Alternate-Day Fasting as a Weight-Loss Ruse

Google “weight loss” and you get over 105 million items.  Most of these contain some form of advice, but the bottom line from a simplistic standpoint lies in the equation:  Calories In – Calories Out = Weight Change.  Lowering your daily calorie intake becomes a terrible bore after quite a short period, and calorie-restriction diets don’t have many successful followers.  This led University of Illinois researchers to study a formalized approach to a method that’s been around for a long time – fasting days interspersed among normal eating days.  They’ve reported their results in the American Journal of Clinical Nutrition. 

A 10-week trial was done in 16 clinically-obese subjects – 12 women and 4 men between 35 and 65 – all of whom weighed over 210 pounds.  Their body mass index (BMI) values lay between 30 and 40.  For the first 2 weeks, the participants ate and exercised normally.  From weeks 3 to 6, they ate normal meals one day and would partially fast the next.  On these ‘fasting’ days, they ate the equivalent of a 3-course lunch prepared by the university’s nutrition center, which provided 20%-25% of their individual energy needs.  From weeks 7 to 10 they were given expert dietary counseling on menu options, but they were allowed to choose what they ate.

It took about 2 weeks (i.e. weeks 3 & 4) for most participants to adjust to the diet, after which they didn’t feel hungry on the fasting day.  Over the full 10-week period weight loss ranged between 10 to 30 pounds; the average loss was 12.3 pounds.  This was greater than the researchers had expected - only 5 pounds.  Percentage body fat decreased by an average of 3%, and lipid levels were lowered by about 25%.  Average systolic blood pressure fell from 124 mm Hg to 116 mm Hg. 

Quite impressive results.  Of course, the tricky part for the subjects comes after the first 8 weeks of alternate-day fasting, but this will certainly be studied, in view of the success of this short pilot study.