If you have wondered whether it’s best to exercise in a fasted state, before eating breakfast, or to eat breakfast and then have your workout session, I will weigh in here.
For years we have been told breakfast is the most important meal of the day and you must eat a good, nutritious breakfast in order to have the best exercise session. But is that really true? Here are a few benefits of exercising in a fasted state which just means, before you eat your breakfast or whatever your first meal of the day ends up being if you intermittently fast, as I do.
Fasted exercise improves levels of glucose and insulin, lowering risk of insulin resistance and Type 2 diabetes;
As I explain in Today is Still the Day, exercising in a fasted state is particularly effective for fat loss as it lowers both total body weight and body fat percentage. Exercising after eating only reduces body weight;
It curbs food intake for the remainder of the day, resulting in an overall energy deficit of about 400 calories;
It may boost growth hormone and production of testosterone, which prevents depression and optimizes tissue regeneration;
People who skipped breakfast and worked out on an empty stomach had better working memory in the mid-afternoon and reported less mental fatigue and tension later in the day than those who ate cereal before exercising.
It helps prevent depression.
Exercise and fasting together cause oxidative stress, which helps counteract muscle aging.
So I think it is safe to say if fat loss and improving muscle health is your primary goal, working out fasted would be the way to go.
Another huge bonus is that exercising while fasting for more than 14 to 18 hours (which you might do if you practice intermittent fasting) likely activates as much autophagy as if you were fasting for two to three days by increasing AMPK, NAD+ and inhibiting mTOR. Autophagy is the process whereby the body cleans out damaged cells, in order to regenerate newer, healthier cells. It occurs during prolonged fasting.
So should you never eat before exercising? It is not appropriate for everyone. It depends on your age, when you last ate, whether or not you’re pregnant, medication use, medical history, fitness level, whether or not you are metabolically flexible and the type of workout you engage in. If you feel weak, dizzy, nauseous or lightheaded, you probably should eat something before working out. I certainly wouldn’t recommend a bowl of cereal, by the way. A light protein meal like a small whey protein shake is a good choice.
As with all things, it is always best to listen to your body and use wisdom to find what works best for you.
Do you eat before you exercise or do you routinely exercise in a fasted state?