This simple intermittent fast (today referred as a 5:2 diet) was not the first of its kind to go mainstream, but it became an international sensation. Today there are dozens more variations, with books, apps, wearables and supplements to support them. And they’re very popular: The International Food Information Council, a nonprofit tied to the food industry, surveyed 3,000 American adults and found that 13 percent have experimented with intermittent fasting in 2024.