Avoid or do less.
- Constant feeding…
What to do.
- Routinely:
- Time restricted feeding most interesting and practical (“FoundMyFitness — Satchin Panda“)
- Squeeze three meals into relatively short time period.
- Late breakfast, normal lunch, early dinner.
- Align with circadian rhythm.
- Provide fuel in the morning when needed.
- Reduce fuel intake at night when not needed.
- More or less, business as usual…
- Time restricted feeding most interesting and practical (“FoundMyFitness — Satchin Panda“)
- Periodic:
- Longer fasts.
- 3-5 days water-only fast.
- Material benefits of fasting and re-feeding cycling program.
- Ketosis and potentially autophagy.
- Longer fasts.
Three forms of nutrition restriction.
- Time restriction (when you eat).
- Caloric restriction (how much you eat).
- Diet restriction (what you eat).
Key Takeaways:
- Fasting and feeding are distinct programs within the metabolic cycle.
- Each part of the cycle has distinct benefits.
- Fasting activates a shielding and repair mode that we lost access to over time.
- Ancient program that has evolved for self-repair in times of famine.
- This program is no longer triggered due to constant feeding.
- Cycle of destruction (fasting) and reconstruction (feeding):
- Strengthen normal cells.
- Weaken (and consume) damaged cells.
- Daily time restricted eating may be the easiest to maintain.
- Eating in 4-12 hour window in sync with wake/sleep cycle.
- Likely to have modest benefits (weight control, better diet, less snacking).
- Periodic prolonged fasting may be most beneficial.
- Chance at robust cycling benefits: autophagy, shrinking organs, etc.
- Likely that 3 day fast is minimum period for achieving benefits.
- Practical considerations for longer fasts:
- Water only, maybe supplement with sodium (bouillon), sleep can be affected, likely feel colder, able to exercise (strength rather than endurance).
Three forms of nutrition restriction
- What you eat: dietary restriction (DR).
- Restricting some kind of macro-molecule (protein, carbs, fats).
- Figure out what you to restrict or avoid (eg, sugar, PUFAs, etc.).
- Figure out what to focus on: macro and micro (vitamins).
- Add supplements if/when needed.
- When you eat: time restriction (TR).
- Restricting the window during which you eat.
- Daily:
- Avoid lengthy eating windows.
- Late breakfast, normal lunch, early dinner.
- Periodic:
- Long fasts (3-5 days water-only).
- How much you eat: caloric restriction (CR).
- Reducing the inputs.
- Don’t overeat.
- Generally, portion control.
- Specifically, match to goals (health, training, etc.)
- Potentially some rules of thumb to consider.
- Grams of daily protein, fists of veggies, etc.
Fasting = time restriction.
- Traditionally involves focus on nutrient composition and caloric intake to optimize diets.
- Food provides energy and nutrients.
- Necessary to sustain life and allows growth, repair, and reproduction.
- Proper nutrition can influence health and survival / onset of chronic diseases.
- Emergence of focus on fasting: adjustments of meal size and frequency.
- Periodic absence of energy intake appears to improve multiple risk factors.
- Tool to ameliorate and postpone the onset of disease and delay aging.
- Underlying physiological processes of fasting involve:
- Periodic shifts of metabolic fuel sources.
- Promotion of repair mechanisms.
- Optimization of energy utilization.
- Shown to have positive effects on ageing and age related diseases across different animal models.
- Questions about applicability to humans.
- Animals have vastly different metabolic cycles – for instance, in relatively short fasts, mice loose up to 20% of their body weight.
- Different fasting protocols vary in time fasted and caloric intake.
- Common denominator of various types is initial suppression of IGF-1 pathway.
- Fasting protocols that are the most effective and maintainable:
- Prolonged fasting and fasting mimicking diets.
- These types trigger cycles of destruction and renewal:
- System is reset to a more youthful state, including lower inflammation.
- Shown to impact systemic inflammation, blood glucose levels and other ageing biomarkers.
- Potential to use fasting protocol as complementary therapy in cancer and other diseases.
Fasting and feeding are distinct programs within the metabolic cycle.
- Fasting and feeding are two different programs.
- Fasting: shielding and repair mode.
- Fed: grow and reproduce.
- Fasting activates a shielding and repair mode that we lost access to over time.
- Ancient program that has evolved for self-repair in times of famine.
- This program is no longer triggered due to constant feeding.
- We do not know why the repair mechanism happens only during the period of fasting.
- Likely: some genes are involved in both repair and nutrients signaling.
- Can’t do both at the same time.
- Also highlights that during time of fasting, energy has to come from different source:
- Protein (gluconeogenesis).
- Fat (oxidation), producing ketone bodies.
- Ketone bodies.
Each part of the cycle has distinct benefits.
