A physician explains why time-restricted eating is nature’s anti-aging diet[dropcap]N[/dropcap]o topic in the health sciences is more fundamental or more poorly understood than nutrition. How and what we eat now causes more disease and death than any other health risk factor. About half of all American adults have one or more preventable, diet-related chronic diseases. Our norm of three meals a day with snacks between is antithetical to our biology. Recent research suggests a new paradigm with remarkable effects on aging, disease, and weight control. It’s about time. Caloric restriction (CR), a dramatic reduction in caloric intake without malnutrition, has been shown to not only reduce weight but prolong healthy life span in a variety of species from worms to nonhuman primates. Risk for cardiovascular disease, diabetes, and cancer, the leading causes of death and disability, are markedly diminished by CR regimens. However, few people can tolerate deprivation, and calorie restriction is also associated with undesirable side effects such as fatigue, loss of libido, impaired cold tolerance, and muscle wasting. These obstacles drove a quest for a more user-friendly variation of CR. Valter Longo, at the University of Southern California (USC) Longevity Institute, was a pioneer in so-called fasting-mimicking diets. He demonstrated that five days of CR per month for three months caused beneficial changes in risk factors of age-related diseases in humans. Five days of CR, however, is still a tough ask for many — studies have shown that up to 30% of subjects attempting to comply with this regimen drop out. A big breakthrough came in 2012. Satchidananda Panda at the Salk Institute for Biological Studies found that mice fed a high-fat diet eight hours per day were healthier and leaner than mice allowed to eat the same diet whenever they wanted, even though both groups consumed the same number of calories. The key variable appeared to be defining a daily time frame for feeding and fasting, hence the name — Time Restricted Feeding (TRF). Panda then investigated this effect in humans under a variety of conditions that mimic the real world.
The team studied the impact of TRF in obese participants with diverse pre-existing diets (high fat, high sugar, high fat and sugar). TRF appeared to prevent elevated cholesterol, insulin resistance, and inflammation despite the consumption of obesity-causing foods. In other words, it seemed to block the pathological consequences of the eating habits of many Americans. The benefits were proportional to the fasting duration. The longer the fast, the greater the improvement in lipid profile, insulin sensitivity, and inflammation. Research that demonstrated how the benefits of CER (continuous energy restriction) could be gained by restricting food intake to certain times of day signaled the beginning of the Intermittent Fasting (IF) movement. IF diets are defined by the duration and frequency of the fast. Daily IF requires 12–16 or more hours without eating. In alternate-day fasting (ADF), one alternates between zero calorie consumption one day and unrestricted feeding the next. A middle ground IF, alternate-day modified fasting (ADMF), entails alternating between a day of consuming few calories (<25% of energy needs) and eating without restriction the next. These IF regimens have been shown to trigger many of the same biological pathways as caloric restriction. How could this scheduled eating regimen have such profound effects? It appears two key components are at play. Flipping the Metabolic Switch The body can use either glucose or fatty acids for fuel. After eating, glucose provides energy and unused glucose is stored as glycogen, an easily mobilized form of glucose. In the absence of long or intense physical activity, glycogen is not depleted and unused glucose is converted to triglycerides and stored in fat tissue. Fasting works by first emptying the glycogen stores and then tapping fat tissue. Triglycerides are broken down to produce fatty acids. The liver converts these fatty acids to ketone bodies that can be used as fuel. Ketone levels begin to rise after eight to 12 hours without food. Like a car’s fuel gauge that only flashes when approaching empty, the time needed to flip the metabolic switch depends on the starting liver glycogen content (fuel in tank) as well as energy expenditure during the fast (how fast you drive). This metabolic switch from glucose to ketone utilization activates evolutionarily conserved cellular responses that improve glucose regulation, increase stress resistance, and suppress inflammation. During a fast, damaged molecules are repaired or removed. This has been shown to improve or prevent a wide range of disorders including obesity, diabetes, cardiovascular disease, cancers, and neurodegenerative brain diseases. It