What your morning routine should look like, according to science

Many things naturally happen to our bodies when we wake up. We start pumping out the hormone cortisol, a sort of natural caffeine. Most people's cortisol levels peak sometime between 8:00 and 9:00 in the morning.

Instead of hopping aboard this wakefulness train, however, coffee consumed at this time may actually blunt cortisol's natural effects, according to Stephen Miller, a Ph.D. candidate at the Uniformed Services University of the Health Sciences in Bethesda, Maryland. Instead of caffeinating during this window, Miller recommends holding off for an hour after you awaken.

Research suggests that an early-morning workout on an empty stomach helps speed weight loss and boost energy levels by priming the body for an all-day fat burn. Exercising first thing in the morning may push the body to tap into its fat reserves for fuel instead of simply "burning off" the most recent snack or meal.

Plus, working out early could mean you get more sunlight, which is key to properly setting your body's internal circadian rhythm. In one study, people who basked in bright sunlight within two hours after waking were thinner and better able to manage their weight than those who didn't get any natural light, regardless of what they ate throughout the day. A morning walk or run outside can also help fight the winter blues during dark, cold days.

Any kind of exercise is a healthy way to start the day, but the type that offers the most benefits for your body and brain is aerobic exercise, or cardio.

"Aerobic exercise is the key for your head, just as it is for your heart," write the authors of an article in a Harvard Medical School blog called Mind and Mood.

Cardio is the closest thing to a miracle drug that we have. Studies suggest that running or swimming helps to lift your mood and clear the mind. It may even help protect from some of the cognitive decline that occurs with age. It also strengthens the heart and lungs and helps tone up muscles. So get moving — preferably for at least 45 minutes at a time.

If you normally eat breakfast, there are three key ingredients it should have: protein, fiber, and healthy fats. Most US breakfasts are lacking in all three. Instead, they're full of refined carbs, a type of unhealthy carbohydrate that gets rapidly turned into sugar in our bodies. Pancakes, bagels, muffins, and even cereal all fall into this category. Add juice to the mix and you've got a big dessert.

Instead, try a couple of eggs with a few avocado slices, or some Greek yogurt (the plain kind, since the flavored varieties can be high in sugar) with fruit and nuts. Both of these options will fill you up, help smooth out your digestion, and power up your muscles.

If you're looking to lose weight and other diets have failed you, you might want to try an eating plan known as intermittent fasting— after checking in with your doctor, of course. There are several versions of the diet, but one of the most popular involves fasting for 16 hours and eating for eight. Most people opt for an eating window of 12 p.m. to 8 p.m , meaning you essentially skip breakfast but eat whatever you want within the eight-hour "feeding" window.

Large studies have found intermittent fasting to be just as reliable for weight loss as traditional diets. And a few studies in animals suggest it could have other benefits, such as reducing the risk for certain cancers and even prolonging life — but those studies need to be repeated in humans.

The ingredients you're looking to get from a multivitamin are better processed by your body when they come from real food. If you're not eating right, taking a vitamin isn't going to do you much good anyway. For these and other reasons, experts are suggesting that people stop taking many vitamins and supplements, since they're part of a largely unregulated industry.

"Consumers should expect nothing from [supplements] because we don't have any clear evidence that they're beneficial," S. Bryn Austin, a professor of behavioral sciences at the Harvard T.H. Chan School of Public Health, told Business Insider. "They should be leery that they could be putting themselves at risk."