The 8-Hour Diet (9 page)

So it’s instructive that he calls the modern meal plan of three squares “abnormal from a genetic standpoint. We clearly haven’t adapted to it
yet.” And by “adapted,” he means that we’ve instead become sedentary, obese, prone to health risks, and at the mercy of fast-food advertising. Sounds like a recipe for extinction.

Dr. Mattson pulls out a fascinating set of maps that show the distances our species (or its ancestors) have traveled to find dinner over the course of our histories on the planet. The first map, from 5 million years ago, shows a dog-eat-dinosaur world where the species are constantly on the run, but cover only a limited distance. To survive long enough to reproduce, they’ve got to both outsmart and outrun all of the other critters that would like to eat them (or us) for dinner. Physical capacities and mental ones interlock; the species that have the best brains and endurance live the longest, have more offspring, spread their genes far and wide, and come to dominate the herd.

OK, fast forward to 10,000 years ago. A plucky mammal called homo sapiens is up on two legs and can sprint across the landscape for long distances—far outrunning even the most dogged competitor or pursuer. And for our species, this form of travel is broadening. The brains of these running animals expand because there’s so much to think about: where that big bear keeps his den, where the berries ripened last spring, where the water lasted longest during the summer drought. Their muscles grow and their bellies shrink in like measure, to make it easy for them to run to those places.

So you see how the combination of a lean belly and a big brain could increase the odds that you survived a long time and mated successfully. Who wouldn’t want to get busy with an animal like that?

And that’s just what the 8-Hour Diet can give you.

Dr. Mattson points at his map, studded with hazards and opportunities and showing an animal that can range far and wide to guarantee his survival. Skipping meals inspires the animal to peak efficiency, physically and mentally. That’s the world our bodies are genetically wired to thrive in. All of these marvelous mechanisms kick in to protect us from harm and increase our odds of thriving in a difficult environment when we trigger them with intermittent fasting.

The only bad news: We’re not living 10,000 years ago. We don’t need to remember where the wildebeests feed or the crocodiles roam. Today,
we need only remember how many paces there are between our cubicle and the vending machine.

On to Dr. Mattson’s last map, labeled, ominously, “Transition to the Sedentary/Overfed/Obese Phenotype.” This Google map of gluttony shows beings who are capable of traveling much farther distances, but it strips away the hazards and hunger and replaces them with Hardees and Five Guys. In place of healthy running figures, it swaps in a little jeep symbol, which stands for “effort-sparing technologies.” Plentiful food and little effort. You can probably guess what happens to the lean, healthy homo sapien.

In the upper left-hand corner of the map, Dr. Mattson has included a damning stat. The two previous maps featured animals that had a body mass index—a measure of fat—in the 19 to 24 range, enough to sustain us if a food shortage threatens, but not undermine our health in the long run. In the current age, that BMI figure balloons above 25 and threatens everything we hold dear: our looks, our sex lives, our health, our life expectancy.

And that’s why Dr. Mattson, one of the foremost anti-aging experts in the world, lives the kind of life he, and we, are genetically evolved to excel in. Here’s how he pulls it off: “The fast I’m doing: Skip breakfast and lunch and exercise instead, then eat a nice meal over dinner.”

Of course, Dr. Mattson gets paid to be his own guinea pig, and his is not a lifestyle that everyone would want to follow. But you don’t need to be anywhere near as rigorous to see the benefits of the 8-Hour Diet. He mentions two studies he did with groups of 21st century homo sapiens, intermittently restricting meals. One study was half a year in duration, another 2 months. “The only subjects who dropped out dropped out within the first 2 weeks,” Dr. Mattson says. “After 2 to 3 weeks they got to like the diet mainly because they started losing weight and started feeling better.

“It doesn’t matter which fast a person does,” he continues. “If they can do it and stick to it, they’re going to lose weight and their health is going to improve. I think the more healthy diets that are available to people, the more likely they are to incorporate one of them into their lifestyle.”

Reassuringly, it’s not as if he wants you to outlive your reasons for
living: “What we want to do is understand how we can help people live long lives without disease,” he notes. “Have less focus on extending maximum life span—not necessarily helping people live to 150.”

