It’s time for 2019 New Year’s resolutions, and many resolutions revolve around improving health. Choosing the resolution is easy…now how will you achieve it? A quick Google search should do it. But now dietary advice pops up from every corner of the Internet citing seemingly strong support for their way being the BEST way to achieve your goals. You will find endless dietary trends: everything from paleo to gluten free, low FODMAP to Weight Watchers with everything in between. So how do you know which one is right for you?

Let’s break down the scientific research behind five of these trendy diets:

1. The Paleo Diet

What is it?

The Paleo Diet loosely mimics nutritional patterns from the paleolithic era approximately 10,000 to 2.6 million years ago. It emphasizes consumption of fruits, vegetables, nuts, and animal proteins, with minimal inclusion of sugar, grains, legumes, dairy, and processed foods.

What does the research say?

Long-term paleo diet may be associated with:

Bottom Line: Positive outcomes are associated with the paleo diet, though researchers question whether these are because of the diet itself (no grains, dairy, sugar, etc.) or the benefits of increasing nutrient dense fruits and vegetables.

2. A Plant-Based Diet

What is it?

A plant-based diet promotes high intake of foods derived from plants, and limits or completely excludes animal products (meat, poultry, fish, dairy). It is most often associated with a vegan or vegetarian diet.

What does the research say?

A healthy plant-based diet appears to be associated with:

  • A lower risk of mortality.
  • A lower body mass index (BMI)in those who follow a vegetarian diet, when compared with the BMI of a nonvegetarian.
  • This same articlepointed out potential nutrient concerns for those following a strict plant-based diet: vitamin B12, zinc, and protein. Complete exclusion of all animal products puts one at higher risk for inadequate intake of these nutrients.
  • One articlefound that production of food for a nonvegetarian diet required 2.9 times more water, 2.5 times more energy, 13 times more fertilizer, and 1.4 times more pesticides than a solely plant-based diet.

Bottom Line: A plant-based diet supports environmental sustainability, and may lower risk of mortality and a high BMI. However, if you choose to be strictly plant-based, it’s important to be aware of nutrients that may be lacking and modify your diet accordingly.

3. The Ketogenic Diet

What is it?

The ketogenic diet focuses on very low-carbohydrate intake and very high-fat intake, with the goal of using fat as the body’s primary energy source instead of glucose. A medical ketogenic diet can be used to treat seizures primarily in children with epilepsy, and occasionally in adults with epilepsy as well.

What does the research say?

  • One study reported that in overweight and obese men, 4 weeks of a strict ketogenic diet resulted in reduced body weight but did not alter their energy expenditure or increase fat loss.
  • Another study compared a strict ketogenic diet with a nonketogenic low-carbohydrate diet and found that both diets were equally effective in reducing body weight and improving insulin resistance. However, they also found that the ketogenic diet resulted in elevated LDL and cardiac complications, in addition to adverse emotional and mental effects.

Bottom Line: The ketogenic diet may promote weight loss and improve insulin resistance but appeared to be no more effective than a less restrictive low-carbohydrate diet and may be associated with more adverse metabolic and mental side effects.

4. The Gluten Free Diet

What is it?

A gluten free diet is one that excludes all food items containing the protein gluten. This means exclusion of anything containing wheat, barley, rye, and any derivative of these grains. A gluten free diet is recommended for individuals with celiac disease.

What does the research say?

  • Non-celiac gluten sensitivityis recognized in some individuals, and they may benefit from a gluten free diet to avoid adverse symptomatic responses to gluten.
  • A study measured levels of plasma proteins involved in inflammation and observed correlation with gluten intake in young adults not affected by celiac disease. They found that increased gluten intake was associated with increased concentrations of plasma a2-macroglobulin, which is a marker of inflammation.

Bottom Line: Anyone with celiac disease is recommended to follow a gluten free diet. Some individuals may benefit from a gluten free diet due to non-celiac gluten sensitivity, but diagnosis for this condition is not yet readily available.

5. The Mediterranean Diet

What is it?

The Mediterranean diet focuses on whole foods like fruits, vegetables, nuts, whole grains, healthy fats and oils, poultry, seafood; allows moderate inclusion of alcohol (red wine) and dairy products; and limits inclusion of added sugar and red meat (Whalen 2016).

What does the research say?

The Mediterranean diet may be associated with:

Bottom Line: Research shows some benefits may be associated with the Mediterranean diet, related to inflammation, lower mortality risks, and reduced blood pressure.

The path to a healthier 2019 will look different for every person, and learning the research behind different diets will help you find YOUR best path. Unsure how to interpret all this research on your own? Consider talking with your healthcare provider or a Registered Dietitian! They can help you decide which lifestyle changes and diet trends will best fit you and your goals, and set you on the right path for the New Year.