Generated Summary
The document discusses the potential of dietary interventions, specifically those that mimic fasting, to extend lifespan and improve health. It explores the concept of caloric restriction and its effects on aging in animal models and humans. The article focuses on the feasibility and practicality of implementing caloric restriction in humans, given the challenges of long-term adherence to strict dietary regimens. It then delves into the use of fasting-based approaches, such as time-restricted feeding and intermittent fasting, as alternatives to daily caloric restriction. The main focus is on a diet that mimics fasting, its development, and its impact on health markers and potential for disease prevention. The research involves clinical trials and studies on animal models to assess the effectiveness of fasting-mimicking diets. The article highlights the challenges of dietary interventions and the need for more practical approaches to achieve the benefits of caloric restriction.
Key Findings & Statistics
- In the study, participants aimed to decrease daily calories by 25%, but they only achieved a 12% reduction despite intensive dietary and behavioral counseling.
- Caloric restriction has been shown to extend the healthspan and lifespan of some strains of rodents by roughly 20% to 50%.
- In a 2011 NIA-cofunded study of young overweight women, a weekly fast (5 days of unrestricted eating and 2 consecutive days of 75% caloric restriction) produced outcomes similar to daily caloric restriction.
- In a phase 2 trial, published earlier this year in Science Translational Medicine, less severe energy restriction could provide bigger improvements with fewer fasting days per month. Dieters only had to restrict their calories 60% for 5 consecutive days a month over 3 months to get the benefits of the fasting-mimicking diet.
- Mice on the diet lived an average of 11% longer than control mice, which is 28.3 months versus 25.5 months and also had fewer cancers, less inflammation, less visceral fat, slower loss of bone density, and improved cognitive performance.
- In the study, Longo also tested the diet in a small pilot clinical trial. After 3 monthly cycles of a 5-day fasting-mimicking diet, the 19 generally healthy participants in the intervention group reported no major adverse effects.
- The intervention group reported decreased risk factors and biomarkers for aging, diabetes, cardiovascular disease, and cancer compared with the control group.
- In the new study, the control group was crossed over to the dieting intervention after 3 months. In the end, 71 participants completed 3 consecutive cycles of the diet.
- About a week after the end of the third cycle in the randomized arm of the study, the intervention group had lost an average of approximately 6 pounds, while the control group had not lost weight.
- Dieters also had less trunk and total body fat, smaller waist circumference, and lower blood pressure and insulin-like growth factor 1 (IGF-1) levels compared with the control group.
Other Important Findings
- The second phase of the CALERIE 2 trial demonstrated that it is feasible for humans to limit calories for an extended period. Participants who cut back on calories lost weight and kept it off for the duration of the study.
- Participants who cut back on calories showed improvements in blood pressure, cholesterol, and insulin resistance—all risk factors of age-related diseases.
- Scientists are exploring fasting-based analogues to daily caloric restriction, such as time-restricted feeding, alternate-day fasting, intermittent fasting, and periodic prolonged fasting.
- The fasting-mimicking diet, developed by Valter Longo, involves a 5-day meal plan with approximately 1100 calories on day 1 and around 750 calories on days 2 through 5. It is low in proteins and carbohydrates and rich in healthful fats.
- The diet appears to help more those who need it the most. Its effects on blood pressure and IGF-1 levels, as well as on body mass index and fasting glucose, triglycerides, total and LDL cholesterol, and C-reactive protein levels, were more pronounced among those who started the study with worse numbers.
- In the study, participants who entered the trial with prediabetes had fasting blood glucose levels in the normal range by the end of the intervention.
- Fasting shrunk the rodents’ kidneys, hearts, and livers, but the refeeding period appeared to kick start regeneration, increasing bone marrow-derived stem cells and progenitor cells and returning organs to normal weights.
- Longo published a mouse study in Cell that may begin to explain the process, at least in the pancreas. Six to 8 cycles of alternating a 4-day fasting-mimicking diet with a normal diet restored insulin-producing ß cells and insulin secretion in diabetic mice, reducing their fasting blood glucose levels to almost normal levels.
- Increased expression of certain protein markers suggested that mice on the diet had greater numbers of pancreatic progenitor cells, which resulted in the generation of fully functional ß cells.
- Based on promising results in mouse models of multiple sclerosis and humans with the disease, Longo also wants to test the diet in patients with autoimmune disorders.
Limitations Noted in the Document
- The study notes that the initial goal of the caloric restriction study was a 25% reduction in calories, but participants only achieved a 12% reduction.
- The article acknowledges the practical challenges of lifelong caloric restriction.
- The study highlights that participants in the CALERIE 2 trial might have had better results had they achieved a full 25% reduction in calories.
- The article notes the potential limitations of the fasting-mimicking diet, as it is not ready for use in patients being treated for type 1 or type 2 diabetes because combining a fasting-mimicking diet with blood glucose-lowering drugs could cause hypoglycemia.
- There was a higher percentage of dropouts in the fasting group, as seen in a weight-loss study comparing alternate-day fasting with daily caloric restriction.
Conclusion
The article concludes that the research suggests the efficacy of fasting-mimicking diets in promoting health and longevity. Scientists are actively seeking practical approaches to achieve the benefits of caloric restriction. The focus on fasting-based analogues, such as time-restricted feeding, intermittent fasting, and periodic prolonged fasting, reflects a shift towards more manageable dietary interventions. The research underscores the importance of finding practical methods to extend lifespan and improve health. The implications of changing diet to regenerate beta cells are revolutionary. The article suggests that more extensive and diverse trials are needed to fully understand the potential limitations of the diet. The fasting-mimicking diet is commercially available as a 5-day meal plan; however, Longo cautions that it is not yet ready for use in patients with diabetes and is working with diabetes experts to address safety concerns before launching a phase 3 multicenter trial. The success of Longo’s pioneering studies is likely to trigger more trials of dietary interventions linked to caloric restriction. As Verdin states, “This is just the beginning.”