If you had to name your worst nightmare about aging, what would it be—aside from still wearing leather pants at age 63, like Gene Simmons of the once-popular group Kiss?

Right: It’s that you’ll descend into the mental fog of Alzheimer’s disease, slowly losing your cognitive powers, not recognizing your own spouse, your children, or your fellow aging ex-band members from the once-popular group Kiss.

Dr. Mattson shares that fear (except for the leather pants part). In fact, it’s why he got into anti-aging research in the first place. As a neuroscientist, he’s spent his entire career tracking the brain insults that lead to Alzheimer’s and Parkinson’s, which impair memory and movement in older people.

“One study had shown that that [intermittent fasting] will increase the life span of animals by about 30 percent,” he says. The lightbulb lit up: Fasting obviously had a salutary effect on the body, but what good was a healthy body without a healthy mind? Perhaps our brains are adapted the same way our bodies are—to last longer when we take in fewer calories.

So the NIA tested a group of laboratory mice, allowing half to eat all they wanted whenever they wanted, while the other half was fed only every other day. After 3 months, the researchers administered a neurotoxin to their mousey brains. The results were definitive: The fasting mice fended off the toxins and maintained brain function; the big feeders lost their minds.

What does this mean to you, exactly?

Well, in place of the neurotoxins Dr. Mattson administered to these mice, swap in the toxic amyloids now known to cause Alzheimer’s. When you fast, you increase production of proteins called
neurotropic factors
that are critical to learning and memory. They fend off brain attackers and clear the wreckage of dying cell structures, and they encourage the formation of new neurons and synapses.

To explain just how your brain grows stronger on the 8-Hour Diet, Dr. Mattson likens it to what happens to muscles when you work them regularly.

“Vigorous exercise is a stress on your muscle cells,” he points out. “There’s increased energy demand and increased free radicals, but it turns out to be good for your muscle cells as long as you’re allowed some recovery. That mild stress stimulates muscle cells to increase production of proteins that help the cells resist stress: antioxidant enzymes, protein chaperones, growth factors, increased mitochondrial production. The number of mitochondria increase. So there’s an increased ability to provide energy to the muscles.”

Then he winds up to deliver the kicker: “Many of the same exact changes that are happening in the muscle cells—increased antioxidant enzymes, increased protein chaperones, increased growth factors, increased number of mitochondria—are occurring in nerve cells with fasting.”

In other words, skipping meals is like exercise for your brain.

Dr. Mattson is talking about mental vigor here, but a study published in
Medical Hypotheses
, in 2006, extends the blanket endorsement of fasting to a whole range of debilitating conditions that can sap the life, and the joy of living, out of older people.

The study authors, Stanford-trained surgeons, write: “Since May
2003 we have experimented with alternate-day calorie restriction, one day consuming 20 to 50 percent of estimated daily caloric requirement and the next day ad lib eating, and have observed health benefits starting in as little as 2 weeks, in insulin resistance, asthma, seasonal allergies, infectious diseases of viral, bacterial, and fungal origin (viral URI, recurrent bacterial tonsillitis, chronic sinusitis, periodontal disease), autoimmune disorder (rheumatoid arthritis), osteoarthritis, symptoms due to CNS inflammatory lesions (Tourette’s, Meniere’s), cardiac arrhythmias (PVCs, atrial fibrillation), menopause-related hot flashes. We hypothesize that many other conditions would be delayed, prevented, or improved, including Alzheimer’s, Parkinson’s, multiple sclerosis, brain injury due to thrombotic stroke atherosclerosis, NIDDM [noninsulin-dependent diabetes mellitus], congestive heart failure.”

The method they mention is alternate-day fasting, but as we’ve seen, it matters less whether you do it every day, every other day, or as little as 3 days a week. You’ll still help protect yourself from all the bad things that can drain your retirement savings and ruin your golden years.

But what, exactly, is behind this “live longer, live better” effect? Dr. Mattson has one very specific, very powerful idea: Intermittent fasting improves your body’s ability to clean up after itself, on a cellular level.

