Different methods of intermittent fasting have gained popularity recently, and a new study finds one of the most extreme versions—alternate day fasting—showed no signs of harming participants even after six months. Researchers said participants found fasting easier to stick to than restricting calories. They reported alternate day fasting seems to work as well as restricting calories, and they reported a number of health benefits as well as weight loss.
Researchers said participants did not find hunger or lightheadedness a big issue after the first two weeks. Nutritionists who were not involved in the study say alternate day fasting can be difficult. Previous studies conducted over a shorter term have found people struggled with zero-calorie alternate day fasting.
Findings are reported in Cell Metabolism
The new study that was reported in Cell Metabolism required people on the alternate day fasting diet to give up solid or liquid foods and drinks that contained calories. On the other days they could eat whatever they wanted. This form of intermittent fasting is also known as the 36/12 fast.
A different form of alternate day fasting, which was not used in the new study, allows eating 500 calories one day and then eating whatever you want on the following day.
Other versions of intermittent fasting that are growing in popularity are the 16/8 and the 5/2 plans. The 16/8 fast is called time-restricted feeding, where you pick an eating window of eight hours each day and fast for the remaining 16 hours. Experts recommend a window that ends early because your body is more efficient at breaking down sugar earlier in the day. An example would be planning to eat between 10 a.m. and 6 p.m.
The 5/2 plan requires fasting two days during the week and then eating normally the other days. The fasting days cannot be consecutive. You might pick Monday and Thursday to fast, but you would not fast on Tuesday and Wednesday.
Benefit from eating between 10 or 12 hours
Some experts on intermittent fasting say the key to real success is trying to eat as healthy as you can, and to make sure you eat healthy foods on the days when you can eat whatever you want.
Health benefits that researchers reported in the new study on alternate-day fasting found improved cardiovascular markers, reduced blood pressure, and had lower heart rates after four weeks. Participants who followed the alternate-day plan for six months ate about 37 percent fewer calories and reduced fat distribution in their trunk and abdomen by about 14 percent on average. Lower levels of LDL “bad” cholesterol and triglycerides were seen in people who followed alternate day fasting compared to those who ate normally.