat gets turned into 8.4 kg of CO2 and 1.6 kg of H20, but that doesn’t make any sense to me. If you use the chemical formula at 1:58 you get that in order to burn 10kg of pure fat you have to inhale 25.9 kg of oxygen, which then gets turned into 25.1 kg of CO2 and 10.8 kg of H2O. So basically, you exhale as much as you inhale and you end up with approximately the same weight of water as you had fat!

    1. Dear Sander,

      Thank you for checking in. It’s great to hear from people who enjoy these numbers.

      That slide did not translate into the video very clearly, unfortunately, but there is a brief moment when all the numbers are correctly displayed. You can get a longer look at them in the published paper on the British Medical Journal’s website (Figure 2, Page 3):

      It actually takes 29.0kg of oxygen to fully oxidise 10kg of fat (not 25.9kg), so we start with a total of 39kg of reactants. The complete oxidation produces a total of 28kg of CO2 and 11kg of H2O.

      Of the 28kg of carbon dioxide, 8.4kg comes from the atoms in the fat, and the remaining 19.6kg comes from the atoms in the oxygen.

      Of the 11kg of water, 1.6kg comes from the oxygen atoms in the fat, and the remainder comes from the oxygen.

      I hope that clears up the confusion.

      Kind regards,


  7. Ruben, your TEDx Talk was fantastic. I can only learn and remember by illustrations, is there somewhere I can get a copy of all the slides from your TEDx talk. I didn’t do science at school years ago, now I wish I had, ironically I took Home Economics now I am trying to get rid of 20kg, your talk was so clear to me, I need to learn about atoms.

    1. Dear Jenny, apologies for the delayed reply and many thanks for your kind words. I don’t have my slides in a format that works very well on a static page… each one has multiple animations so they’re a mess when printed as PDF’s. There’s no need to have any regrets about not doing science at school because the science curriculum did not and still does include any of these concepts in a sequence or format that allows students to connect all the dots between their stomachs and their lungs. As I said in the TEDx talk, the trick to losing weight is to exhale more carbon atoms than you eat. There is already a tried-and-tested, scientifically validated way to do that, which is to count kilojoules (or calories if that’s your preferred units). In fact, dietitians measure metabolic a person’s metabolic rate by measuring how much oxygen they consume and carbon dioxide they exhale per minute. Calorie counting has become so unpopular that some people claim it doesn’t work, but it most definitely does. Good luck with your weight loss. I found cutting out the 3-4 large cappuccinos I was smashing everyday to be a very effective way to reduce my intake because that’s one litre of milk, which is a whole meal worth of extra calories on top of what I was eating… and walking for an hour or more a day.

  8. Hey I really like your video, just watched it on youtube. I had found this information somewhere before, that the fat essentially gets breathed out. I wish you talked more about the specific hormone that breaks down fat during exercise (is it during exercise or does your body change when you exercise so that it naturally metabolizes more fat?). Also I wish you talked more about alternative forms of weight loss, not because they are attractive alternatives but just because of the mechanism whether it’s the same or different. For example cancer patients frequently lose weight which I assume is because they lose their appetite. There are other changes, hormonal imbalances, that can cause loss of appetite. I understand that liver ailments cause loss of appetite. Some people lose weight by taking amphetamines, so how does this work in the body?

    So what I’m getting at is that I wish you talked more about the actual chemistry of fat becoming CO2 and H2O although yes I understand the focus of the lecture had to be the essential fact that fat becomes CO2 that we breathe out rather than turning into poop.

    I know that you are the scientist and I am not, but I disagree with your statement that you “just eat less and move more.” I understand this worked for you but I suspect there is more to it. I am certain that you eat a healthy diet. If you eat processed foods, especially dangerous processed foods, I am certain that this interferes with the process of losing weight. There is a really good movie called Fed Up about the food industry in the United States that discusses this. I believe it’s on Netflix or Amazon Prime or something. Basically it’s about obese people and the relationship between the growth of obesity (yes I meant it, I might pick a pocket later too) and the perverse incentive of the American food industry.

    I would also like to point out that losing your little belly roll is a vastly different enterprise from stepping away from massive obesity, and the precept of “just eat less and move more” is fundamentally unhelpful to most really fat people. I just believe there is more to it. You need more dietary constraints than just “less.”