Think about it: You’re not just a solid mass; you’re a collection of individual cells carrying out very specific functions—dividing, processing nutrients, creating energy. All of that activity creates waste, in the form of free radicals—the office clutter of the human metabolism. Project that over a lifetime, where the creation of clutter outpaces its cleanup, and suddenly you can’t remember the name of the guy who’s been tuning up your car for three decades. You sprint to catch the bus just like you used to, but now the bus always wins.

That’s aging in a nutshell: Cells have been working so hard for so long that they lose the ability to purge their waste and broken parts, and their function is compromised.

But not on the 8-Hour Diet.

When your cells are subjected to the minor stress of intermittent fasting, they can operate at peak efficiency. They do a better job of clearing out damaged cell structures and spent mitochondria, the equivalent of decommissioning the nuclear power plant before it destroys the groundwater. Less mess on the factory floor, better output from the machinery, longer operating life span for the factory, better product: you.

Scientists like Dr. Mattson have become convinced that intermittent fasting is an effective buffer against the major causes of death most of us have to worry about: heart disease, cancer, diabetes. Dodging or delaying those threats is in itself a profound life extender.

Says Dr. Mattson: “Dietary energy restriction can reduce tumor growth, it can protect neurons in models of neurodegenerative disorders, it can improve cardiovascular health—effects on blood pressure, for example—so being able to better understand how those changes are occurring may help us optimize those anti-aging effects.”

A definitive summation of Dr. Mattson’s research area appeared in
Ageing Research Reviews,
under the title “Caloric restriction and intermittent fasting: two potential diets for successful brain aging.”

OK, beach reading it isn’t.

But it just might be the kind of reading that could land you at the beach resort of your choosing, at age 87, still wheeling and dealing at the top of your game. For buried deep in Mattson’s report is this prime nugget of science speak: “Overall, from many experimental studies … [intermittent fasting] seem[s] to chronically reduce the circulating levels of insulin resulting in an eventual enhanced glucose mobilization and an enhanced insulin sensitivity, both of which serve to maintain a supply of glucose for the vital organs, central
nervous system, and gonads to support these critical organs in time of limited energy intake.”

I’ll spare you the chore of pasting that into Google Translate.

Dr. Mattson is saying that intermittent fasting (IF) torches your body’s energy supplies (so bye-bye belly fat) and makes sure that every last bit of insulin is accounted for in your cells, so that your vital organs (heart, brain), central nervous system (everything attached to your brain) and gonads (yes, well…) are being fueled properly. Basically, your body just doesn’t feel like it has the luxury of becoming fat and diabetic.

So what does that have to do with your mental acuity? And why does it mean holding onto all your faculties—and making them even sharper—as you age?

Do you know what your body’s number-one energy hog is? It’s not your muscles, your hard-pumping heart, or even your ever-rumbling belly. It’s your brain. After all, if there isn’t enough coffee in the control tower, the whole airport shuts down. Likewise, if your bodily control tower runs into a chronic energy shortage, it just might forget to send out the signal to do important stuff like go to work, pay the mortgage, or breathe. So when your body experiences a void between meals, it burns the fat stores in your front porch to keep the lights on upstairs. But on the 8-Hour Diet, it’s not just your body that’s changing.

Taking time between meals puts your brain to the test, as well. Go back to Dr. Mattson’s analogy of intermittent fasting as exercise for the brain. When you exercise, your muscles build new cells to better accommodate the challenges they’re being asked to meet. Your brain does the same thing. It meets the challenge posed by energy restriction by increasing the number of cells and synapses available for
processing information. Think again of the brain as the control tower of your own personal airport. When there’s the threat of a strike by air-traffic controllers, you hire more of them to fill the need to land all those planes safely. The 8-Hour Diet makes sure there are plenty of fresh recruits to handle the mental workload.

The result of all that brain exercise? The snappiest synapses this side of Stephen Hawking. If there was a Tour de Smarts, you’d be tested for steroids. Just look at how you’ll benefit: