Health Hack #28 - Time Restricted Eating
The 3 Ways Known to Extend Lifespan Across All Life Forms
Peppered into a prior Health Hack (Not All Calories Are Created Equal) was a staggering scientific truth. Across all life forms - from yeast all the way up to human beings - there are three hacks known to extend lifespan.
The first hack (in no particular order), and certainly the most obscure, is a compound called rapamycin. Rapamycin was discovered on Easter Island in the 1960’s, in soil bacteria. A naturally occurring compound, rapamycin is most known in the medical world as an immunosuppressant. When patients receive transplants - such as a new kidney - rapamycin is used to suppress the immune system and protect against rejection of the new organ. Immunosuppression has served as its most dominant use since its discovery, but rapamycin also possesses antifungal and antibiotic properties, and has been used successfully to these ends. It was not until the last 10-15 years that researchers connected some key dots with rapamycin, learning that it’s capable of helping to silence a key growth pathway known as Mtor. The discovery of the Mtor pathway was actually made via researching the effects of rapamycin supplementation, which is why its acronym is so direct: Mtor = Mammalian target of rapamycin. Inhibiting Mtor initiates a cascade of known longevity benefits, primarily that of autophagy. Autophagy (direct translation: “auto-eating”) is a process of natural cellular cleansing, where damaged cells are literally consumed and cleaned out, making way for the regeneration of healthier ones. At a cellular level, when the Mtor pathway is inhibited, we go through a mass cleansing process, improving and rebuilding the health of our very building blocks of life. Rapamycin supplementation is known to precisely inhibit this pathway. (Please note that rapamycin is not commercially available for supplementation, nor is it recommended. The sweet spot dosage jury is still out, and presumably will be for years to come. If and when it does hit the market for individual use, you can bet that it won’t take long before its name is no longer obscure.)
The second, and most easily understood, is caloric restriction. The premise here is simple. Seek to consume as few calories as possible while maintaining a moderate amount of lean muscle mass and maintaining Grade A blood panels, and you’re in a position to live longer than average. (The latter criteria of having provable good blood health undermines the notion that one can subsist on just a few Twinkie’s per day + a great deal of exercise; your micronutrient and mineral deficiencies would certainly drag you down.) Over-consume calories, and we keep a variety of anabolic (aka growth-inducing) pathways online for longer than our bodies would like. When we’re in a grow, GRow, GROW state, we’re less capable of silencing growth inducing pathways that could do us harm, such as the accumulation of adipose tissue and the proliferation of cancer cells. Caloric overload stimulates the Mtor pathway too aggressively. Interestingly, caloric restriction is quite difficult for many, yet it often comes as a natural consequence of the third and final hack, which is time restricted eating.
An Intro To Time Restricted Eating
The third hack, and the focus of this introductory article, is Time Restricted Eating. Time Restricted Eating (which we’ll refer to as TRE henceforth) is often interchangeably used with a phrase that readers are likely more familiar with, which is Intermittent Fasting. Technically speaking (in a traditional scientific research setting, pertaining to humans), intermittent fasting refers to periodic fasts that last longer than 24 hours. If once per month you engage in a 72 hour water only fast, you’re practicing intermittent fasting. This is very different from TRE. (But note that, due to it’s calorie restrictive qualities, it fits in with the framework of a longevity-focused approach to living and dieting. It’s also shown to suppress Mtor and kickstart the process of autophagy. It’s just not very practical or desirable for most.)
TRE, on the other hand, refers to a set duration of time when food is consumed. Within the health community it’s often referred to by the time split that one adheres to. Someone subscribing to an “18/6”, for example, would refrain from eating for 18 hours per day, and consume all of their calories within one 6 hour window, which is generally during the same 6 hour stretch each day.
TRE has longevity benefits across a few different spectrums. As alluded to above, caloric restriction comes much easier within a TRE framework. It’s a complete misnomer that by skipping breakfast, one will be compelled to consume twice the amount of food they normally do for lunch. Not true. As a matter of fact, the practice of daily TRE (especially when interspersed with occasional intermittent fasting) will actually cause your stomach to shrink, compelling fullness faster, and really putting that caloric restriction hack into practice.
TRE also works to naturally suppress the Mtor pathway. Not to the extent of intermittent fasting, but enough to noticeably turn the dial, if practiced routinely, ideally at a minimum 16/8 split (or one more stringent, such as an 18/6).
Interesting studies have revealed that all things equal, weight loss is much likelier when practicing TRE. If you take an individual’s standard daily diet and then force that individual to consume that identical diet within a compressed eating window, over time that individual is very likely to assume a lower body weight baseline over the non-TRE approach.
Like is true with so much about food science, what was once prescribed as the ideal TRE approach has since been turned on its head some. When TRE first rose to prominence (to us health geeks) about ten years ago, there was much poo-pooing about breakfast, arguing that despite the age old connotation that it was the most important meal of the day, it was actually completely needless. Therefore, the typical TRE in a 16/8 fashion would have a feeding window of something like 2-10pm. Skip breakfast, hit a late lunch, have a large dinner, don’t worry too much about late night snacking. This late PM approach is shown to be of tremendous benefit, in comparison to no discernible TRE practice.
Nowadays, more attention is being paid to beginning the window earlier. Insulin sensitivity is more likely improved when we can avoid eating close to bed. When melatonin (our sleep hormone) begins its production cycle (approximately 3 hours before we go to sleep), a message is sent to our pancreas. “Hey, we’re closing up shop, so you can start closing down your insulin production factory too.” Insulin is generated when we consume carbohydrates and need help in disposing of the glucose that the sugars are converted into. In the absence of insulin, or when insulin is dysfunctional and poor at its job (as in Type 2 Diabetes), our blood sugar levels remain elevated longer than they safely should, and we’re much more likely to see that glucose stored in fat cells.
One hack within a hack, if the later feeding window is more in line with your lifestyle and preferences, is simply to limit your carbohydrate intake towards the very end of the day. This way as the insulin factory begins shutting down, you’re less likely to need its help anyway.
As for an approach at trying it on for size, start simply. Creating a feasible goal that doesn’t leave you hungry and angry (hangry) can be a very simple stepping stone towards extending the window. Start with a 12/12. Breakfast at 8am, your last meal at 8pm. That shouldn’t seem too difficult. See if you can slowly condense that to a 16/8, taking one hour steps at a time, going 13/11, then 14/10, etc.; ultimately landing on an eating window of 10am-6pm, or even 1pm-9pm. Allow some elasticity as you wade the waters, and see what works best for you. Those older in age and those with young children have a tendency to have dinner earlier, allowing for a more natural progression into an early TRE window. Others may tend to work late and have other lifestyle forces that compel a later window. Again - find your own sweet spot. The moral of the story is that any personal sweet spot that’s a 12/12 split or better is bound to leave you better off than having no TRE practice whatsoever. And if TRE is not for you, then no worries. Maybe instead you can try some of our 27 other (and more to come) Health Hacks on for size - Health Hack Blog.