- While fasting:
- Low IGF-1
- Triggers temporary destruction of white blood cells (autophagy, apoptosis).
- Shrinking of the organs.
- Triggers activation of (hematopoietic) stem cells (needed to replenish white blood cells).
- In effect, recycling the immune system.
- While re-feeding:
- High IGF-1.
- Triggers proliferation of stem cells.
- Regrowth of organs, healthy cells.
Resulting in differential stress resistance (strengthen normal cells, weaken damaged cells).
- Cycling strengthens normal cells, weakens damaged cells.
- Healthy cells:
- Starving the system triggers a cell’s “resistant mode”.
- This limits the impact on healthy cells of potential other toxics (from chemo or other therapies).
- Weak (cancer) cells
- Are used to a high nutrient environment.
- Lack of nutrients (especially protein, glucose) forces cells to use fat instead.
- The use of fat triggers the release of Reactive Oxygen Species (ROS), which cancer cells can’t handle. (anti-Warburg effect).
- Net effect is weakening of cancer cells for further destruction by standard of care therapies (chemo, etc.)
- Also makes cancer cells easier to detect by the immune system.
Types of fasting: caloric restriction (CR):
- 20-30% reduction in calories, no restriction on feeding times.
- Known for >100 years to have beneficial effects.
- Major drawbacks:
- Very difficult to maintain.
- Substantial side effects: weakened immune system prolonged wound healing, bone thinning.
- Lowers all markers indiscriminately, regardless of where you start; so if markers are good / normal, lowers them further to “below healthy”.
- Does not achieve dual benefits of fasting and re-feeding cycles.
Type of fasting: time restricted eating (TRE):
- Eating in 4-12 hour window in sync with wake/sleep cycle.
- Notion that the timing of feeding and triggering the fasting response matters – importance of:
- The amount of time spent eating during each day.
- Timing of food consumption relative to circadian rhythm.
- Try to sync with evolutionary evolved patterns (when did we have access to food, wake/sleep cycles).
- No specific dietary intake restrictions (ie, no restrictions on what to eat).
- Makes it easier to maintain than caloric or other dietary restrictions.
- Still likely to have positive impact on diet (likely to skip late nights snacks, alcohol, etc.).
- Highlights importance of syncing body circadian clocks and metabolic pathways.
- Many DNA repair pathways are time sensitive (ie, more active at night).
- Insulin sensitivity is lower at night (melatonin inhibits insulin secretion in the pancreas).
- Relevant for intake of food, as well as meds / supplements, surgery.
- Key benefits:
- Increased lean muscle mass, decreased fat mass, increased endurance [mice].
- Mild ketosis [mice].
- Cardiovascular health (less mitochondrial damage, improved protein folding) [fruit flies].
- Microbiome (more diverse bacteria, less acid reflux, improved bile acid function, lower cholesterol) [mice].
- Lower inflammation (less leaky gut issues through better gut repair, lower blood sugar through less eating when insulin sensitivity is low).
Types of fasting: intermittent fasting (IF) and prolonged fasting:
- No or few calories are consumed for periods of time that range from one to several days.
- Intermittent fasting:
- Restricts both eating time and calorie intake.
- Various types:
- 12+ hours fasting/day
- 2 day lower calories / 5 day normal.
- 1 day a week fast.
- Achieves modest cycling benefits.
- Mainly triggers ketosis, weight loss.
- Ignores importance of timing of meals with circadian rhythms.
- Prolonged fasting
- 3-5 day or longer water fasts.
- Difficult to maintain, especially for non-healthy individuals.
- Achieves robust cycling benefits.
- Autophagy, apoptosis, organ shrinking.
Types of fasting mimicking diet (FMD):
- Created to try and make fasting more acceptable/doable.
- Low-carbohydrate, high-fat diet.
- for 5 days periodically.
- Low protein, low sugar, vegan, lots of “good fats”.
- About 800 calories a day in total.
- Enhances compliance by avoiding complete deprivation of food.
- Simulates effects of prolonged fasting.
- Sample 5-day diet:
- Day 1 – 1,090 calories (10% protein, 56% fat and 34% carbohydrate).
- Days 2 through 5 – 725 calories (9% protein, 44% fat and 47% carbohydrate).
- Also achieves robust cycling benefits.
Sources and links:
- “A Time to Fast“, Andrea Di Francesco, Clara Di Germanio, Michel Bernier, Rafael de Cabo, Science 16 Nov 2018: Vol. 362, Issue 6416, pp. 770-775.
- FoundMyFitness — Valter Longo
- The Drive with Peter Attia — Rhonda Patrick
- The Drive with Peter Attia – AMA #11 – All Things Fasting
- My Nutritional Framework – Peter Attia
- The Drive with Peter Attia – AMA #11 – Strategies for Longevity
- Wikipedia