High fat, low carbs. Low fat, high protein. There are lot of fad diets out there, and they each promise a different way to lose weight — fast.

But do these diets actually work? And even if they do, are they safe?

Hartford HealthCare bariatric specialist Joseph St. Pierre, DO, has advice.

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Fad diets don’t work unless you stay on them forever – and in most cases, you shouldn’t.

From the caveman diet to Keto, raw food to the Zone, any number of diets can result in short-term weight loss. Unfortunately, the emphasis is on short-term.

“With fad diets, the big issue is, what do you do when the diet is over?” says Dr. St. Pierre. “Typically, people just go back to eating or doing what they did before. When you do that, your weight rebounds.”

So when you’re considering the latest dieting trend, you have to ask yourself: Are you really going to keep it up for the rest of your life?

If the answer is no, studies show you’ll probably wind up right back where you started.

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Often, fad diets lack important nutrients.

It’s not just that fad diets tend to fizzle. Sometimes, they’re also bad for you.

For instance, if you’re eying Beyoncé’s lemon juice and cayenne cleanse (please don’t), it’s pretty clear you won’t be getting a balanced meal.

But other popular diets have nutritional gaps in them too. For example, experts say the Atkins diet is far too low in calcium, and the Zone, macrobiotic and raw food diets are light on other key nutrients.

In particular, avoid any diet that promises rapid weight loss.

“Rapid weight loss takes a toll on the body,” says Dr. St. Pierre. “There are health risks with any diet that causes you to lose too much weight in a short period of time.”

Rapid weight loss can lead to:

  • Gallstones
  • Dehydration
  • Malnutrition
  • Electrolyte imbalances
  • Fatigue
  • Hair loss
  • Muscle loss

Instead of the latest diet trend, try talking to your doctor.

There are rarely quick fixes in life, and “miracle diets” are no exception. A better approach is to get to the root of the problem.

“Unwanted weight is caused by an energy mismatch between the energy you receive from food and the energy you burn,” says Dr. St. Pierre. “You need to address the underlying cause for the energy mismatch.”

Whether that’s an issue with the food you’re eating, the physical activity you’re getting or an underlying health condition — or some combination of these factors — your doctor can help. They can work with you on a personalized plan that addresses your weight loss goals and your long-term health.

Because trends come and go, but your body is with you for life.