Why agricultural humans need to mimic the eating and non-eating patterns of hunter-gatherers.
For hundreds of thousands of years, our hunter-gatherer ancestors ate food only intermittently. When they killed a large animal, the tribe feasted for days, when they didn’t, they might go a day or two without eating much or anything at all.
In the modern world, it is almost inconceivable for people to skip more than one meal. While we might think of it as a great advantage, our continual supply of calories actually comes along with many disadvantages.
Mark Mattson, a neuroscientist at the National Institute on Aging and professor at Johns Hopkins University, says our bodies need occasional breaks from eating for optimal health.
Intermittent fasting boosts brain function, wards off Alzheimer’s and Parkinson’s and makes us live longer by speeding up the regeneration of our cells, Mattson says in Ted Talk titled Why Fasting Bolsters Brain Power below.
“It’s been known for a long time that one way to extend the lifespan of laboratory animals is simply to reduce their [calorie] intake,” he says.
The lifespan of lab rats has been increased by up to 40 percent by feeding them less. Mattson suggests humans could do the same by adopting a lifestyle of intermittent fasting.
“We started looking at the effects of energy restriction on the brain in the context of age-related neuro-degenerative disorders and found we could slow down … Alzheimer’s and Parkinson’s,” Mattson said.
Mattson said fasting improves brain function by challenging it. “Your brain responds to the challenge of not having food by activating pathways that help it cope with stress and resist disease.”
Like vigorous exercise, intermittent fasting promotes neuron growth, strengthens synapses and increases production of new nerve cells. Fasting also increases the number of mitochondria in nerve cells, which improves cognition, memory and mood, and increases the ability of nerve cells to repair DNA, he says.
When you fast, your metabolism shifts so that you start burning fats, he explains. “Every time you eat a meal the energy is stored your liver in the form of glycogen [sugar]. That’s always tapped into first. It takes 12 hours before you deplete the glycogen stores in your liver.”
“When you eat three or four meals a day you never deplete the glycogen stores in your liver. You can’t start burning fat until those stores are depleted.”
When you burn fats you produce ketone bodies, which are very good for your brain, he says.
Fasting makes sense from an evolutionary perspective, Mattson says. “Our hunter-gatherer ancestors would not have survived unless their brain was functioning at a high level when they were hungry. If you’re hungry and haven’t found food, you better figure out how to find food. You don’t want your brain to shut down.”
This may explain why nerve cell circuits become more active when we’re hungry.
Director of USC Longevity Institute Valter Longo‘s research has led him to similar conclusions.
In his own Ted Talk called Fasting: Awakening Rejuvenation From Within, he explains how fasting triggers the body to regenerate itself.
It started with the discovery that fasting protects mice against the damaging effects of chemotherapy. After six sessions of chemo, only the mice who fasted were able to restore their white blood cell count back to normal, Longo said.
Longo and his fellow researchers wondered how this was possible.
“We started thinking about regeneration. Is it possible that fasting is telling the body to generate new cells and regenerate the immune system?” Longo asked himself.
Source: Return to Now