Since Thanksgiving was declared an official national holiday in 1861, it's become as much associated with expressions of gratitude as it with the sharing of a traditional meal with family.

"Thanksgiving revolves around food, but truly taking back the holiday means focusing on the things you are grateful for, not the least of which is the food on your table every day of the year, even if it isn't perfect," Addie Broyles of the Austin-American Statesman wrote in a column last week reminding readers that "gratitude, not a perfect dinner, is the name of the Thanksgiving game."

But it turns out that focusing on what you're thankful for isn't just a tip to focus on what's important and make the holidays less stressful: it's a scientifically-proven life hack, year-round.

There's a growing body of serious research that expressing gratitude can really, concretely make your life better. The best part is, you don't even have do to any mental contortions to make sure you feel it — you can just go through the motions of acting as if you do.

The findings are dramatic. The practice of gratitude (which can truly be as simple as jotting down notes about what you're thankful for) has been called "velcro" for wellbeing and deemed "the new willpower." It might even make people like you. Hell, it might make you like you more.

Here's how it works:

Gratitude: "Velcro" for good health

Robert A. Emmons, a professor of psychology at the University of California at Davis, and author of the book Gratitude Works! A 21-Day Program for Creating Emotional Prosperity, says gratitude is a kind of "velcro." In other words, embrace it and better mental and physical health will stick.

In a 2003 study that Emmons co-authored, participants who wrote down things they were grateful for each day exercised more, had more energy, and reported less pain. They also slept an average of 30 minutes more each night. He's also found gratitude effectively increases happiness and reduces depression.

A 2012 study published in Personality and Individual Differences found that grateful people experience fewer aches and pains and they report feeling healthier than others.

To be clear, there's no evidence that keeping a gratitude journal will cure a serious illness. But when it comes to feeling well overall, it really seems to work.

Don't worry about actually feeling it. Just do it

A lot of the reports on gratitude studies — and there are many — don't make clear distinctions between the experiences of people who really feel gratitude, and people who do things that make them think about gratitude, or simply go through the motions of expressing gratitude. (People are working on this: Emmons writes on his website that one of the two main lines of inquiry that he's currently working on is "developing a measure to reliably assess individual differences in dispositional gratefulness.")

But it turns out that knowing for sure whether you really are grateful or how grateful you are doesn't make a huge difference when it comes to gratitude's positive effects. Whether it's a card to someone else, or a note to yourself about what you're grateful for, you can just write something down.

Really. Several studies have demonstrated that people who simply journal the good things that happened during the course of their days felt happier.

"It is helpful to remember that it's not really about feelings," Emmons said in an interview with Live Science. "Gratitude is a choice. We can choose to be grateful even when our emotions are steeped in hurt and resentment, or we would prefer our current life circumstances to be different."

It can make people feel warm and fuzzy about you

Saying thank you is a good way to make people like you. This is probably something you could have guessed, but now there's some research behind it.

The proof is in a 2014 Gonzaga University study that established an empirical connection between expressions of gratitude and the way people are perceived.

Study participants who were led to believe they were mentoring high school students later described the interaction in warmer terms - and were more likely to provide their personal contact information to their "mentee" - if they received a thank-you note for their help.

"Our study was the first to show evidence that yes, indeed, an expression of gratitude could help to initiate a new relationship," said Monica Bartlett, one of the authors of the study.

Plus, feeling gratitude just might lead you to do things that make you more inclined to connect with others. Emmons found that people who kept lists of things they were grateful for were more likely to report having helped someone with a personal problem or having offered emotional support to another.

Deemed "the new willpower," it just might make you more successful

A study conducted in 2014 by Northwestern University researchers looked into the effects of gratitude on "financial impatience" — basically, the opposite of an inclination toward delayed gratification. For example, one question required study subjects to choose between receiving $54 now or $80 in 30 days. But they did this after writing an event from their past that made them feel either grateful, happy, or neutral.

They found that those who'd described feeling grateful showed significantly more patience. "Even more telling was the fact that any given participant's degree of patience was directly related to the amount of gratitude he or she reported feeling," wrote David Destono, one of the researchers, in a Harvard Business Review piece describing the results.

That's what made them dub gratitude "the new willpower" and conclude that, like its emotional predecessor, it could be an important tool for success.

Of course, the long-term results of this tool remain to be seen. Still, the overwhelming evidence suggests that if you start practicing gratitude now, you'll have a lot more to be thankful for by next Thanksgiving.