I really like Lon Kilgore. I wish there were a lot more Lon Kilgores in the world and a lot less Les Mills instructors. Lon is clearly very intelligent and has a great deal of knowledge to share with the fitness community. Importantly, Lon is willing to incorporate information from the real world into his theoretical assumptions. Here is an excerpt from a recent article that Lon wrote for the CrossFit journal …
“To the objective observer, it should be fairly obvious that CrossFit methods of fitness training are proving themselves in the field. Out in the real world, the average Joe who sees results like those typically seen by their CrossFitting friends are swayed by success. This is why the CrossFit community is growing and thriving. But there is always a cadre of exercise scientists and physicians who don’t necessarily believe results from the field (after all, “there were no controls”). There is an adage in the sciences that “you can prove anything with a single case example,” so anecdotal reports of success from the field are frequently assigned a merit and validity best suited for File 13 or Area 51. If the testing didn’t happen in a controlled laboratory environment, the thinking goes, the results cannot be the product of an evidence-based system and therefore must be the worst kind of popular and faddish trash or fiction.”
Field evidence is very important. In essence it is what stops us from taking a little bit of laboratory knowledge and falling on our face trying to explain things that should not occur in the real world but clearly do. The world is a frustrating place like that. No matter how much you think you have it pinned by thinking about it, sometimes it just doesn’t work the way you expect, regardless of how many lab tests you do.
I recently read the following in a self-proclaimed leading Australian fitness publication …
“With high-intensity exercise, while the overall energy expenditure is high, it is physiologically impossible to burn large amounts of fat. The major fuel for this type of exercise is carbohydrate and fat use is extremely minimal” … the article went on to advise me that …”The ideal fat-burning (intensity) varies from person to person - I usually suggest that it is the level of intensity where you can just hold down a conversation” and that the real problem is that “the majority of us will cap our exercise time off at 60 minutes”. The author holds a Masters of Science in Human Nutrition. The article is not referenced, but no doubt there are behind it a collection of lab experiments that indicate that as exercise duration increases more and more body fat is burnt as a fuel source. Ignoring the field evidence, the assumption that high intensity or short duration exercise therefore will not reduce body fat seems logical. Right?
So, given that my average workout time is about 12 minutes/day and ranges from 3 minutes to 25 minutes about 6 days a week, and that I eat a busload of calories every day (about 3600-4000), and that I train at the highest intensity (that I have the motivation to muster), then it is obvious that I am fat, because it is “physiologically impossible” for me to burn fat. And of course, the same applies to every other serious CrossFitter on the planet. We are all fat!
Sarcasm aside, field evidence suggests something different. The harder we train, the leaner we get. CrossFitters are lean. Why? Because we eat less carbohydrate, train more intensely, use more functional movements, and varify the stimulus more often than people who aren’t lean. What happens if we eat more carb, train longer at lower intensity? What happens if we start training at an intensity where we can hold conversation? We get fatter than we are now!
Concluding that high intensity exercise in short duration doses does not burn fat because carb is the predominate fuel source is using knowledge to be stupid and is ignoring evidence from the field. An exercise session that is low intensity and longer than an hour does not produce a systemic response, ie the stimulus is not significant in order to bring about systemic change. To place the body under stress and therefore stimulate an adaptation, you need to go much much longer (in this regard the lab knowledge led to the right conclusion) OR much much harder (the better and more time efficient option) ala CrossFit. Just because mid-intensity mid-duration exercise (60 mins of conversation time) does not alter fat composition does not mean that high-intensity short-duration exercise (10 mins CrossFit /cannot talk nor breathe) can’t. If something is brown, smelly and found in the toilet, I am not going to believe that it is mud no matter how compelling the lab results. Field data and experience tells me otherwise. High intensity short duration exercise is the most effective pathway to dropping bodyfat. Here is a picture of one of the CrossFit HQ lab results …
