Aside from the unhealthy, processed nature of much of today's food, one such problem is that, having escaped the fasting part of the endless feast and famine cycle, we've also sidestepped our natural maintenance window. Because it was within the periodic fasting times that our body would switch from consumption mode of incoming food into burning stored fat (ketosis) and cleaning and repair mode (autophagy).

Just as the year has a cycle (spring, summer, autumn, and winter), we also have our own cycles, such as our breathing cycle. We inhale oxygen, spread that goodness around the body, and then exhale the carbon dioxide waste. Similarly, our cells have a cycle; they have an inhale (building phase) and an exhale (extraction phase).

With plentiful incoming food, the cells' focus is on building—on using the abundant material the body has available at that time. Then, when the good times stop and food is scarce, the body switches over to "exhale," the building pauses, and the focus switches to clean-up and maintenance. In time, food is resumed, and the body switches into consumption-digestion-building mode again.

Just as we're either breathing in oxygen or exhaling carbon dioxide—we can't do both at the same time—so it is on the cellular level. Therefore, as we no longer have days without food naturally, we need to periodically fast to allow our cells the opportunity to clean themselves

Another important reason autophagy doesn't just activate automatically when there's maintenance work to be done relates to energy.

Strict energy management is necessary for life to survive in the hyper-competitive natural world. The more energy an organism needs to run its 'machinery', the more precarious its survival. As a result, many bodily functions have evolved to use secondary energy sources. For example, when we exercise, our bodies shake and jar, and this free "pendulum" energy, along with muscle contraction, is used by our lymph fluids to circulate and do their work. It uses this 'free' energy rather than requiring an energy-demanding pump, as our blood requires. We'd need more energy to power an extra "heart," so we've evolved a way to power the lymphatic system at no extra energy cost, given that in the past humans were all very active. Obviously, we can't rely on movement to circulate our blood, or we'd die the moment we fell asleep, but less time-critical tasks can be done whenever our bodies happen to be in the right state. It doesn't really exactly matter when these tasks are done; what matters is that they are done every now and then.

If our vehicle is due for its yearly oil change and service in June, it doesn't matter if it's not done until July or even November. We can wait for a convenient time, and it's the same with many of our bodily mechanisms.Obviously, for most of us today, that right time never arrives.

During our ancestors natural down times, such as a storm that kept them inside their cave or shelter for a week, they would recline, relax, and wait till the storm passed before venturing out to gather food. No big deal; fasting for a week or so is no problem. But it was these involuntary fasts, during which their bodies got a break from their normal digestive chores, that triggered autophagy to ramp up to high intensity and tackle the backlogged cleaning and maintenance work.

When our autophagy mechanism swings into action, it starts cleaning out debris from within our cells. This swept-up trash is divided into three main groups and dealt with differently: Toxins are exported from the body because they’re not good for anything. Cellular components that are old or corrupted (such as misfolded proteins) are burned for energy, while components that are still in good condition are recycled into new cells.

Understood in an evolutionary context, this all makes sense: the body switches to clean and renovate mode when it has the surplus energy available to do so (not having to digest food) and when much of the swept-up debris can be burned for needed energy.

Clearly, as it's fasting that initiates both ketosis and autophagy, and because we need to fast for around 24 hours before they've ramped up to high intensity, we need to do multi-day fasts. Autophagy keeps operating at high intensity until its work is done (typically 3 - 5 days) and then returns to its low background level if that process is not interrupted with food.

So, while autophagy is somewhat inconvenient, the reality is that we cannot detox without fasting. Our bodies are as they traditionally were, and so traditional detoxes work now just as they always have. There are no short cuts, and why reinvent the wheel? But where there's money, the marketing people are around, which is why we can sometimes see 'detoxes' that are 'reinventing the wheel' and either ignoring autophagy completely or redefining it into something more convenient.

Below are some articles and YouTube videos that explain autophagy better, and in much more detail, than I have here.

Resources.

https://www.spartanmedicalassociates.com/fasting-and-autophagy/

https://draxe.com/health/benefits-of-autophagy/

Good and short you tube videos.

https://www.youtube.com/watch?v=AKzfb3d3Zt

https://www.youtube.com/watch?v=_czOxHKx6Og

Major health benefits of Autophagy 4 min video

https://www.youtube.com/watch?v=10jNZleNH9w

Autophagy expert. 4 min

https://www.youtube.com/watch?v=GCNY0a3gaeQ

Longer one by holistic doctor - 20 min

https://www.youtube.com/watch?v=XCvUf9WU4qI

What happens when we fast for 5 days ?

https://www.youtube.com/watch?v=Wzmacu2TgFg