is striking that both physical and mental function is improved with IF. Endurance, coordination, and balance are increased and muscle mass is maintained despite the regular period of fasting. Ketones allow greater energy production and appear to increase the generation of mitochondria. Ketones also boost levels of brain-derived neurotrophic factor, a protein essential for maintaining healthy neurons and creating new ones. Spatial memory, associative memory, and working memory are all enhanced by IF. The fact that a period of food deprivation flips a metabolic switch that enables superior functioning makes sense from an evolutionary perspective. As hunter-gatherers, we did not have breakfast before going out in search of food. Our most important activities for survival were carried out on an empty stomach. Persistence hunting consisted of long periods of moderate effort punctuated by short bouts of maximal sprints. Gathering required precise memory for identification of nourishing and poisonous plants. The contemporary cultural norm of three meals per day with snacks eliminates the possibility of this higher level of function. Humans have lived as hunter-gatherers for 99% of our existence. Our physiology is the result of millions of years of adaptation to periods of food scarcity during which superior cognitive and physical performance conferred survival. We now know that our feeding habits not only impair our fitness but fuel an epidemic of chronic disease. Time of Day The second aspect that matters is when you eat and when you fast. Recent discoveries have shown that a meal consumed at 8 a.m. is not processed the same way as an identical meal consumed at 8 p.m. All mammals possess this metabolic circadian rhythm (changes that follow a 24-hour cycle driven by environmental light and darkness) for good reason. Energy requirements are defined by activity level. The human day (until recently in our history) consisted of an active daylight phase and a resting night phase. This resulted in the evolution of a metabolic day shift, so to speak, bearing little resemblance to the night shift. Daytime metabolism was designed for eating, energy harvesting, and storage while nighttime metabolism was designed for fasting and accessing stored energy. Melatonin, the body’s expression of darkness, orchestrates these changes. Traditionally, melatonin was considered primarily as a sleep cue. It is now recognized as the most powerful messenger to switch from active to resting metabolic function, a chemical signal of day’s end. Darkness triggers the secretion of this ancient hormone. Light, whether natural or artificial, blocks melatonin secretion. The widespread adoption of electric lighting ended sunlight-entrained human circadian rhythms. Illuminated night blocks our natural transition to a fasting state — and eating (acquiring and storing calories) now continues well into the night. Even dim light at night has been shown to significantly decrease melatonin secretion in humans. This disconnection from nature’s clock is now considered an important cause of our struggle with weight gain. Melatonin exerts its effect on weight by modulating the action of several key metabolic hormones such as insulin, ghrelin, and leptin. These hormones orchestrate appetite, satiety, calorie uptake, and fat storage. Melatonin also appears to increase activity level and core body temperature, thereby increasing energy expenditure. Investigators believe this increased calorie usage is due to activation of brown fat. Unlike white fat (most body fat) that stores energy, brown fat burns up lots of extra calories by producing heat. Animals that have had the pineal gland (location of melatonin production) removed become overweight. Timed administration of melatonin reverses the weight gain. In addition, middle-aged fat animals given melatonin and studied to old age showed decreased weight and visceral fat. These changes were eliminated if melatonin was withheld. Getting Started For most people (apart from diabetics for whom fasting could be dangerous and must be discussed with a physician), the major challenge around IF has to do with breaking established habits. Any departure from three meals a day with snacks between can feel like a major shock to the system. Switching to an IF regimen often causes intense hunger, irritability, and impaired concentration. However, side effects usually subside within a month. Elimination of all snacks is a good starting point, followed by gradually lengthening the time interval between dinner and the first meal of the next day. The goal is to fast for 16 to 18 hours per day. Your life, sourced by science. A new Medium publication about health and wellness. |
^3000US citizens have no real political representation.
We don't live in a democracy. And our freedom is disappearing fast.
