Kananaskis Dispatch

By Dr. Tanya Berry, Alberta Centre for Active Living

With a title like that you’re probably expecting a blog about majestic mountains and the motivational power of wilderness for physical activity. You’re looking forward to hearing about people striding about in hiking boots exhilarated by the fresh air and close encounters with a bear. You hope such tales will inspire you to leap into the great outdoors.

Nope.

Today I’m going to write about how easy it is to make rats fat.
I am writing this from Kananaskis, Alberta (hence the title), and I’m here for the Western Obesity Summit, which is a multidisciplinary forum for obesity researchers. I wasn’t here to present, just to learn, and what I’ve learned is that if you restrict calories, you can slow down aging in rats. I’ve also found out that there is some sort of link between obesity and immune function in rats.

Further, did you know that if you feed rats high-fat, high-sugar diets, their bones break more easily? And I can now also tell you that some kinds of gut hormones in rats are related to how much they eat. I think.

I think that’s what I’ve learned, because, in all honesty, this has been a hard slog for a psychologist. Not the fault of the researchers, but to quote Dr. Seuss, I puzzled until my puzzler was sore trying to make out some of those slides. But, try as I might I couldn’t get further than what I’ve already told you, and don’t quote me because I’m not entirely sure that I got that right.

I was inspired to write about this, because such research sometimes get filtered through to the general public. As a result, some people change their whole lives, believing, for example, that if you don’t eat very much you’ll live longer. In fact, there’s a whole society dedicated to this (http://www.calorierestriction.org./).

The problem of course is that these are rat studies, not human studies, and that these are very specific rats. The rats used for these studies have a genotype that makes them very easy to make fat and are therefore very specifically chosen by obesity researchers for their studies. (Thanks to my colleague who explained that one to me.)

Indeed, when I went to the calorie restriction website, they had the results of a restricted-calorie mouse model study featured on their homepage as evidence for why you too should skip the chocolate and everything else.

It’s a very dangerous leap from mice to humans. I strategically sat beside a physiologist colleague, so that I could pester him with questions. He told me that there is a classic case of a substance that you inject in a rat and they lose weight. If you inject a human with the same substance, nothing happens. It might come as a surprise to some, but humans are different than rats.

This, I would like to repeat, is not because researchers are making the leap. I think the problem is that as a society we are hungry for solutions. The search for the fountain of youth is not over. So, we see a possibility, and we lunge at it.

It may very well be that humans will live longer if they eat less, but how much less? And for how long? Is there a critical age during which it’s best to restrict your calories? Too many unanswered questions for me. And so I applaud my colleagues for their work and hope they continue. But for everybody else who doesn’t do this kind of research: beware of basic experimental research that is interpreted as applied.

Now I’m off for a hike in the mountains.