From the Guidelines
Going 24 hours without food can be healthy for many people when done occasionally and properly, as long as they are healthy adults without underlying medical conditions, and it is done under the right circumstances and with proper precautions. For healthy adults, a 24-hour fast is generally safe and may even provide benefits such as improved insulin sensitivity, cellular repair processes called autophagy, and potential weight management 1. However, fasting is not appropriate for everyone, particularly those with diabetes, eating disorders, pregnancy, breastfeeding, or certain chronic conditions, who should avoid fasting without medical supervision 1.
When considering fasting, it's essential to stay well-hydrated with water, herbal teas, or other non-caloric beverages, and to break the fast with small, easily digestible meals rather than large portions. If severe dizziness, weakness, confusion, or other concerning symptoms occur during a fast, it's crucial to eat something and consult a healthcare provider. The body can typically use stored glycogen and then fat reserves for energy during a 24-hour period without food, which is why most healthy people can tolerate this duration without negative consequences 1.
Some key points to consider when fasting include:
- Staying hydrated to prevent dehydration
- Breaking the fast with small, easily digestible meals
- Avoiding fasting if you have certain medical conditions or are taking medications that require food
- Consulting a healthcare provider if you experience any concerning symptoms during a fast
- Being aware of the potential risks and benefits of fasting, particularly for individuals with diabetes or other chronic conditions 1.
It's also important to note that the safety and efficacy of fasting can vary depending on individual circumstances, and it's always best to consult with a healthcare provider before starting any new fasting regimen, especially if you have any underlying health conditions or concerns 1.
From the Research
Fasting and Health
- There is no direct evidence in the provided studies to suggest that going 24 hours without food is healthy or unhealthy 2, 3, 4, 5, 6.
- The studies primarily focus on the effects of metformin and lifestyle interventions on mortality and diabetes prevention, rather than the impact of fasting on health.
- However, some studies suggest that metformin, a commonly used medication for type 2 diabetes, may have benefits beyond glycemic control, such as reducing mortality rates 6.
- It is essential to note that the studies do not investigate the specific effects of fasting on health, and more research is needed to determine the potential benefits or risks of going 24 hours without food.
Metformin and Mortality
- A prospective cohort study found that metformin use was associated with an 18% reduction in all-cause mortality and a 25% reduction in cardiovascular mortality in patients with type 2 diabetes 6.
- Another study found that metformin did not influence mortality from all causes, cancer, or cardiovascular disease compared to placebo 3.
- The evidence suggests that metformin may have benefits beyond glycemic control, but the relationship between metformin and mortality is complex and requires further research.
Lifestyle Interventions and Mortality
- A study found that lifestyle modification did not impact all-cause, cancer, or cardiovascular disease mortality rates compared to placebo 3.
- Another study found that metformin compared to intensive diet and exercise did not reduce or delay the risk of type 2 diabetes 2.
- The evidence suggests that lifestyle interventions may not have a significant impact on mortality rates, but more research is needed to fully understand the relationship between lifestyle interventions and health outcomes.