Fasting triggers the body's ability to clean and renew its own cells, a process known as autophagy. But fasting isn't easy for everyone, and some newer research [1] suggests it may not be as universally healthy as once thought.
In short: Fasting is one way to trigger autophagy, but not the only one. Spermidine and spermidine-rich foods, a ketogenic diet, intense exercise, and good-quality sleep can all support autophagy, the body's cellular renewal process. This makes it possible to encourage cellular clean-up without fasting.
As someone with hypothyroidism, I have never found fasting easy. In my experience, fasting with hypothyroidism can leave the body behaving as though it is entering a sustained period of starvation. In response, it tries to protect survival by down-regulating metabolism and making it harder for bioavailable T3, one of our key thyroid hormones, to attach to receptors in our cells. At the same time, the adrenal glands can increase cortisol production to help regulate blood sugar, which over time may contribute to inflammation and reduced melatonin production. That extra cortisol is also made in part from progesterone, a hormone that supports sleep and helps balance estrogen.
You can probably see why some of us are highly motivated to find ways to trigger autophagy without having to fast.
How to trigger autophagy without fasting
There are several evidence-supported ways to encourage autophagy that don't involve fasting: certain supplements and foods, a ketogenic diet, intense exercise, and quality sleep. Here is how each one works.
Spermidine: supplements and foods
Have you heard of spermidine? Spermidine is a natural polyamine that the body produces (with help from the gut microbiome) and that, like autophagy itself, tends to decline as we age. The good news is that we can also get it from spermidine-rich foods such as Japanese fermented natto, tempeh, mature cheddar cheese, and food-derived spermidine supplements. You can read more about what spermidine is on our pillar page.
Spermidine has been shown to induce autophagy [2] and acts as a calorie restriction mimetic, which means it may offer some of the cellular benefits associated with fasting, without the fast itself. Research also suggests it may act on many of the hallmarks of aging, the biological pathways through which the body ages [3].
Our premium, food-derived spermidine supplement, Primeadine, is made from concentrated Japanese wheat germ and offers a bioavailable way to increase your spermidine intake. It is rigorously tested for purity and potency in Japan and the USA. Some of the areas people look to spermidine to help support include:
- Hair growth, quality, and thickness (including lashes and brows)
- Healthier nails and skin
- Deeper, better-quality sleep
- Cognition and mental clarity
- A greater sense of vitality
- And the cellular renewal you can't see or feel directly, but that supports the rest
(These describe areas of interest and reported experience, not guaranteed outcomes. Spermidine is a food-derived nutrient, not a treatment for any condition.)
The ketogenic diet
A ketogenic diet, where roughly 75% of calories come from healthy fats and 5 to 10% from carbohydrates, is another way to encourage autophagy [4].
Healthy fats include extra virgin olive oil (EVOO), grass-fed ghee, grass-fed butter, and medium-chain triglycerides (MCTs) such as caprylic acid, or C8. These fats help keep you satisfied, and they provide ketones, which can supply a large share of the brain's energy needs.
If you think going keto sounds hard, here is a reassuring fact: you have already been in ketosis without noticing. We are all born in ketosis in the womb, and we remain in ketosis while breastfed.
Some research suggests that in Alzheimer's disease, the brain's ability to use glucose for fuel becomes impaired, while its ability to use ketones may be relatively better preserved.
Healthy fats such as olive oil and fish oil are my top choices. I personally love grass-fed ghee, which contains neither lactose nor the casein proteins (A1 and A2) that some people react to. One important caveat: some research suggests that people who carry one or two copies of the APOE4 gene variant may respond differently to saturated fat, with a possible link to neurodegenerative risk. If this applies to you, it is worth discussing your fat intake with a healthcare professional; olive oil and fish oil are generally gentler choices.
For recipes and more information, our friends at the KetoDiet blog are a good resource (no affiliation, just friends).
Exercise
Intense exercise is another way to trigger autophagy without fasting [5,6,7]. This doesn't mean running a marathon. You can get time-efficient results with resistance training and weights built into circuit-style workouts.
Here again, the Japanese have refined the approach with the Ka'atsu device, which uses blood flow restriction to build muscle and support growth hormone and nitric oxide in a short time. There are reported skin, hair, and nail benefits too, which is why some Japanese aestheticians use it in their treatments.
You can explore this via Ka'atsu Global or the Ka'atsu YouTube channel.
Another option is Dr. John Jaquish's X3 Bar, which combines your body weight with heavy-duty resistance bands attached to a metal bar designed to protect the weakest load-bearing point (in this case, the wrists). Many OsteoStrong bone-building clinics in the US also have them on-site and can often supply them.
Sleep
Sleep is another powerful way to support autophagy. Fragmented sleep has been shown to interrupt the body's ability to run autophagy properly [8]. Uninterrupted sleep gets harder as we age, which is one more reason to prioritize exercise (shown to improve sleep), wind down away from blue-light devices (which can keep cortisol elevated and suppress the sleep hormone melatonin), and protect the progesterone stores that also help us rest.
Beyond triggering autophagy, spermidine has also been shown to influence some of the clock genes that regulate our circadian rhythm. In line with this, some of our customers have reported increases in deep sleep on their wearable sleep trackers.
If deeper sleep and daily autophagy support both appeal to you, our food-derived Primeadine spermidine supplement is one simple way to work toward both.
This article is for educational purposes and reflects personal experience and general research; it is not medical advice. Please speak with a qualified healthcare professional before making significant changes to your diet, exercise, or supplement routine, particularly if you have a thyroid or other health condition.
References
1. 8-hour time-restricted eating linked to a 91% higher risk of cardiovascular death
https://www.sciencedaily.com/releases/2024/03/240320115727.htm
4. Emerging Role of Mammalian Autophagy in Ketogenesis to Overcome Starvation: https://www.ncbi.nlm.nih.gov/pubmed/27050461
5. Exercise and Exercise Training-Induce Increase in Autophagy Markers in Human Skeletal Muscle: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5889490/
6. Exercise Induces Autophagy In Peripheral Tissues and In The Brain: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3463459/
7. Exercise-Induced BCL2-Regulated Autophagy Is Required For Muscle Glucose Homeostasis: https://www.ncbi.nlm.nih.gov/pubmed/22258505
8. Circadian Rhythm of Autophagy Proteins in Hippocampus Is Blunted By Sleep Fragmentation: https://www.ncbi.nlm.nih.gov/pubmed/27078501
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