According to Google Trends, people have gradually become less interested in low-fat diets and more into low-sugar diets:
The chart was part of a response by Martijn R. Tannemaat and N.A. Aziz from Leiden University to a larger, controversial BMJ article by the journalist Nina Teicholz on the scientific merit of dietary guidelines. Tannemaat and Aziz note that Google searches for “low fat” have declined gradually since at least 2004, while those for “low sugar” have become increasingly common and will probably overtake “low fat” this year.
“This is cause for modest optimism with regard to future obesity rates,” the authors write, “as recent data indicate that a diet low in carbohydrates is probably more effective in reducing obesity and its associated cardiovascular risks than a low-fat diet.” But not too much optimism: “only a small minority of all new year's resolutions are actually kept.”
It’s also not a cause for optimism because there’s a ton of hidden sugar in random foods like chicken salad, as I wrote about a few months ago.