Whether your interest in fitness revolves around weight loss or athletic performance, you’ve likely given a considerable amount of thought to the function of your metabolism. After all, this complex system controls exactly how your body uses the energy derived from your food – which includes the amount of fat and muscle tissue attached to your frame.

A frequent topic for discussion, then, involves how to keep your metabolism optimized and burning calories quickly. Unfortunately, a lot of the information out there is based on outdated or misinterpreted science.

To help clarify things a little, here are three common practices that – according to the most up-to-date research – definitely slow down your metabolism.

Get Enough of Sleep

Getting your full eight hours of sleep each night can be a real challenge. You might be dealing with work, family responsibilities, or any number of other demands that can keep you up. Occasionally, well-meaning individuals even cut back on sleep as a way to give themselves more time to exercise.

Unfortunately, this practice is entirely counterproductive. According to an ever-growing body of research, inadequate or low-quality sleep can greatly contribute to your risk of developing obesity and type II diabetes.

While the exact mechanisms at work here have yet to be fully understood, the prevailing theory is that a lack of sleep doesn’t allow your body to fully recover from the challenges of the previous day. Part of this recovery includes the allocation of nutrients and balancing of hormone levels. If this doesn’t happen properly, all sorts of problems can arise.

Additionally, a lack of sleep can cause your brain to assume that something is terribly wrong. After all, something is keeping you awake. As a result, levels of the stress hormone cortisol tend to remain elevated above healthy levels. Along with encouraging fat storage and slowing your metabolism, high levels of cortisol also contribute to mental fog, depression, and a lack of energy.

Limit Your Cardio Workout

Typically, when people want to lose weight, they immediately jump on the nearest treadmill and start cranking out endless hours of cardio. This, as it turns out is usually not the best strategy.

Moderate-intensity cardiovascular workouts of more than 20 minutes or so could actually work against your weight-loss efforts in several ways. For one thing, this style of exercise causes a spike in our old friend – cortisol. As mentioned, this hormone makes your body hold on to fat and even add more to the stored up tissue.

Unfortunately, cortisol also makes your body turn on muscle for fuel. Which can have numerous ill-effects. Specifically, this can negatively impact your metabolism in surprising ways. But more on that in the next section.

For now, it’s important to understand that prolonged cardio also causes changes in the levels of other hormones – ultimately creating an environment in which your body holds on to fat instead of getting rid of it.

Avoiding Weight Lifting

While people are devoting all sorts of time to cardio, they also tend to neglect weight training. In fact, many individuals do this on purpose, believing that lifting will actually make them gain weight or get bulky.

Put simply: That’s not how this works.

Complicated a little bit: Gaining weight – of either fat or muscle – requires you to eat excess calories. So, if your diet doesn’t allow for you to add extra mass, it’s not going to happen. Regardless of your workout style.

So, then, what’s the point of lifting for weight loss? Unlike fat, muscle actively burns calories. Even when you’re sleeping. The more muscle you have, then, the more calories you will use when at rest.