    I am curious what you think of calories as a measure of food? I believe it is a very imperfect measure of the impact of food, arguably only slightly more useful than measuring the physical weight of the food ingested. People widely believe that their bodies burn energy from food. And calorie count by the way is measured by burning foods. To me it is so inherently false a measure. If you take calorie count as a measure of the impact of food it seems as though you have to measure the calories going into the body and the calories going out of the body to have any idea. And I can pretty much predict that it is unlikely a scientist will do that work.

    Anyway thanks for your video and I hope my point of view is not too annoying for you. 🙂

    1. Hello Pajamasfta and apologies for the delayed reply. Yes, it would be good to do a deeper dive but TEDx talks are limited to 20 minutes maximum so time is the issue. I have seen Fed Up, very interesting. I agree that simply telling people with obesity to eat less and move more, with no further support, explanation or guidance, is unhelpful. However, the reality is, in order to lose weight, more carbon atoms have to leave the body via the lungs than enter it via the alimentary canal. There is plenty of research demonstrating that any diet can result in weight loss as long as there are less carbon atoms (calories) going in than coming out. The question is, how do people feel when they consume different diets? Which one can they stick to and enjoy and will they get all the micronutrients they need? This is where I defer to the dietitians who are the experts. Thank you for your note.

  9. sorry a couple other points.

    1) you said CO2 released from your body does not contribute to global warming but that seems a little bit misleading. If you release CO2 from your body essentially yes it does contribute to global warming but on a scale vastly less than the use of carbon fuels. One gallon of gas becomes almost 20 lbs of CO2 and before the pandemic I was driving 100 miles a day so my weight loss compared to driving the first one percent of my daily commute was negligible.

    2) Aren’t the carbons in your food a better indicator of the potential fat creation of food than calories?

    Okay thank you.

    1. Hi again Pakamasfta, quick answers to your questions:
      1) Imagine watching a movie of yourself backwards and imagine you could watch every carbon atom you exhale, in reverse. Rewind the film far enough and you’ll see that every carbon atom you breathe was CO₂ less than a year ago. Plants turn CO₂ and H₂O into food and oxygen, we turn food and oxygen back into CO₂ and H₂O. The net result is that there is no change in the total CO₂ in the air. When you burn fossil fuels, you are returning carbon atoms that have been buried for millions of years back to the air. That increases the total CO₂.
      2) Unfortunately, it’s not that simple. Glucose molecules have one oxygen atom and two hydrogen atoms for every carbon atom. Fatty acid molecules only have two oxygen atoms but up to 20 or more carbon atoms, with hydrogen up to 40 or more hydrogen atoms attached. The calories in food come from breaking the carbon-hydrogen bonds and reforming carbon-oxygen bonds to make CO₂ and hydrogen-oxygen bonds to make H₂O.
      I hope that helps.

  10. Hi, so we are clear, dietary fat can’t be used for energy? The fat we have on our bodies, adipose tissue, triglycerides etc., they can’t be used as energy/fuel for the body, brain etc.?

    1. Hi Oliver and apologies for the very long delay responding. I think you might have misunderstood what I mean. We can burn dietary fat and body fat to produce energy but we do this converting fat into carbon dioxide and water. What we cannot do is convert the atoms in fat into pure energy. In other words, the number of atoms in the universe does not change when we burn fat. The atoms are, instead, simply rearranged to form different substances, ie, CO₂ and water. Energy is released but no atoms are converted into energy. I hope that clarifies things.

  11. Do you know whether it’s better to do long distance runs to breath more fat out, or shorter distances at a harder/faster pace so you breath deeper and harder. Is there a recommendation?

    1. Hi Richard, apologies for the very long delay replying to your question. The intensity and duration of physical activity combined will determine how much air you breathe in total. A short burst of high intensity activity can cause you to consume just as much oxygen, and exhale just as much carbon dioxide, as a longer bout of less intense activity. I am not an expert on the benefits of high intensity training. You will probably get difference recommendations from different trainers. It’s also risky to go from a low level of physical activity directly to high intensity activities but, again, I’m not qualified to give advice. I hope that helps.

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