Alternate day fasting research
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Alternate Day Fasting for Weight Loss and Body Composition
Research consistently shows that alternate day fasting (ADF)—where individuals alternate between days of very low calorie intake and days of eating freely—leads to significant weight loss in both obese and non-obese adults. Studies report reductions in body weight ranging from about 2.5% to over 6% within 3 to 12 weeks of ADF, with most of the weight lost coming from fat mass rather than lean mass 1235+2 MORE. ADF is also effective in reducing fat mass and improving the fat-to-lean mass ratio, with similar results seen in people with non-alcoholic fatty liver disease (NAFLD) . When compared directly to daily calorie restriction, ADF produces similar weight loss and body composition changes 410.
Cardiometabolic Health and Disease Risk Markers
ADF has been shown to improve several markers of cardiovascular and metabolic health. Studies report significant reductions in total cholesterol, low-density lipoprotein (LDL), triglycerides, and blood pressure in adults following ADF 1238+1 MORE. Some research also notes increases in high-density lipoprotein (HDL) cholesterol and improvements in inflammatory markers such as C-reactive protein (CRP) and sICAM-1 18. However, not all studies find consistent changes in fasting glucose, insulin, or insulin resistance, and some markers like HDL, homocysteine, and resistin may remain unchanged 1249.
Appetite, Hunger, and Adherence
ADF can increase hunger, especially on fasting days, and this sensation may persist over time, potentially making long-term adherence challenging for some individuals . However, other studies suggest that after several weeks of ADF, there is no compensatory increase in hunger, and feelings of fullness may actually increase, possibly aiding dietary compliance . Adherence rates to ADF can be lower than daily calorie restriction, with some participants finding it difficult to stick to the regimen over longer periods .
Effects on Aging and Chronic Disease Prevention
Short-term ADF in healthy, non-obese adults has been shown to improve physiological and molecular markers associated with aging, such as reducing pro-aging amino acids and inflammatory markers, and increasing beneficial metabolites like β-hydroxybutyrate . Animal studies suggest ADF may reduce the risk of diabetes, cardiovascular disease, and cancer, but human evidence for cancer prevention is still lacking . Overall, ADF appears to modulate several risk factors for chronic disease, with effects similar to those seen with continuous calorie restriction .
Comparison with Other Dietary Approaches
When compared to daily calorie restriction or time-restricted feeding, ADF generally produces similar improvements in weight loss, body composition, and metabolic health markers 34910. There is no strong evidence that ADF is superior to these other dietary strategies, but it remains a viable alternative for those who prefer intermittent fasting patterns.
Safety and Feasibility
ADF is generally safe for healthy adults, with no serious adverse effects reported in studies lasting up to six months . However, persistent hunger and lower adherence rates may limit its practicality for some people 45. Modifying the fasting day to include a small meal may help improve long-term compliance .
Conclusion
Alternate day fasting is an effective and safe dietary strategy for weight loss and improving several cardiometabolic risk factors in both obese and non-obese adults. While it offers similar benefits to daily calorie restriction, individual preferences and the ability to adhere to the regimen should be considered when choosing a dietary approach. More research is needed to confirm its long-term effects on chronic disease prevention and to identify strategies to improve adherence.
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