It's the year when diets are all the rage. With "get healthy" topping the list of most popular New Year's Resolutions, many are looking to change their eating habits to make 2017 their healthiest year yet.

Unsurprisingly, the fat and sugar-laden American diet is really bad for our bodies and our brains. But where to start? There are a million "top-rated" diets out there, all promising the same results.

Of course your doctor is a good place to start. Or check out this U.S. News list, which rates 38 of the most popular diets. And if you're looking to get both your body and your brain healthy, an observational study published in Neurology might point you in the right direction.

Researchers from the University of Edinburgh measured the brain volume of 400 participants at age 73, then again at 76. Participants were asked to rank how closely their diets followed the Mediterranean-style diet. The brains of those who stuck closely to this diet fared far better. Their brains lost less volume, meaning they didn't age as quickly. "Those with the strongest adherence averaged 10 milliliters greater total brain volume than those with the lowest," writes Nicholas Bakalar for New York Times Well.

The Mediterranean diet has long been heralded by doctors and scientists as one of the best. It's shown to reduce the risk for diabetes, heart disease, stroke and a number of other chronic diseases. U.S. News also named it as the second-best diet overall out of the 38 they analyzed. The diet emphasizes eating fruits, vegetables, oils, whole grains, legumes and fish.