As the new year is upon us, many people reading this will have made the new year’s resolution to eat healthier and lose weight. The basic plan of eating less and moving more is usually embarked upon but often people will incorporate too much training too soon, which can lead to burnout, injury or overtraining that will ultimately prevent you from reaching your goal.
As a personal trainer with over a decade of experience working with clients, I have been fascinated by the cognitive mechanisms and underlying dietary behaviours and the role exercise plays in helping people improve their diet for the entirety of my career.
The saying that you can’t out train a bad diet is fundamentally true. As Nic mentioned in one of his talks during his lockdown seminars, people are very good at conserving energy and will often account for the calories burned during exercise by consuming more calories later in the day or by being less physically active throughout the rest of the day – or even worse, a combination of both!
So, with that being said, it may beg the question – why exercise at all? You can – and absolutely should – use exercise to be a part of your weight loss effort, but not to attempt to offset calories consumed.
If your goal is weight loss, the only way to achieve this is by creating a calorie deficit and primarily controlling your calorie intake. The easiest way to do that is to limit the consumption of junk foods, namely highly processed foods like takeaways, cakes, chips, and cookies. Even if weight loss isn’t your primary goal, limiting the intake of these foods is ideal for physical and mental health.
Using regular exercise to improve brain function and cognitive processes is a far better approach than try to ‘burn off’ all the poor food choices you may make. If you’ve ever looked at the illustrations of how many minutes of exercise it takes to burn off certain foods, you’ll realise this approach isn’t a fair fight…Exercise helps to create a sharper mindset and increased willpower as well as reducing stress, which will help you to make better food choices.
Why do we overeat? I’m sure everyone reading this knows that they shouldn’t be overconsuming chocolate, ice cream, pastries, cakes, sugary drinks, and desserts. We all know eating this food leads to quick weight gain, yet I’m sure we all find these foods equally hard to resist. Ultra-processed foods have been designed, often with incredibly smart and well-paid food scientists to be as delicious and addictive as possible. One brazen chip company even ran a successful ad campaign with the slogan ‘bet you can’t eat just one”. Highly processed foods trigger dopamine and rewards centres in the brain and lead to cravings and a drive to eat, even when we aren’t hungry.
So how can exercise help? A region in the prefrontal cortex of the brain can help with the consumption of processed foods by both decreasing the activity in the reward centres and by initiating the cognitive processes needed to exert conscious control over the cravings. Neuroscientists have shown through brain imaging that increased activity helps to control food cravings by decreasing the activity in the reward centres. Conversely, when activity is decreased, the same region in the brain slows down and we have a harder time resisting temptation.
Exercise can also help regulate food consumption by boosting brain plasticity, which is the brains’ ability to adapt its function based on new inputs and stimuli. Boosting brain plasticity makes adopting and sticking to new habits easier – which is inherently what is involved in successful weight loss attempts. After all, you are what you repeatedly do.
These exercise-induced increases in brain function and cognition makes it easier to regulate or limit our consumption of junk foods. And we can see the effects with as little as 20 minutes of moderate intensity exercise. The key takeaway here is that regular exercise can reduce how much you crave bad foods and improves your ability to resist the temptation of these appealing foods by improving brain function and cognition. This makes it easier to limit the consumption of these foods to achieve healthier eating and weight loss goals.
Exercise also helps reduce stress. When you’re stressed, the body releases a hormone called cortisol, which activates what is known as the fight-or-flight response. The stress response is an important evolutionary feature that helped humans survive the litany of genuine threats that used to exist. Nowadays however we live a lifestyle that has us constantly stressed – we are bombarded with highly busy jobs, being constantly available and even a pandemic just for good measure. When cortisol levels are high, the brain thinks it needs more fuel, resulting in increased cravings for sugary or salty ultra-processed foods. Participation in regular exercise or a single bout of exercise reduces perceived stress levels and cortisol levels. Exercise also helps reduce unhealthy drink and food consumption when you are stressed.
So then, what exercise is best? I’ve been asked that countless times over my career and the answer is the best exercise is one you enjoy and can sustain over time. Running, walking, cycling, swimming, yoga, and strength training are all effective in helping improve diet by targeting prefrontal brain function and reducing stress. If you are beginning a new exercise routine this new year, ease into it, be kind to yourself, listen to your body and remember that a little goes a long way.