(NewsNation) —Among the top five New Year’s resolutions are exercising more and quitting smoking.

Choosing your New Year’s resolution is the easy part, but sticking to it is the challenge.

Tony Horton, a fitness and lifestyle expert and creator of P90X, said oftentimes people set unrealistic expectations, which discourage them from staying committed.

“You can’t conquer the world in the first 15 days,” he said. “How about we just lose, you know, five pounds in the first couple of weeks? If you do that. And if you’re consistent with it, the more you do, the better you get.”

Horton said there’s also a lack of accountability.

“Who are you and what are you relying on to get through this thing? Your husband, your friend, your neighbor, your coworker, I mean, it’s nice to have company when you’re trying to make some changes,” he explained.

Horton recommends people write a plan of attack to help them stay committed to their goals.

“I always say, write it down, put it on your refrigerator, your front door, your bathroom mirror, because if you write it down, you’ll do it. If you’re winging it, you won’t,” he said.

Lastly, Horton said the resolution might not be compelling enough.

“Maybe it’s even too daunting to sustain long term. So it’s, it’s really important to kind of pick something that you think you can stick with,” he said.