Also known as alternate day fasting, "zigzag" caloric cycling calls for the dieter to eat the number of calories required to maintain weight one day, and then 25% of his or her energy needs on the fast day. Studies have shown that individuals who are compliant with this pattern can lose 4% to 8% of their body weight over 8 to 12 weeks.
People who need to lose weight often look for diets that deliver results with little inconvenience or sacrifice. In the last decade, some dieters have turned to alternate day fasting (ADF, also called zigzag caloric cycling), and this is an effective path to weight loss for certain individuals. It is based on studies in which animals alternated between free feeding and complete fasting every other day. In humans, zigzagging is modified so that the dieter eats the number of calories required to maintain weight one day, and then 25% of his or her energy needs on the fast day. Studies have shown that individuals who are compliant with this pattern can lose 4% to 8% of their body weight over 8 to 12 weeks. In addition, they tend to also experience reductions in low density lipoprotein (LDL) cholesterol, triglycerides, systolic blood pressure, insulin resistance, and increases in LDL particle size.
Researchers at the University of Chicago in Illinois wondered if ADF is tolerable for most people. They structured a study to look at whether changing the times dieters consumed calories on the fasting day would make a difference.
They randomized 74 participants with BMI between 30 and 39.9 kg/m2 to one of three arms:
They compared effects on body weight and heart disease risk. Participants ate their normal diets in the 2 week run-in period, and then followed a weight-loss ADF plan. On fast days, they typically consumed 500 calories.
Participants in all arms experienced similar reductions in body weight and lost approximately 4 kg during the 10 week study period. They also had similar reductions in fat mass and visceral fat; they lost 75% of weight as fat and 25% lean.
This study showed that regardless of when fasting day meals were consumed, participants lost weight. They also experienced improved cardiovascular parameters. Zigzag caloric cycling may be a good option for patients interested in losing weight and willing to restrict calories every other day.