Picture this: You’re on a health kick. You’ve started the keto diet and you’ve lost a couple of kilos. Woohoo! But all of a sudden you’re usual morning jog or spin class has turned into an absolute punish. What’s the catch?
Here’s a quick nutrition lesson. Your body gets energy from three macronutrients: carbohydrate, fat and protein. It is engineered to use carbohydrate as its preferred source of fuel – especially when it comes to exercise.
When you eat carbs (read: grains, legumes, dairy, fruit and starchy veg), they are broken down into glucose (i.e. sugar) which enters your bloodstream. If you’re exercising, your body automatically uses that sugar for energy first, and it will then turn to the stored glucose (i.e. glycogen) in your liver and muscles. After that, it will turn to fat, but you might be surprised to learn that fat can’t be used for fuel as quickly as carbohydrate can – so relying on fat can impair your stamina, physical performance and recovery.
For the average Joe, the best way to fuel your body for exercise is to have a diet rich in low GI carbs (i.e. slow burning carbs that give you a steady stream of energy). If you need it, a higher GI snack just before exercise could be useful, and post-exercise, you want a combo of carbohydrate and protein to recover most efficiency.
The bigger picture
Yes, the ketogenic diet can help with quick short-term weight loss, and yes, exercise is key for weight management. But crossing the two isn’t always the easiest – and there are much more important things to consider.
As a dietitian, my main gripes with the ketogenic diet relate to the potential nutrient deficiencies that can arise from eliminating so many foods. Fibre is one of them – and while non-starchy veg, some fruits, nuts and seeds are allowed, it would be super tough to get enough sans carb-rich wholegrains and legumes. Another thing to consider is the range of micronutrients you’re wiping off your plate by cutting out so many foods, like energising iron or bone-strengthening calcium, for example.
On a similar note, exercise does so much more than just help you burn calories. It should be thought of as a necessary daily activity, like brushing your teeth, rather than a punishment for eating food.
Some ketogenic blogs go so far to say you don’t even need to exercise, but I beg to differ when it comes to your long term health. Aside from helping with weight management, regular exercise reduces your risk of diseases like type two diabetes, osteoporosis and some cancers, can help with stress management and even improve your sleep.
Overall, what I think is important is finding a balanced approach to eating that fuels your body well and compliments your tastes, preferences, lifestyle and budget. Pair that with regular exercise that you enjoy and activities to nurture your mental health, and you’ll have a much more sustainable lifestyle than a quick fix low carb diet that leaves you running on empty.
Melissa Meier is an online and Sydney-based Accredited Practising Dietitian. You can connect with her at www.honestnutrition.com.au or on Instagram @honest_nutrition.