New Year's resolutions you should make based on science - and how to keep them

Recent research shows that getting enough sleep makes it easier to avoid cravings for unhealthy foods, keep off excess weight, and that it's key for psychological health.

In the long run, sleep could be even more important: in several studies published in the summer of 2017, researchers demonstrated that after disrupted sleep, individuals had higher levels of proteins associated with Alzheimer's and dementia in the brain.

And as sleep expert Matthew Walker, author of the new book, "Why We Sleep," recently told Business Insider, you really can't get by on six or seven hours of sleep — the vast majority of people need an average of eight hours a night.

To improve your sleep, experts recommend going to bed and getting up at the same time every night, improving your sleep environment, and avoiding screens for at least a half hour before bed, if not longer. If you're struggling with insomnia, there are science-backed tips for that too.

Yes, exercise resolutions are common, but there's a good reason for them. Along with fixing your sleep, there's little that will have such a transformative effect on your life.

Exercise provides such a laundry list of physical and mental health benefits that it's basically the closest thing we have to a wonder drug.

Not only will exercise do everything from improve your heart health to boost your sex drive, all while improving your sleep and mood, recent research has shown that working out may help keep the brain young, improve memory, and fight cognitive impairment.

The trick is figuring out the exercise resolution that's going to work for you — saying you'll "go to the gym (more)" probably won't cut it.

Morning workouts aren't for everyone, but experts say that if you can get some morning exercise in that'll get your heart going and get you some morning sunlight, that'll kickstart your circadian rhythm, which will both wake you up for the day and make it easier for you to sleep at night.

Getting a good amount of cardio exercise seems to be strongly linked to many of the biggest benefits of exercise, and if you can do this in the morning, there's recent research suggesting that morning is best time of day to work out to lose weight.

To provide motivation to follow-through with your morning run, swim, or ride, experts suggest working towards a goal (like a race) so you have a concrete objective, training with a friend, and making it competitive.

But if you really hate the morning or simply don't have time then, don't make a resolution you know you won't keep. There's a reason why approximately 60% of gym memberships people start in January never get used — they're started by people with good intentions but who don't really enjoy making gym visits a part of their life.

Experts recommend finding an activity that you like enough to make it part of your life.

For some people, that might be rock climbing, for others, running or swimming. Join a soccer league if you miss running around on the field — the team element and competition involved will make you stick with workouts week-in and week-out, which is what you need to actually keep up with your resolution.

There's an abundance of recent research supporting the idea that if you were to try to cut back on one popular ingredient, it should probably be sugar — and not fat, as many used to think.

Sugar consumption is more strongly linked than fat consumption to heart disease and overall risk of death, one major analysis published last August reported.

If you want an official "diet" that's highly praised by researchers, you could take a look at the DASH diet, which has dieters cut sodium levels and switch from sugary foods and red meats to whole grains, lean proteins, and produce.

But an even simpler approach that many experts favor is just eating "real food," meaning nothing processed or preserved, and usually avoiding anything pre-prepared.

For a resolution to eat healthier, try to resolve to cook a meal using no pre-prepared ingredients at least once more per week at home.

A healthy resolution might be to cut back or eliminate sodas or other sugary beverages from your diet. Much of the average person's sugar intake comes from what they drink, and we continue to find reasons for why sugar is bad for us. Just recently, scientists revealed in a new study how data indicating that sugar consumption increased risks for cancer and heart disease had been hidden from the public for decades.

When it comes to booze, moderation is the safest best. There are recent studies indicating that some regular alcohol consumption is linked with lower risk for diabetes or cognitive decline. But any amount of alcohol likely increases cancer risk, so a resolution limiting your consumption might be a good idea.

One thing you don't have to worry about drinking less of is coffee, which in many ways is associated with better health or a longer life (but avoid those sugar-packed coffee drinks!).

Contrary to what the workaholics of the world might have us believe, humans have limits.

There are certain times when we might be able to grind away at a project for hour after hour, but we can't do that all the time.

In fact, psychologist K. Anders Ericsson told Business Insider that for the most part, we can only engage in heavy mental work for four or five hours at a time — not eight or ten or twelve.

In their book "Peak Performance: Elevate your Game, Avoid Burnout and Thrive with the New Science of Success", published this year, performance experts Brad Stulberg and Steve Magness wrote that most people who want to be more productive at work should learn to take breaks.

In the short term, that means when your energy is running low you should get up and go for a walk or do something else to really give your mind a rest. In the longer term, if it's possible, research indicates you might be best off setting yourself up to work fewer hours every week.

There's psychological evidence that reading — perhaps especially literary fiction — can make it easier to empathize with others or to imagine other lives in the world.

Luminaries of the tech and finance worlds like Bill Gates, Mark Zuckerberg, and Warren Buffett agree, often attributing much of their success to regular reading habits.

And reading is simply fun, a great way to pass the time and take a little break from the internet-connected world.

Pick a goal — a book a month or one per week, depending on what you normally read. Create or join a book club if the added motivation of chatting with friends (and snacks and drinks) will ensure you remember to turn the pages. Enjoy.

It can seem like we all have a million tasks to complete and needs to meet, leaving little time for relaxation. And while it's important to meet our necessities, there's a significant amount of psychological research that indicates that people who have more time and who make decisions that prioritize time over money are happier.

In one recent study published in the summer of 2017, people found that spending money on a time-saving purchase instead of an item provided a small but significant happiness boost. That corresponds with a growing body of existing research.

In a 2017 TED Talk, psychologist Adam Alter explained one of the reasons we feel like we have so little free time these days. We spend many of precious free minutes flicking through our smartphones, absorbed in the minutae of the internet but not engaged in anything longer lasting. Give yourself your free time back — and use it to cook a meal, get in a workout, or do some reading. It'll be one step towards a better 2018.