How much fat do I burn?

Hello everyone, a while ago I posted a video of me doing a VO2 max test. I was finally able to go through the data and today I am presenting my FatMax results that came out of the VO2 max test. First I want to do a quick refresh of the concept of respiratory coefficient or RQ. Because we measure oxygen consumed and CO2 released during the test, we can determine how much sugar (glucose) and fat is used under resting and exercising conditions. The RQ is determined by dividing VCO2 by VO2 (VCO2/VO2). When the RQ = 1, it means that glucose contributes 100% of the fuel used during exercise. When the RQ = 0.7, it means that fat contributes 100% of the fuel used during exercise. Anything between 0.7 and 1 represents a mixture of glucose and fat. Under resting and low intensity exercise the RQ should be closer to 0.7 meaning that more fat is being used for fuel. If the intensity of exercise increases, then the RQ increases and when glucose and fat contribute equally to energy production (50%/50%) the RQ = 0.85, and this is called the crossover point, which normally occurs at approximately 70% of the VO2 max. The other thing that can be determined is the FatMax or the point at which the maximal rate of fat oxidation occurs. The classical view based on evidence is that FatMax is achieved at approximately 60 to 65% of VO2Max and that at any exercise intensity above 85% of VO2 max fat oxidation is zero. Also, it has been shown that endurance trained athletes have a FatMax ranging from 0.5 to 0.6 g of fat per min. So how do I fit in this context? In other words, how much fat do I use during exercise. This is of particular relevance to me because since 2018 I have been on a low-carbohydrate diet and also doing all my training sessions under fasting conditions. The idea was to force my body to use fat for fuel and spare glycogen. The graph shows my FatMax fat in g/min in the y axis as a function of exercise intensity (% of VO2 max on the x axis). I was delighted to find that I spend mostly fat for fuel during resting and exercise. In fact, my lowest rate of fat oxidation (0.53 g/min at 25% of VO2 max) is what most people have as the highest rate of fat consumption when trained. My FatMax was equal to 1.61 g/min, which is more than 3 times the average, and was achieved at 77.5% of VO2max. From this point on, the rate of fat oxidation progressively reduced. However, I was surprised to learn that even very close to my VO2 max (98%) I was still using 0.69 g of fat per min. Then, my next question was: how do I compare with endurance athletes either on a high-carb/low-fat and low-carb/high-fat diets? Here you go: In blue, are data from two studies reporting FatMax values for athletes on a HCLF diet. In red, are data from two studies reporting FatMax data from athletes on a LCHF diet. In green in my data. As you can see, My numbers are well within the values of endurance athletes adapted to a LCHF diet and my FatMax was actually slightly higher than the average and remained elevated even longer.
In summary, this is proof that you can manipulate your metabolism through diet and exercise to enhance the ability of your body to use fat for fuel. This can be very good to keep your body fat percentage reduced and within a healthy range. By the way, my body fat percentage ranges between 10 and 12%. Also, if you are an endurance athlete looking for ways to spare glycogen and minimize the negative impact of glycogen depletion during endurance events, it might be worth considering a low-carb diet and conduct your training sessions under fasting conditions. There is a lot more to talk about my VO2 Max test data, but I will present in future videos. Thanks for watching and leave your comments below. I’ll see you in the next.

[@luckypotions]

I have never been more interested about this topic, you just explain it perfectly 😭 also this is completely unrelated, but your voice is so soothing!!

[@glenkatsnelson2549]

Very impressive results, this is my second time watching the video

[@rolandoceddia9061]

Hi Glen, good to see you here. It's been a while since we spoke. This test allowed me to assess how fat adapted I am after all these years on a low-fat diet. How is med school going?
Best, Rolando

[@glenkatsnelson2549]

​@@rolandoceddia9061 it's good to see you too, yes the results are very motivating. Things are going well and I hope to go into anesthesiology. How is everything at the lab? I have been following along with all the papers.

[@hh-nx8ku]

interesting hmmmmm

[@Artex123]

Hi! Hope you are doing well. I miss Joana, just want to know.. how is she?

[@rolandoceddia9061]

She is doing fine and focusing on school work.

[@valy_c]

great vid! Tell Joana we miss her a ton and are happy she’s doing well! She left a great impact on so many people 🫶🏼