CLEVELAND -- High protein, low carb -- it's all the rage. But while those diets can really work, that doesn't mean they are healthy.

LOW-CARB DIETS Menu Maker Lowdown On Low-Carb Diets Diary Of A Fat Man Discuss Atkins On Low-Carb Diet? How Low-Carbing Works How Atkins Works

"That rapid weight loss is due to the water loss. The first seven pounds that you lose within 24 to 48 hours is all water," said Lisa Cimperman, a registered dietician at University Hospitals in Cleveland.

And what you're left with is the same diet for the rest of your life, unless you want to gain the weight back.

Cimperman said it's unrealistic to think the Atkins diet is a way of life, especially if you have underlying health conditions.

Cimperman said research is being conducted right now about how these diets affect our health.

"Some studies have shown a lowering of cholesterol with these high-protein diets, but I think we're still in the dark as far as what the long-term consequences are," said Cimperman.

One thing that has been found is that high-protein diets can cause dehydration.

Dehydration puts an extra burden on the kidneys, which are also strained from separating the waste products from the protein in a high-protein diet.

In severe cases, dehydration could cause a person to go into acute kidney failure.

Experts say to include lean protein in every meal. If you eat carbs, choose those that are high in fiber, such as whole grains and wheat products.

It is also important to eat vegetables and fruit, drink plenty of water, and exercise as much as you can.