The 5:2 diet is a type of intermittent fasting protocol.
(It) involves five days per week of habitual food intake without restriction, with two consecutive or nonconsecutive days of substantial calorie restriction
Scientific data on the effectiveness of the 5:2 diet is relatively limited, but it has worked for some people.
When you compare the 5:2 diet with continuous calorie-restricted diets, studies show no significant difference in weight loss and cardiometabolic risk reduction.
A key determinant of how much weight you can lose with the 5:2 diet depends on how long you can stick with it.
When you fast, you'll significantly restrict your calorie intake.
Planning in advance can help you stay within your calorie allowance on fasting days.