As American waistlines continue to expand, so does the number of diet plans promising to shrink them. But many crash diets, juice cleanses, or canned smoothies often fail to deliver long-lasting results. Temporary changes in diet rarely solve the problems caused by years of unhealthy eating. Instead, guidelines that encourage long-term change in diet can make a significant difference in energy, weight, and overall health. To help decode all the health jargon, here are some of the most popular diet guidelines.

The Paleo Diet

A relative newcomer to the health and nutrition scene, paleo (short for Paleolithic) has rapidly gained popularity among fitness experts. Based on what proponents dubiously claim was the human diet during the Paleolithic era, the plan prohibits processed food, alcohol, dairy, legumes, and even salt. The focus is instead on natural, high-fat, high-protein foods such as grass-fed meat, fish, and vegetables. So while white bread might be taboo, bacon can now claim to be a health food.

For those hesitant to give up the occasional slice of cake or glass of wine, the paleo diet also includes the 85:15 rule, meaning that the diet must only be followed 85 percent of the time. This equates to roughly three non-paleo meals each week.

The paleo diet is best suited for weight loss, muscle building, or those prone to iron deficiency. Those suscepitble to high cholesterol levels are better off trying another food plan. More information about the paleo diet can be found here.

Gluten Free

Though generally prescribed for medical reasons, some believe a gluten-free diet can also prove beneficial to those without gluten allergies or Celiac disease. Proponents of the gluten-free lifestyle argue that gluten — a protein found in wheat, barley, and rye — can have myriad negative effects on those without a diagnosed gluten sensitivity, including weight gain, exhaustion, and even depression.

Starting a gluten-free diet can be intimidating, but there is a wide range of products available to keep restrictions as limited as possible. Gluten-free cereals, pastas, and baking mixes can often be found in the average grocery store, making it easy to make home-cooked gluten-free meals.

A gluten-free diet can be extremely helpful to those with severe food allergies, but it is generally not recommended for those simply looking for a healthier lifestyle. More information on gluten intolerance and a gluten-free lifestyle can be found here.

Vegetarian

As the FDA debates eliminating lean meat from its dietary guidelines, vegetarianism is shedding its hippie image. Though many people choose to eat vegetarian for ethical reasons, the diet also offers a number of health benefits, including higher energy, weight loss, and a stronger immune system.

This diet comes in several shades, ranging from standard vegetarianism to a stringent vegan diet. The differences are simply in the variety of animal products consumed.

Vegetarians choose not to eat animal flesh of any description, though they usually consume dairy and honey. Vegans eliminate all animal products and animal-derived products from their diet. This includes dairy, eggs, and honey. (Self-described “pescatarians” are not, despite popular myth, vegetarians, as they only eliminate meat and poultry from their diets, while continuing to eat fish, dairy, and honey.)

Due to their non-consumption of meat, vegetarians must be careful to ensure they have enough protein and iron in their diets.

All variants of vegetarianism have proven health benefits, including weight loss, reduced cholesterol, and reduced risk for heart disease. More information can be found here.

Photo by U.S. Department of Agriculture via Flickr