Summary

Fasting can offer health benefits for older adults (60+), such as improved metabolic health, weight loss, and better cardiovascular markers. However, long-term fasting (>24 hours) poses significant risks, including nutrient deficiencies, muscle loss, hypoglycemia, and dehydration. These risks are particularly concerning for older adults due to age-related physiological changes like sarcopenia and impaired glucose regulation.

Intermittent fasting (IF) (e.g., 5:2 or alternate-day fasting) and time-restricted feeding (TRF) (e.g., 16:8) are generally safer alternatives that can improve insulin sensitivity, lipid profiles, and blood pressure. Overnight fasting (12-14 hours) is well-tolerated and aligns with natural circadian rhythms, offering modest metabolic benefits.

Older adults should consult healthcare providers before starting any fasting regimen to ensure it aligns with their health status and nutritional needs.

Introduction:

Fasting has gained significant attention for its potential health benefits, including weight management, improved metabolic health, and longevity. However, the effects of fasting in older adults (60-70+) require careful consideration due to the unique physiological changes associated with aging. This review will cover various types of fasting, their definitions, potential benefits, and risks for older adults, supported by clinical data from available biomedical literature.

Types of Fasting

1. Long-Term Fasting (>24 hours): Fasting periods longer than 24 hours, often lasting several days.
2. Time-Restricted Feeding (TRF): Eating is confined to a specific time window each day (e.g., 6-12 hours), with fasting outside that window.
3. Intermittent Fasting (IF):
   • 5:2 Method: Eating normally for five days and restricting calorie intake (~500-600 kcal) for two non-consecutive days.
   • Alternate Day Fasting (ADF): Alternating between days of normal eating and days of minimal calorie intake or complete fasting.
4. Overnight Fasting: A simple form of fasting where no food is consumed overnight, typically for 12-14 hours.

Physiological Considerations in Older Adults

Older adults are more vulnerable to the risks associated with fasting due to:

• Sarcopenia: Age-related muscle loss may be exacerbated by prolonged fasting or insufficient protein intake during eating windows.
• Metabolic Changes: Older adults often have impaired glucose regulation, increasing the risk of hypoglycemia during fasting.
• Bone Health: Prolonged calorie restriction or fasting can lead to bone density loss, increasing fracture risk.