Fat oxidation & running
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I recently read a post on Dave MacLeod's blog that got me thinking. It seems to me there are a lot of MacLeod haters on MP, but I think I'll ask anyway. Anyway, in this post Dave implies that he normally runs BEFORE breakfast so as to "to get into fat oxidation quicker". I had never heard of this before, but a little googling seems to tell me this is a good way to burn more fat (this paper looks like it supports this idea). From the cited paper it looks like you also need to nail the intensity in order to get the maximum fat oxidation rate. |
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If you constantly eat a ton of carbs, then yes, it is better to run on an empty stomach. If you eat lower carbs than it doesn't matter as much. excessive carbohydrate consumtion causes an insulin release, and one of the primary functions of insulin is fat storage. Your body CANNOT burn fat in the presence of insulin. |
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The miltary, in boot camp we would always run and workout before breakfast, after 8 weeks almost everyone had lost a ton of excess body fat. |
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I'd be interested to see studies on this as well. It certainly makes sense theoretically especially doing so in the morning when your body is already in oxidation mode rather than eating and burning through that free glucose. Eric Carlos wrote:Your body CANNOT burn fat in the presence of insulin.While I agree with what you're getting at, fasting insulin levels are not normally zero, so it's really more of a gradient than an absolute. Our bodies typically use multiple energy systems simultaneously, simply shifting the rates at which each is utilized. This study mentions research confirming your thoughts though interestingly they note that (on animals) a "fed state" of high fat did not inhibit oxidation, rather increasing it. Neat! Again, makes sense that throwing carbs down the hatch would be the biggest inhibitor (which I think is what Eric was saying). |
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Stickygreens wrote:The miltary, in boot camp we would always run and workout before breakfast, after 8 weeks almost everyone had lost a ton of excess body fat.Isn't that kind of a given tho. But I do agree with a hard work out before eating much. In fact I prefer to get out and do a hard ride, don't run anymore, before eating much. I remember reading this guys, Lito Tejada Flores, book on XC skiing. There was something about caffeine aiding in burning fat. He recommended drinking a caffeinated drink before or during a race to add quick energy from fat. As to the rest it's over my head or interest at this time. Depending on the type of climbing of course, but I always felt a little fat in reserve was a good thing. |
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Kenny Clark wrote:Does anyone else systematically do this to burn fat more effectively? Anyone have any specific experience on this topic? Any research that refutes this idea?Mr. MacLeod is a climber not exercise physiologist. It is probably best to consult medical literature for the advice, and your posted link is a step in the right direction. Unfortunately you seem to lack reading comprehension to interpret research presented in the article correctly. It appears that you want to make the case for more effective fat oxidation fasting. The article you quoted does not investigate effects of fasting on oxidation, it examines effects of exercise intensity on fat oxidation. It presents results to demonstrate that fat oxidation rates positively correlate with the VO2max, and, of course, the exercise intensity. So, what to take out that article? I believe the following paragraph is what you are really interested in: "" wrote:The finding that at the same relative intensity trained individuals ( i.e. individuals with a higher VO2max ) have greater rates of fatty acid oxidation, can be explained by the fact that the trained individuals are exercising at a higher absolute work rateI suspect that the fasting phase was introduce to make sure that folks had their blood sugar at a certain level, even then there is a discussion on the effects of variation in diet on the results To recap - Fitter individuals will oxidize more fatty acids at ~65% Vo2max effort because they produce more power at that effort. Now, how does one increase VO2max? - I would suggest running a simple search, but IIRC exercise after fasting at 65% max effort is not it. |
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amarius wrote: Mr. MacLeod is a climber not exercise physiologist.Actually... "Dave has a BSc in Physiology & sports science and an MSc in Medicine & science in sport & exercise." - amazon.co.uk/Dave-MacLeod/e… |
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Actually... "Dave has a BSc in Physiology & sports science and an MSc in Medicine & science in sport & exercise." - amazon.co.uk/Dave-MacLeod/e… |
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Research pointers. |
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Take a look at CLA. It is a supplement that was developed to help the Canadian army train in cold temperatures, and then used by Austrailian distance swimmers to combat the effects of prolonged water emerson. Tests have shown that it will decrease body fat by 10% even in non active people due to its thermogenic properties. |
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Kevin Stricker wrote:Take a look at CLA. It is a supplement that was developed to help the Canadian army train in cold temperatures, and then used by Austrailian distance swimmers to combat the effects of prolonged water emerson. Tests have shown that it will decrease body fat by 10% even in non active people due to its thermogenic properties. Running on an empty stomach after a 8 hour fast is just foolish. It may help Dave loose a few pounds so he can send his latest project, but it is likely to lead to Metabolic Disorder if practiced for long periods. You are putting your body in a calorie deficient state, when you eat afterwards your body will have a huge insulin spike and convert most of the calories into fat. Plenty of studies have shown that fasting actually increases your bodies propensity to store fat. Eat small balanced meals, keep your glucose (and insulin) levels at a consistent low level and you will have a much better chance of loosing body fat.It really depends on WHAT you're eating...Also, if you've been running for awhile I think the insulin would direct some of those calories into the muscles cells to replenish glycogen. |
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This is true and does work IME. I subscribe to a form of the Paleo diet, where my diet and exercise regiment are intertwined. If you think about it from an evolutionary standpoint, humans had to chase down game before they could eat it. We had to walk through the forest to collect nuts and berries and what not. |
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i'm kind of rusty on the topic, but running on a super empty stomach doesn't sound fun. running on a full stomach sounds worse. i think man tends to complicate things a bit too much. |
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I get bad side stitches unless I run on a totally empty stomach, so I always run first thing in the morning before eating. I don't run very far (4 miles is my standard distance), but I've never had problems from low energy and it has never seemed to be burning muscle. |
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I think (as usual) the science is murky behind all this. One of the problems is that not all studies examine the same exercise intensity and duration, thus making them harder to compare. Stickygreens wrote:The miltary, in boot camp we would always run and workout before breakfast, after 8 weeks almost everyone had lost a ton of excess body fat.This would happen in your scenario regardless of "when" you did it. Kevin Stricker wrote:Take a look at CLA. ... Tests have shown that it will decrease body fat by 10% even in non active people due to its thermogenic properties.Actually I do not believe CLA has ever been substantiated to really be effective. Certainly the body fat loss claims have been over-hyped greatly. |
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Thanks, Kevin. I found a recent meta-analysis which analyzed 7 studies (which qualified out of 15 randomized controlled trials, although 4 of the 7 still had major methodology problems) and concluded CLA seemed to have a statistical significance in enhancing fat loss for a duration of 6 months or more, albeit it was a small amount of weight difference lost (2 lbs +/- 1?). |
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Actually the study I posted did in fact go into the levels of training for all of the groups(table 4). The most interesting thing is that those who received the higher dose (6.8g) CLA had a significant increase in training time over the other groups. As it was a double blind test of obese and overweight individuals the fact that those who took the higher dose were not only able to work out more but also had a significant increase in LBM and decrease in BFM does seem like a positive correlation to me. |
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CLA is a scam. Just like 99.999% of the 'fat loss' products out there. Waste your money on it if you want. |
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Dustin Drake wrote:CLA is a scam. Just like 99.999% of the 'fat loss' products out there. Waste your money on it if you want.Hey, thanks for you opinion. Without any research to back it up I would have to say you are talking out your butt, but that's par for the course here anyway right. I'm not saying it is some miracle drug, it is just a form of Fatty Acid after all. I don't take it personally (no problems with weight) but have researched it and know others who have had good results. So post up your findings... |
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"I get bad side stitches unless I run on a totally empty stomach" |