In recent years, one of the most popular diet interventions has been fasting, in a variety of different forms. These have included intermittent fasting diets in which you’re supposed to fast for a few days per week, such as the 5:2 diet, or a few days per month. They’ve also included various forms of time restricted eating, such as the 16:8 diet, where you’re supposed to get all your calories within an eight hour window each day, and the more extreme warrior diet, in which you’re supposed to get all your calories in a four hour window. But there is still little clarity on how effective these modifications are in terms of weight loss. And up to this point, pretty much all the evidence in support of fasting comes from animal studies, which are notoriously unreliable.