The 6 biggest mistakes to avoid when going Paleo

Between their unstylish loincloths, their less-than-ideal grooming situations, and the whole having to discover fire thing, cavemen didn't have a lot going for them—except for their diet, which is making a huge comeback thousands of years later.

Well, as with any diet, there are a number of pitfalls that you need to watch out for if you're taking up a caveman lifestyle to lose weight. Read ahead for the biggest mistakes to avoid when going Paleo.

Brooke Alpert, R.D., founder of B Nutritious, says that foods with certain labels like Paleo, gluten-free, or organic make you think they're weight-loss friendly, but you could be sabotaging yourself by noshing on a packaged Paleo treat. "A Paleo cookie is still a cookie," says Alpert. Plus, she says, many Paleo-friendly products are high in carbs from dried fruit, which can make you retain water. That's not so great for your weight-loss goals. Instead of picking up a pack of grain-free, soy-free, dairy-free snacks, go for fresh cut veggies and guac, a handful of nuts, or a small dish of berries.

It's important to remember that the Paleo diet isn't just about eating truckloads of meat, says Alpert. "There's a misunderstanding that the Paleo diet is just meat on top of meat, and some bacon on top," she says. And while protein is super filling and can help you build metabolism-revving muscle, no more than one-third of your plate should come from protein sources per meal, says Mandy Enright, R.D.N., creator of the couples nutrition blog Nutrition Nuptials. Ideal protein sources include lean cuts of beef, fish, and poultry.

With one-third of the real estate on your plate occupied by protein, fill half of it with veggies and or fruit, says Enright. That's because low-calorie veggies fill you up with fiber, which helps your digestion stay on track and keep you from snacking an hour after dinner. After giving priority placement to your greens, dedicate the rest of your plate to healthy fats, like avocado, nuts, and seeds. Keeping your meal balanced with filling protein, satiating fiber, and satisfying healthy fats can keep your diet on track for weight loss, she says.

When you're saying buh-bye to dairy, legumes, and grains, you might miss out on some important nutrients, especially calcium, vitamin D, and fiber, says Enright.

"Weight loss is not smart or effective if you're creating a nutrient deficiency in the process," she says. If you're going full-on Paleo, Enright recommends working with a registered dietitian to ensure you're getting all the nutrients you need. But in the meantime, try eating more fresh fruits and vegetables at each meal to get enough fiber in your diet. Dark, leafy vegetables like collard greens, kale, and spinach, as well as cruciferous vegetables like cauliflower, broccoli, and Brussels sprouts are good non-dairy sources of calcium. Then, you can get your vitamin D fix from mushrooms and egg yolks, says Enright.

Besides making sure you're getting the right ratio of nutrients on your plate (see items two and three), it's very important to watch your portions on the Paleo plan, says Kristin Reisinger, R.D., C.S.S.D., founder of IronPlate Studios. Even if you're slashing food groups and loading up on veggies, you can slow your progress or even gain weight if you don't watch how much you're eating, says Reisinger.

When it comes to fibrous vegetables, the sky is the limit, Reisinger says. Leafy greens, broccoli, and cauliflower are all low in calories, high in fiber and water, and help with weight loss (in case you didn't catch that the last few times we mentioned it). For the average woman hoping to slim down, she says a portion of lean protein should be between four and six ounces (about the size of a deck of cards). Then, stick with a Tablespoon of healthy oils like olive oil, and a three- to four-ounce portion of starchy carbs. (Yes, we said carbs. More on that in a minute.)

Just because a diet is popular it doesn't mean it's the right fit for you, says Enright. Any diet that requires you to remove entire foods groups, if you're not intolerant or allergic, is a red flag, she says. "I tell my clients who choose to follow these diets to proceed with caution."

That means making your own food rules, even if you're basing a majority of your meals on the diet. That might mean following the Paleo principles of reducing the amount of sugar, processed foods, and alcohol you consume, while eating more lean protein and loads of veggies. But whole grains, legumes, beans, and dairy should be fair game, she says. That will help you stay on track with healthy eating without feeling deprived, she says. Ultimately, that's a healthy eating plan that leads to long-lasting results.