This morning I was nothing short of dumbfounded when I jumped on a set of scales and discovered I have gained weight. Inspired by the research I’ve been doing lately into the brain-health-exercise connection, I’ve been stepping up my usual workout routine a notch. I had assumed that a nice bi-product of my brain-boosting exertions would be a touch of weight loss. To my horror my efforts had the opposite effect. I was almost half a kilogram (roughly one pound) heavier than the previous week. Ouch. It prompted me to do a little digging into the latest research on exercise and weight loss and boy am I surprised by what I discovered.   It turns out I’m not alone in my exercise induced weight gain. A recent thought provoking study showed that an unfortunate group of 81 women who took up an exercise regimen for 12 weeks ended up heavier than they were at the start. While you might be assuming this is because the fledgling exercisers were losing weight but gaining muscle, that is not what the researchers found. The women were fitter, but fatter. Almost 70 per cent of the women got fatter, and one had gained as much as 4.8 kilograms (10 pounds).  

The study wasn’t a one off either. A recent review of research looking at exercise and weight loss found that on average people generally lose only a modest amount of weight and far less than what is expected when they start exercising more. The reason, researchers believe, is that when people start exercising, they compensate for their extra activity by unconsciously eating more and moving less. The natural conclusion being drawn is that exercise alone isn’t enough to induce weight loss.  

When I started thinking about my previous week, I realized I’ve been allowing myself a few extra treats. In my mind, all that additional energy I burned meant I deserved them, right? Then it hit me. My mind may have been playing a game of subterfuge, undoing all the good I’ve been doing at the gym.  

This line of thinking lead me to the fascinating work being done at the Cornell University Food and Brand Lab, which is dedicated to trying to understand why we eat what we eat and how triggers around us - such family and friends, packages and plates, names and numbers, labels and lights – can unconsciously influence what we put into our mouths. Brian Wansink and his team at the lab have found that exercisers frequently reward themselves with food before or after exercise. They justify their indulgent eating by thinking things like “I can eat this piece of cake because I will exercise later today.” As one researcher points out, the benefits of exercise can be wiped out in minutes by the consumption of high-energy foods.  

All this is not to say that these food rewards will automatically lead to weight gain. The key is to keep energy expenditure and energy intake in balance. Unfortunately Wansink’s research has shown that this far more difficult than it sounds. It turns out, we are terrible at estimating how much we have eaten.  

In one study where he had people eat tomato soup out of a bowl that was secretly refilling itself, people consumed a whopping 73% more than people eating out of a regular soup bowl. The real blow was that despite consuming all that extra soup, they didn’t know it and they didn’t report feeling more full than those eating from normal bowls.  

Most of this happens at a subconscious level and the science of ‘mindless eating’ is one I’m looking forward exploring more in future blog posts. In the meantime, I’ll finish with some good news coming out of the Food and Brand Lab. If you think of your workout as a “fun run” or as a well-deserved break, you’ll eat less afterward. 

In one study people were led on a two-kilometre walk around a small lake and were either told it was going to be an exercise walk or a scenic walk. Those who believed they had been on an exercise walk ate 35% more chocolate pudding for dessert than those who believed they had been on a scenic walk. The researchers conclude that if you’re considering starting an exercise routine in order to help lose weight, make sure you reframe it so you see it as fun—or at least not as work or exercise. They suggest listening to music during a run, making phone calls during a walk, or watching a video during a treadmill routine.  

As for my own exercise efforts this week, I'm aware that there are a number of reasons that could explain my weight fluctuations and I'm not too worried. But I’ll be a little more conscious of what I’m putting into my mouth and looking for ways I can trick myself into mindlessly eating better. If you have any tips or tricks you use, I’d love to read them in the comments below.