If you’ve got low-carb, low-fat or other restrictive diets on your mind, it’s wise to remember they’re typically less effective than an overall healthy approach to food, such as the Mediterranean diet. (For Spectrum Health Beat)

Whether you’re looking to lose weight or improve your overall health, think twice before jumping onto the “free diet” bandwagon.

What you don’t know could hurt you, according to Jessica Corwin, a registered dietitian at Spectrum Health Healthier Communities.

Here’s her perspective on why diet fads are popular and what you need to know.

Fat-free or low-fat diets

Why it sounds appealing: In the early ’70s, scientists found a link between fat and heart disease. As a result, no-fat and low-fat diets were promoted as the key to good health and weight loss.

“Manufacturers jumped on board and we moved into the Snackwell era of fat-free everything,” Corwin said.

It hasn’t helped.

People have been eating less fat over the past 30 years, yet obesity rates have continued to rise.

What you should know: Not all fats are created equal and you actually need some fats in your diet to stay healthy.

“Certain fats are good in moderation,” Corwin said. “For example, the Mediterranean diet is one of the healthier ways of living even though it contains up to 35 percent fat with oils from avocados, olives and other foods.”

Mono and polyunsaturated fats are beneficial because they are a major source of energy, they tame down inflammation and they even help create healthy skin and hair. Keep in mind that the American Heart Association recommends limiting saturated fats in your diet. Stay tuned: There’s growing research to indicate that certain types of saturated fat, such as those from dairy or tropical oils, may be less harmful than others (including meat).

You also need fat in your diet to absorb vitamins A, K, D and E. Corwin discourages her clients from using fat-free salad dressings. Without the fat, your body can’t absorb nutrients from the vegetables in your salad.

Plus, fat-free food is less satisfying.

“You’ll feel more satisfied eating one ‘real’ cookie or a very small piece of cake than devouring a whole sleeve of fat-free snacks,” Corwin noted.

Gluten-free diets

Why it sounds appealing: Some people have celiac disease or gluten intolerance and truly benefit from going gluten-free. But that doesn’t mean eliminating gluten is right for everyone.

“There is a huge ‘health halo’ around gluten-free foods today,” Corwin said. “People are going gluten free because they think it will help them lose weight. That can easily backfire.”

What you should know: Processed, gluten-free foods are loaded with fat and sugar to add flavor. You could end up getting more calories and less nutrition.

On the positive side, the gluten-free movement is encouraging people to try whole grains they’ve never tried before.

“I encourage people who are gluten free to expand their cooking repertoire,” Corwin said. “It’s a good opportunity to try whole grains and protein-packed seeds. Look for recipes with quinoa, amaranth, teff or millet. The key is to think outside of the (processed) box.”

Carb-free or low-carb diets

Why it sounds appealing: It may work for a while.

Many people quickly dropped 20 pounds or more when they eliminated carbohydrates with the Atkins diet. The problem was the weight returned when they started eating normally again.

Today, the Paleo diet is gaining traction. It has several drawbacks, however, and some people may misinterpret its guidelines. It can also be short on micronutrients. (Why eat a diet based on an era when the average lifespan was in the 20s?)

What you should know: Carbs are important for a well-balanced diet. In moderation, eating the right carbs can add fiber, improve your mood and maybe even help you lose weight.

“It’s not realistic for most people to keep certain foods ‘off limits’ for the rest of their lives,” Corwin said. “You might be able to quit something for a few weeks or months, but chances are you’ll go back and eat those foods with a vengeance later.”

Sugar-free diets

Why it sounds appealing: Food manufacturers have promoted sugar-free foods and diet sodas as the way to stay slim and healthy.

What you should know: Read the labels carefully. If you are picking sugar-free goods, be aware of the artificial sweeteners you are ingesting and know how much is too much. Sometimes sugar alternatives are worse than sugar itself.

You may see the words “no added sugars” or “no high fructose corn syrup,” but the food contains aspartame, saccharin or the newest zero-calorie sweetener, Stevia, which sounds healthy because it is extracted from a plant. (A word of caution: Not much research has been done on its health impact.)

The best approach is a natural one

Corwin isn’t surprised that people get confused about nutrition. New studies come out every day and the recommendations change often.

Her advice: Unless you have health concerns such as diabetes or celiac disease, just eat a balanced, natural diet.

“The best foods are straight from nature and don’t even have labels,” she said. “If a manufacturer is trying too hard to sell you on the idea that a food is healthy, take out a magnifying glass for a good look at what’s inside.”