The topic of exercise and fat loss is/has been an interesting one. It is a bit counter intuitive that exercise may not be of primary importance when we look at leanness or more specifically, inducing leanness in otherwise overweight individuals. It is a minority view that insulin signalling is more important in leanness than total caloric content or energy expenditure due to activity…but I’m pretty sure that is indeed that case. I really hope the irony of this statement sinks in considering I make my living putting people through workouts!
So can we hang up the O-lifting shoes and swear off Tabata sprints? Can we say good bye to hard exercise and just rely on low carb eating for all our health and lifestyle needs? No, not if we want to be healthy and vital.
Things get murky when we equate leanness with health. The two are correlated but there are points of deviation. In the case of leanness and insulin signaling we have some parameters our genes are born into this world expecting to encounter. Distributed throughout the population are variations that allow for greater or less adaptability to environmental cues such as food (particularly high insulin releasing food) and sleep deprivation. High glycemic load foods and sleep deprivation both induce insulin resistance but some people handle these situations better than others.
What does this have to do with exercise? We are not only born into this world with genes wired for certain types and ratios of foods but our genes are also best expressed when we are active. VERY active. Why? Lets, take a look at gene expression and epigenics to better understand this.
In simple terms, sections of our DNA, called genes, code the proteins that make up our hair, skin, immune cells, hormones and really everything that makes us, “US”. For many years it was assumed that genes function via a simple on/off mechanism, however the story is a bit more complex than that. Environmental cues ranging from food to sunlight to exercise can influence the frequency with wich genes are expressed and taken in total this can have profound influence on our health. If you follow Art Devany’s blog you might recall the “Twins” post he had some time ago. This is a stunning demonstration of virtually identical genes expressed in remarkably different ways due to environmental cues, in this case long distance running vs. track and field training. Many of you may be familiar with the following paper but I think it is important to dredge up some older goodies from time to time and I also wanted to put some importance back into exercise since we’ve been picking on it recently with our look at leanness. I consider this paper from Booth to be absolutely foundational in its proposition that we need to look at the environment under which our genome was formed for clues as to why many of our modern diseases occur. When I first read this paper I made the observation “If you are not exercising you are broken”.
In some ways all of this is complex and paradoxical. We can be lean and exercise, all the while we are sick due to high glycemic foods. Similarly we can be overweight, yet we will improve our health to some degree if we exercise. It’s tough to make a sound bite from this but it might look something like “For leanness eat a low glycemic load diet built around lean proteins and seasonal vegetables and fruits. For health and vitality exercise most days with varying intensities and activities”. Like I said, it sux for a sound bit.