The 5 2 in this diet refers to the five days where you eat whatever you like, and then you fast for two days. During the two days of fasting, a woman is allowed to consume 500 calories while a man is allowed to consume 600 calories. Then you repeat the cycle as many times as you want. This diet fad has been around since 2012 and originated in the UK. There aren’t any food restrictions. You can eat whatever you want. Obviously, the more sensibly you eat, the better the results. People on this diet can expect to lose about a pound a week. There is a report of a man who lost 50 pounds total. Obviously, this is another calorie restricting diet.
One of the unpleasant effects for the participants is feeling hungry on the two fasting days. Not surprisingly, participants complain of headache, low energy, and dizziness on the fasting days as well. To minimize these side effects, proponents of the diet recommend not fasting on two consecutive days. In addition, they recommend drinking plenty of fluids including water and tea. Eating wisely during the fasting days is emphasized as well. For example, you can eat salads without salad dressing or with minimal salad dressing during your fasting days which will make you feel full, but will have minimal calories. Light exercising is encouraged, but strenuous exercise is discouraged especially on the days of fasting. Exercise is generally not recommended on a calorie restricting diet due to feeling light headed and dizzy.
Everyone should consult their physician before starting a diet, but this is especially true for people with chronic illnesses like diabetes.
As of this date, there are few studies that have addressed this diet, so long term safety is unknown. The benefit of this diet is that participants may be able to follow this diet for a long period of time as the fasting is confined to only two days a week. The benefits that have been found, after following this diet, include a reduction in insulin and improvement in insulin sensitivity. Other positive benefits include decreased triglycerides (a good thing), increased low density lipoproteins (another good thing), decreased C reactive protein (an indicator of inflammation in the body), and decreased leptin. This was in addition to losing weight as a result of fat loss while sparing muscle mass.
For the most part, dieters using this plan are happy with the results, and feel that the diet is not too stringent. And, there are the positive side effects as mentioned above. I should mention that the proponents of the diet recommend weighing once a week as opposed to weighing every day as weight can fluctuate on a daily basis. Weighing once a week will provide a more accurate assessment of your progress.
The best diet is the diet that the dieter can follow long term and this appears to be such a diet. I still recommend eating wisely and exercising instead of dieting, but some people prefer to diet. If you decide to follow this diet, please leave a comment, and let me know how the diet worked for you.
Wishing you continued success in your weight loss and maintenance. Pablo.