5 things you should NEVER do when starting a new diet

When you're ready to kick some weight-loss butt and get in shape, you might look to an elimination diet, juice cleanses (please don't), or taking your diet to a Gwyneth Paltrow-level of clean. And 24 hours after starting whatever adventure you chose, you probably realize that was a big mistake.

"Change is hard, which is why it's best to start small and gradually incorporate more changes as you adjust to the previous ones," says Tory Tedrow, R.D., head of nutrition for SugarChecked.

Even when you find a weight loss plan that you can actually see yourself sticking with, it's easy to get off track—especially in the beginning. That's because your new habits haven't quite solidified yet, making it super easy to slide back into your old groove, says Tedrow.

Once your new plan is underway, protect the changes you're making by steering clear of these uber-common dieting mistakes that tend to strike near the starting line.

If you've thought about kissing dairy or gluten goodbye in the name of losing weight, that could be a big mistake. Ditching certain foods or food groups when you aren't legit allergic to them can seriously mess with your weight-loss goals. "Restriction can increase desire and for the restricted food and make your brain think it tastes even better once you actually eat it," says Adina Pearson, R.D., dietitian at the Walla Walla Clinic in Washington. Even worse, it creates scarcity and makes it more likely that you'll binge on the restricted food when you get the chance.

If you've ever eaten a frozen diet meal knowing that you'd be starving in T-minus 30 minutes, you know that portion-controlled meals don't always hit the spot. "Trying to control how much you eat via someone else's rules won't ever be as satisfying and sustainable as learning to respond to your own and fullness signals," says Pearson. If you're still full after eating a portioned out meal, it's unlikely you'll be able to stick your new diet over the long haul.

Those feelings of deprivation are enough to throw even the most determined gal off the healthy-eating bandwagon. "Eat to satisfaction rather than a preconceived idea of how much to eat," she suggests. "Be flexible and responsive to your needs."

You can totally follow a specific diet and exercise plan without going balls to the wall from day one, says Edwina Clark, R.D., head of nutrition and wellness at Yummly. Instead, incorporate it into your life in phases.

While we appreciate your enthusiasm, long-term weight loss success comes from making incremental changes to your lifestyle that you can live with year after year, says Clark. For lasting results (and to avoid backsliding), make changes to your diet and exercise habits at a pace you're comfortable with. For example, start by progressively adding more exercise into your routine and after that begins to feel normal, start making nutritional changes one at a time. It might take a few months.

Starting a new diet and exercise plan often involves more time and effort, and you might find yourself reducing the number of hours you sleep to fit everything in. But don't. "Our hunger and satiety hormones are brought into balance as we sleep and our muscles are repaired," says Caroline Apovian, M.D., director of the Nutrition and Weight Management Center at the Boston Medical Center.

Plus, your impulse control is at an all-time low after a night of ho-hum sleep, making it harder to resist temptations. One study even found that when people didn't get enough sleep, they ate an average of 385 more calories than usual the next day.

Running may burn more calories than yoga, but if you hate running, you're more likely to put off your workout. So, in the end, you might not burn any extra calories at all. "When it comes to workout plans, always choose a plan that includes exercise you enjoy," says Tedrow. You'll burn more calories from consistently doing yoga three or four times a week, than forcing yourself to run once or twice a week, he says.