I don't want to be ruled by hypocrites, whores, and war criminals.
What about you? Time to push back against the corporate oligarchy.
And its multitude of minions and lackeys.
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1 comment
More and more often I find evidence that fasting has actual health benefits. Interesting that, initially, fasting was done for religious reasons. This appears to be one more example of an activity that God suggested mankind ought to do, for their own good, but was often ignored or dismissed by modern western “thinkers” as superstition.
Of course, looking at the big picture, the advice given is common sense: don’t kill, don’t steal, don’t lie, don’t cheat … be kind to each other, take care of each other, take care of the poor, feed the hungry, care for the homeless, be loving and peaceful. All these things are obviously healthy and good things to do, but even these smaller things like fasting are proving truly to have been good healthy advice too.
Here is the way I see it. God created the world as an abundant and peaceful garden, and he set us humans up as the caretakers of this place. Then something happened. Somehow humankind began to do evil, to exploit and enslave fellow humans, and to exploit the earth. Humankind learned to use lies and deceit and violence to manipulate others and to exploit them. This began the struggle which we are to this day still engaged.
God looked down upon His creation, seeing the evil being committed here, and He endeavored to help us. He sent messengers to us, from among our own people, giving us advice for how to extricate ourselves from this mess. He began giving us advice, the advice already mentioned.
At first it was simple, ‘Stop killing each other’, ‘Stop lying and deceiving each other’, ‘Stop stealing from each other’. Then it became harder, ‘Love one another’, ‘Care for the poor’, ‘Seek justice for the oppressed’, ‘Do not be moved to anger, but forgive.’
All along God has been trying to help us out of this mess, this trap, that we have somehow fallen into. All along God has been trying to help us escape this violence which we are doing to ourselves. All along God has been trying to help us, and now, looking around the world, how do we repay him?
I look around the world and see selfish people who don’t care. They say, “Who cares about God? There probably is not a God, but even if there is, what difference does that make. I don’t care either way.”
What?! God, who created this beautiful world for us, who created the mountains and the trees and the oceans and the summer breeze, you don’t care about Him? The One who gave you a mother and father and sisters and brothers and friends and children and every good thing you love, you don’t care about him?
We are destroying this planet He made for us! We are killing each other with wars and engineered famines. We are allowing millions to go to bed hungry every night, and many more we allow to sleep outside without homes, meanwhile we watch our TVs and remain indifferent. We must wake up the truth!
Humankind, all those who do believe in God, the One God, creator of the Heavens and the earth, it is time we set aside our differences. It is time we came together. It matters not how we came to know God. Whether we are a Christian or a Jew, a Muslim or Hindu, it does not matter. We are the believers in God. We are brothers and sisters in one family, we are the children of God, we are the family of God, the greater family of God. It is time we came together.
So now, please, we must come together in love, and we must prepare to help our own brothers and sisters in God, for the world stands on the brink of destruction. We must set aside our differences and come together in the name of God who made us. We must pray that God saves us from destruction, which would be done by our own hands. We must beg forgiveness for ourselves and for all of humanity, which has gone beyond all bounds of reasonable action. We should pray that God will help us, that He will bring us together, into one family under God, that He might help us, and restore peace to this planet.
This is my plea, all you believers in God, come together, join me in prayer and repentance before God, our Almighty Creator, that He will have mercy on us and save us from our plight. Truly, He is our only hope.
I pray that God will bring us together, as one larger family, one family under God, a family of people dedicated to peace and love. I pray that God will help us to restore the earth to the way it once was, a healthy and abundant garden, that we might care for it and tend it, as we were meant to. I pray that we remember our blessings and praise God for what we had and what we have. I pray that all of us will remember God, our true source of strength and our only hope. I pray that God will unite us in Love that we might have peace among the nations and everywhere throughout the heavens and the earth.
This is my prayer, which I pray in the name of the Almighty God, the One God, creator of all the worlds. Amen.