Fasting After 70: Benefits, Risks & Practical Advice
Intermittent fasting may improve blood glucose, insulin resistance, and weight management. But for people in their 70s and 80s, the benefits must be balanced against the importance of maintaining muscle, strength, and adequate nutrition.
The goal is better metabolic health—not simply fasting longer.
Why Age Makes a Difference
As we age, we gradually lose muscle mass and may become less efficient at building new muscle.
This makes adequate protein intake and resistance exercise particularly important.
Long fasting periods can make it difficult to eat enough calories and protein, especially for people who are already lean.
Losing weight is not necessarily beneficial for an older adult who is already at a healthy weight.
How Long Should We Fast?
There is no established ideal fasting schedule for older adults.
A reasonable approach for some people is a 12-hour overnight fast, such as finishing dinner at 7 p.m. and eating breakfast at 7 a.m.
Some people may comfortably extend this to 13 or 14 hours. However, research has not established whether longer fasting periods provide additional benefits for healthy older adults.
More restrictive schedules, such as 16:8, may make adequate nutrition harder to achieve.
Longer fasting is not necessarily better.
Protein and Muscle Preservation
Older adults often need more protein than younger adults to maintain muscle.
Many experts recommend approximately 1.0–1.2 grams of protein per kilogram of body weight daily for healthy older adults, with individual needs varying.
Spreading protein across meals may help support muscle maintenance.
Resistance training is particularly important because adequate protein alone may not prevent age-related muscle loss.
For older adults considering fasting, adequate protein and strength training should take priority over extending the fasting window.
For more information, see Protein, Creatine & Maintaining Muscle as We Age.
Who Should Be Especially Careful?
Fasting may be inappropriate or require medical supervision for people who:
Are underweight, frail, or losing weight unintentionally.
Take insulin or diabetes medications that can cause low blood glucose.
Have a history of eating disorders.
Have significant medical conditions or difficulty maintaining adequate nutrition.
Dehydration, dizziness, weakness, and medication-related problems can become more consequential with age.
Does Fasting Help Prevent Alzheimer's?
Fasting may influence insulin sensitivity, ketone production, and other processes associated with brain health.
Researchers including Mark Mattson and Dale Bredesen have explored these connections.
Whether fasting can help prevent Alzheimer's disease remains uncertain. Human research is still limited, although findings from animal studies and research on metabolic health provide reasons for further investigation.
For brain health, regular exercise, good sleep, blood pressure control, and management of metabolic risk factors have stronger supporting evidence.
A Practical Approach
For older adults interested in fasting, a moderate approach may be most appropriate:
Avoid unnecessary late-night snacking.
Consider a comfortable overnight fasting interval.
Eat sufficient protein and nutrient-dense foods.
Include regular resistance exercise.
Monitor weight, strength, and energy levels.
Discuss substantial fasting changes with a healthcare professional when medications or medical conditions are involved.
The best eating schedule is one that supports metabolic health while preserving strength, energy, and independence.
The Bottom Line
Intermittent fasting may benefit some older adults, particularly those with excess weight or insulin resistance.
But evidence specifically involving people in their 70s and 80s remains limited.
For healthy aging, preserving muscle, maintaining adequate nutrition, and staying physically active are better-established priorities than prolonged fasting.
Learn More
Research on preserving muscle mass and strength through adequate protein and resistance training.
Reviews the potential metabolic benefits of fasting and the limitations of current evidence.
Expert recommendations on protein intake for older adults.
Health Curious provides educational information, not individualized medical advice. Older adults should discuss fasting with their healthcare professional if they have significant medical conditions, take medications that affect blood glucose, or are at risk of malnutrition.