If you're looking to lose weight longterm, the 5:2 diet may not be the best plan for you.
The plan requires dieters to eat normally for five days of the week, then says women should eat 500 calories per day and men should eat 600 calories per day for two other days.
But a new study has found people on a standard diets who simply cut down on their daily calories lose almost the same amount of weight as people on the more restrictive 5:2 diet.
In a study by Austin Health and the University of Melbourne, 24 obese men either cut their regular food intake by 600 calories or followed the 5:2 diet under the instruction of a group of dieticians.
After six months, both groups reduced their body fat and waist size, but the men in the 5:2 group reported lower levels of food satisfaction.
Those in the 5:2 group reduced the percentage of their body fat by 1.3% compared to men in the standard calorie-reduced diet group, who dropped by an average of 2.3%.
However, men in the 5:2 group had a slightly better result when it came to measuring waist size, losing 8cm compared to 6.4cm.
According to The Guardian, one of the researchers, Margie Conley, said: "Compliance rates were similar for the two groups, but the 5:2 diet group reported being hungrier, especially early on in the study.
“Interestingly, weight loss slowed at the three-month mark for both groups, which was when the dietitian follow-up tapered out, showing support may be the key element in continuing success."
Previously speaking to The Huffington Post UK Dietitian Priya Tew raised concerns about the restrictive nature of the 5:2 diet.
"Essentially this diet limits the calorie intake on two days so reducing the calories eaten in the week," she said.
"The issues can come on the fasting days, when the fasting can impair concentration and mood plus making it difficult and not sensible to exercise, so this diet could be impractical."