If you’re like many Americans, you made a resolution to lose weight and get in shape in 2014. And, if you’re like many Americans, you’ll step on the scale a few days into your new diet and throw your hands up in discouragement at the lack of "The Biggest Loser"-worthy numbers.

But "Biggest Loser" trainer Bob Harper says that reaction is a big mistake.

If you lose 1 to 2 pounds a week, you should be thrilled, he said, even though that would spell elimination on the NBC reality weight loss show, which returns Tuesday.

"People can never try to compete with the numbers they see on ‘The Biggest Loser,’" Harper said. "It’s not a real situation. It’s reality TV on steroids. Everything is so enhanced. You use the show as a motivational tool, but not as a way to compete from home."

Here are eight other mistakes you don’t want to make as you embark on a more healthful lifestyle in 2014. (Keep us apprised of your process by using the hashtag #LATFit on Twitter and Instagram.)

1. You wait for the motivation fairy to knock at your front door: "You have to realize that a healthy lifestyle takes commitment, and it takes drive," Harper said. "And never for a minute think it’s going to be easy because it’s not. … It’s going to be boring and monotonous at times."

2. You weigh yourself only every week or two: "If you’re trying to lose weight, you need to get on a scale every day or every couple of days," Harper said. This flies in the face of the notion that you need to give your new health regimen some time to work. But Harper says regular dates with a scale allow you to see trends and patterns between your diet and your food journal. Speaking of which …

3. You are keeping a food journal, right? This is probably the single most despised piece of advice in the diet-and-fitness realm. Yet it’s one of the most crucial, Harper said. Does the scale jump the morning after you’ve eaten high-sodium Chinese food? Does your weight nudge down a quarter-pound after three days of healthful eating and moderate exercise? That’s invaluable data.

4. You let the scale make you crazy: "Don’t define yourself by the number on the scale," Harper said. This may sound like it contradicts No. 2, but Harper said there will be many days when you step on the scale and it doesn’t budge. And that’s fine. Because progress can be defined in many ways. Maybe you’re feeling stronger during your workouts. "Maybe those jeans aren’t quite as tight."

5. You make grand goals that you cannot keep: "People say, ‘Oh, I’m going to start exercising all the time in 2014,’ and I say, ‘No, no, no.’ Let’s start with something doable. How about: ‘I’m going to work out three times a week no matter what.’ And then stick to that," Harper said. Same goes for your approach to your eating.

6. You think you can outrun the junk food: Folks who are watching this season of "The Biggest Loser" saw this mistake play out when Hap, who by all accounts was a monster in the gym, fell short on the scale week after week. "Hap really thought that, ‘Hey, I’m going to be able to eat what I want because I work out so hard,’" Harper said. But that thinking got Hap eliminated. "Diet is the most important element when it comes to weight loss," Harper said. "It’s No. 1 and No. 2."

7. You don’t change your priorities: It all comes down to this, Harper said: "Are you willing to change your priorities?" This goes hand-in-hand with No. 5, and it’s why he suggests finding achievable goals to build on throughout the year. "You need to look at your big picture and decide that you really want to change your lifestyle. And then you need to really take it seriously."

8. You get easily discouraged: "You have to be able to trust the process even when you don’t see it changing on the scale," Harper said. Setbacks are inevitable. "This is a lifestyle change. You need to recognize that. There are going to be ups and downs. It’s how you handle the downs that matter."