• The first step to overcoming unhealthy eating habits is to identify the bad habits and understand why they exist.
• To successfully break bad eating habits, it's important to gradually incorporate small, manageable changes to your diet and lifestyle.
• If you fall back on a bad habit, be easy on yourself. One slip-up won't ruin your diet, psychologists say.

Whether you're trying to lose weight or just eat healthier, sticking to a new diet is tough. Because you're not just breaking one eating habit but you're building a new one at the same time.

"My clinical approach with my clients is to gradually change a few number of factors first. Because we have a finite amount of willpower, and the more things we remove...the harder it is" says J. Ryan Fuller, PhD, a clinical psychologist and executive director of New York Behavioral Health who specializes in weight loss.

Breaking habits - especially the kind that trigger your brain's reward centers, like when you gorge on ice cream - takes time and effort.

Here are the strategies that clinical psychologists who specialize in weight loss recommend if you want to change your diet habits in a safe, sustainable way.

How to break the habit of a poor diet

"I advise people not even to call it a diet. That brings up all kinds of negative emotions and expectations, such as deprivation, rules, food logs, etc," says Kimberly M. Daniels, PsyD, who specializes in overeating and weight issues.

Daniels explains that when it comes to breaking bad habits, it is helpful to think of current habits in terms of self-care.

"Binge eating ice cream every night would easily be defined as a bad habit, but people do that to soothe or comfort themselves. So it's actually self-care. Self-care that doesn't get you anywhere good, but still self-care."

Daniels recommends trying to uncover why you are performing this self-care habit by asking yourself some questions.

• If you're eating ice cream every night, why?
• What are you avoiding?
• What are you distracting yourself from?
• Why do you feel the need to comfort yourself in that way?

Once you understand your reasons more clearly, you can start to address the real cause of the behavior and break the bad habit. For example, "if you're eating ice cream every night because you're lonely, how can you boost your social connections?" says Daniels.

Strategies for adopting healthy eating habits

When developing better eating habits, mental setbacks are a natural part of the process. Try following these three pieces of advice when you first start tackling a new habit:

1. Manage your expectations: "I often find that people feel unworthy of something better," says Daniels. "Many people feel horrible about themselves." So, as you develop good habits, it's important that they're not only good by nature but that they make you feel good, too.

To achieve that, it's important to manage your expectations accordingly. For example, Daniels says that happiness is often an expectation for those who lose weight. When happiness doesn't necessarily occur, they give up.

What research says: A 2014 study that analyzed 1,979 patients over four years found that there wasn't a significant psychological benefit for those who lost weight versus those who either gained or remained at their starting weight. In fact, patients who were trying to lose weight reported feeling a more depressed mood.

That's why being realistic with yourself about what you hope to accomplish by adopting healthier eating habits is essential. If it is to lose weight, ask yourself why is this important to you, and what do you expect to gain from losing weight? "It's extremely important to make your expectations realistic," says Daniels.

2. Set realistic goals: Set realistic goals when it comes to implementing new eating habits. Overloading yourself with too many changes at once can become overwhelming.

"I always say slow and steady wins the race. Traditional diets don't work because they ask you to make 27 changes all at the same time. That's impossible", Daniels says. She suggests choosing one or two simple aspects of your diet that you'd like to work on at a time and don't make any other changes until you have those down.

3. Focus on adding foods, not cutting them: As you start to make those changes, focus on adding healthy foods into your diet rather than on cutting unhealthy foods out, such as sugar or carbs. Removing foods makes you feel deprived. Whereas adding foods gives you a sense of accomplishment.

How to stick to your new diet

When starting a diet, you might have a day or a week where you go off your diet or indulge in food you're trying to cut out. If this happens, Fuller says the best thing you can do is get right back on your diet the next day.

"It's not as though even a day slip or a week-long slip has to totally change their outcome. It simply slows it down or delays it by a week," says Fuller. "I help my clients practice self-compassion and acceptance even when they make a mistake. I help them recognize they can just start over in terms of being back on plan the next day."

In the end, it's all about sticking with your new habit long-term.

What research says: A 2005 review analyzed the data of 4,000 patients listed in the National Weight Control Registry and determined that those who kept weight off for two to five years after beginning their diet were able to maintain healthy lifestyle habits afterward.

Daniels explains that in the beginning, you will be very aware of what you're eating all the time. Thinking about whether or not you are hungry and if not, why you're choosing to eat is something that takes practice.

Daniels also says recognizing what might trigger a slip-up can help you avoid them in the future.

Insider's takeaway

You know you can stick to a new diet when that diet no longer feels new and becomes second nature. To achieve that, it's as the saying goes "practice makes perfect" and sticking to your new healthy eating pattern is no exception.

"That does get easier over time, especially if you realize you have patterns such as always eating when you're tired or bored. Once you realize this, you can plan for it and avoid it," says Daniels.

If you do slip-up, know you can get back on track the next day. Taking a gradual approach to changing your dietary habits will be more sustainable in the long-term than taking an "all or nothing" approach.

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