Thursday, April 24, 2014


In 2012 there was an interesting study done at the University of Copenhagen involving roughly 60 sedentary, overweight men. They were divided into three groups: a control group that remained sedentary; a group that did 30 minutes of cycling and running a day (enough to burn 300 calories); and a group that did 60 minutes of cycling and running a day (enough to burn 600 calories). The experiment lasted 13 weeks.

The amount of exercise each person got was well monitored (see the report if you want details about how this was done).  Anyone who wasn't complying was kicked out, those who did comply got paid. Compliance turned out to be 96-99%.

The results were very surprising.

The group who exercised for 30 minutes lost slightly more weight and the same amount of body fat (14%) as the 60 minute exercisers! The fat loss was more impressive than the weight loss and the researchers (and everyone else in the health field) wish that people weren't so weight obsessed since fat loss is really a lot more important for health and is actually what makes us look and feel better.

What the report doesn't say (because it wasn't part of the study), but one of the researchers told my Diabetes - a Global Challenge class, is that those in the 60 minute group didn't enjoy the study, whereas those in the 30 minute group were quite happy doing it.

How could both groups have similar weight and body fat reduction when one group was burning twice as many calories as the other?  Answer: The bodies of the 60 minute exercisers compensated. Different bodies compensate in different ways -- some bodies get lazy for the rest of the day, some bodies get hungrier than usual, some metabolisms slow down, and what some bodies do researchers have yet to figure out, but they do compensate to hold on to energy stores (fat) when over-stressed.

The bodies of the participants in the 30 minute group did not compensate. In fact those participants seemed to spend some additional energy the rest of the day just doing normal daily activities. In other words, they were energized by their exercise not tired-out by it. Plus their appetites were not over-stimulated.

The lesson here is that we have to measure the effects of an exercise routine over a 24 hour period and notice whether it's having a positive or negative effect on our hunger, our emotions, and our motivation to move. The correct amount of time spent exercising will be individual and it will change over time. But there is no point in overdoing it!

Read the whole study here:
Effect of Exercise on Energy Balance in Overweight Men

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