When we heard that drinking water in the morning could boost your metabolism [1], we went to the experts to find out if this was true. Turns out it isn't true, due to the low thermic effect of water. So, naturally, when we heard that exercising first thing in the morning could boost your metabolism [2], we did what we do best: consulted an expert. To find out if this is just another metabolism-boosting myth, POPSUGAR spoke to Avigdor Arad, PhD, RDN, CDE, director of the Mount Sinai PhysioLab [3].
What Is Metabolism?
As a refresher, your metabolism is a complex process [4] that relates to how your body processes energy from proteins, fats, and sugars/carbohydrates and how it stores that energy. When you hear people talking about having a slow or fast metabolism [5], they simply mean their metabolic rate [6] — the amount of calories their body burns in a day.
Does the Time of Day You Work Out Boost Your Metabolism?
"If you're working out, it's going to increase your metabolism [8], meaning you're going to be burning more calories when you're working out and you're going to be burning more calories after the workout," Dr. Arad told POPSUGAR.
Doing styles of training that require more energy — such as sprinting [9], HIIT workouts [10], and weightlifting [11] — will help you burn more fat and calories. But as far as your metabolism is concerned, working out in the morning has no effect on your metabolic rate.
Post-workout, your body will increase oxygen consumption, and as a result, it's going to increase your metabolism — the amount of energy you produce. "It's important to know that the time of the exercise is not necessarily making the difference. If you exercise in the morning, if you exercise in the afternoon, if you exercise at night, it has a very similar effect," he explained.
But What About the Afterburn Effect?
Although exercise can boost your metabolism, one thing Dr. Arad made clear was: "People are burning much less energy after exercise [13] than they think." People speculate that the afterburn effect, aka EPOC [14] (excess postexercise oxygen consumption), lasts for up to 72 hours after exercising, but according to Dr. Arad, "That doesn't seem to be the case." As we stated earlier, you do burn more energy with exercise, but "most of the energy that you burn is during the exercise."
Because you don't burn that much after working out, Dr. Arad said, you "really should focus on the exercise and do an activity that really helps [you] burn a significant amount of calories and a significant amount of fats." You may be wondering what the best workout for burning fat [15] is, and the answer is . . . it depends. Yes, we know this is anticlimactic, but it's the truth. Everyone has a unique genetic makeup that will respond differently to workouts like HIIT and steady-state cardio [16].
If you are strength training, begin to incorporate compound exercises [17] into your workouts, as they work larger groups of muscle, eliciting a greater energy expenditure, and burn more fat and calories. If you're not sure where to begin, try this four-week strength-training workout plan [18].