You could, feasibly, work off a bad diet. Eat takeaways, fast food, and heaps of sugar, fat, and salt, then hit the gym… you might – might! – be able to maintain your fitness and keep a good physique.
However, it’s unlikely. It’s also unlikely that you’ll be very healthy as you do so.
Nevertheless, it’s still quite common to see. As a personal trainer, it’s common to find clients surprised when you get involved in their diet. ‘I thought you were just here for the exercise,’ they say. But, of course, you tell them no: the exercise is the least of it.
Diet is king.
The zero sum game
Don’t think of exercise as a way to ‘burn off’ fat or calories. You will be at it for a long time. An hour’s walk might have you burn off 300 calories. A gym session will see a little more. Two slices of pizza will negate this; a full pizza will put you in a serious caloric surplus.
It’s far easier to eat healthily to maintain your figure than to try to train it all off.
Now, don’t go thinking that it isn’t worth training if your diet is bad. You will still make fitness gains and improve your health. You will probably build muscle, improve your cardiovascular effectiveness and immune function, improve your circulation, calcify your bones, strengthen your joints, and enjoy the many mental health benefits afforded by exercise.
You will just probably also be putting on fat. At the very least, you won’t be making the most out of your hard work.
With a healthy diet – one rich in lean protein, healthy fat, complex carbs, plentiful and varied nutrients, and lots of fibre – you will build even more muscle.
Moreover, you will improve your cardiovascular effectiveness and immune function to a greater degree, you will enjoy far more energy, and you will be able to remain lean with a smaller amount of body fat.
There is more to it than simply balancing calories in versus calories out. Hormonal response is vital in maintaining healthy fat levels and building muscle.
What you eat can signal your hormones to burn fat or store, alter metabolism, and have an effect on muscle building. Everything becomes far more efficient on a healthy diet; it becomes far less efficient on a poor one.
For instance, the calories you get from leafy greens will be far different to the ones you get in fatty, sugary ice cream, far beyond their simple nutritional value.
For one thing, sugar levels matter. It spikes insulin levels, which leads to more of those calories being stored as fat. Leafy greens like kale, on the other hand, trigger hormones like glucagon to be released – this is insulin’s equal and opposite partner, which releases fat to burn as energy.
Food is a language. Different foods tell your body to do many different things. Going with a healthy diet will, in overly simplified terms, signal your body to be healthy – it will simultaneously provide the fuel and the trigger for a cascade of healthy mechanisms to kick into being.
The inverse is true – healthy food does the exact opposite, leaving you unhealthy.
The take home
This needn’t mean you need to swear off unhealthy food. Here, I’m counting anything containing refined sugar, excess amounts of fats – especially hydrogenated fats – and any dietary planning that skips good-quality protein sources. You can have that pizza. You can have that ice cream.
The key, as ever, and as with so many things in life, is, of course, moderation.
Eat 80% healthy – leafy greens, mixed, colorful fruits and vegetables, whole grains, healthy fats and oils, and plenty of high-quality protein sources like chicken, eggs and whey. Then make up the final 20% with whatever you want. It will balance out reasonably well and will cause a good enough hormonal response to gear you towards good health and decent fat burning potential.
Then get out there and exercise. This should be a given. You will gain all of the benefits of an active lifestyle whilst priming your body to make the most from them.