If you know me, you know that the phrase “I can’t” simply isn’t in my vocabulary. Tell me that a goal I’m reaching for isn’t achievable, and I just get even more pig-headed about achieving it.

Why? Because I’ve seen hundreds of miracles happen when people say these two magic words: “I can.” And I also see people give up on easily reachable goals because they limit themselves by thinking: “I can’t.” So I firmly believe in the power of “I can.”

And you know what? I have the science to back me up!

In a new study, researchers report that people who think their weight is outside of their control have higher body mass indexes (BMIs), make worse food choices, and report lower levels of personal wellbeing than people who think they can take charge of their weight.

The researchers say that the people who believe they were “born to be fat” tend to eat more frozen foods, restaurant meals, and ready-to-eat foods as they age. They also exercise less and pay less attention to nutrition labels on foods.

So guess what: The phrase “I can’t” becomes a self-fulfilling prophecy for these people. They get fat, old, and sick.

Now, let’s compare these people to some people who say “I can” when it comes to achieving awesome goals. For instance, have you heard of Ernestine Shepherd? She’s the world’s oldest competitive female body builder, and at 77 years of age, she’s freaking awesome. Here’s a video of her.

And if you think that she’s just a fluke, check out Willie Murphy,  Harry Packer, and dozens of other men and women whose YouTube videos are proving that something we once thought was impossible—having a young, strong, gorgeous body when you’re in your seventies—is doable.

What’s my message here? That if you say “I can’t,” you’re likely to fail at even the simplest of goals, like eating healthy food and getting a little exercise. But if you say “I can,” you can often achieve the impossible.

Now, I’m not saying that believing “I can” will make any dream you have magically come true. For instance, while I’m all about transformation, I don’t think I could transform myself into an Olympic gymnast or a pro basketball player.

But if a goal you really want to achieve is reachable—even if reaching it takes everything you’ve got, and maybe a little bit more—then I say, go for it. Be pig-headed. Don’t listen to people who say, “You can’t.” Believe that you can lose weight. Believe that you can get healthy. Believe that you can take years off your age. Believe that you can reach for the stars.

And believe that you’re awesome… because you are!

Keep Thinking Big & Living Bold!