Ordinarily, pizza makes us think of a half-assed meal or an indulgent snack (either, according to how much you've had to drink, or how much you'd rather it be one over the other), but what if it were an ideal fuel for runners? Runner and writer Matt Fitzgerald has made it so. Granted, without grease on your fingertips and yeast in your stomach, you might not want to call it "pizza." But we see no great loss here.
Enter: the greaseless, yeastless Greek Tortilla Pizza—the runner's option, with a Greek tortilla in place of dough, whole grains in place of white flour, one day's serving of veggies piled on top for nutritional value, and the whole thing ready for consumption in one sitting so you don't have to think about portion control. Best of all, says nutrition expert Georgie Fear: the Greek Tortilla Pizza can still be a last-minute decision (so long as you have the ingredients). Preparing it takes only 15 minutes, about the same time it takes to deliver.
Other strange physiological phenomena occur when the body is totally deprived of food, some that might be considered desirable, others not. The eyesight of one subject in a 1915 study improved dramatically on day 14 during a carefully monitored 31-day fast and was twice as acute at fast’s end as at the beginning. Others reported a peculiar lightness in their bearing. Heart rates can drop to 35 beats per minute. And there’s the nasty breath—breath that smells like a solvent such as acetone.
After abandoning their canoes, which had smashed among the waterfalls and rapids of a canyon, the 50-person Overland Party, led by Wilson Price Hunt, a young New Jersey businessman with no experience in the wilderness, split into two main groups in November, 1811. Trekking on foot, they followed the unknown river downstream toward what they hoped was the Pacific. Barren lava plains spread on both sides of the river gorge. With no game, and no fish appearing in their nets, they managed to trade with scattered bands of Shoshone Indians for a few dogs and horses. Consuming these—a group of 50 people trekking in winter could demolish the caloric equivalent of a large animal every few days, thus they traveled in two smaller groups—they chewed on bits of beaverskin and spare moccasins. Hunt stayed with the slower group, which included the family of the Indian interpreter, his pregnant wife, and their two toddler boys.
For a month, Hunt’s group struggled onward along the river. Then the river poured into a massive canyon—now known as Hell’s Canyon of the Snake River, the deepest canyon in North America. One snowy December day, as Hunt’s slow party struggled downstream over rocky outcrops, they spotted the other main party staggering back upstream on the opposite bank! This was the worst kind of news. Led by Scottish fur trader Ramsay Crooks, it had been stopped by the extreme depth and ruggedness of the canyon and the onset of winter’s deepening snows. Still worse, Crooks and his party verged on collapse from starvation and exhaustion due to the tremendous exertion and caloric needs.
Hunt had a small boat crafted from a horsehide and brought Crooks and a voyageur, Le Clerc, across the river from the starving party on the opposite bank. Crooks told him there was no way forward down the canyon on foot or boat. Hunt knew he now had to retreat upstream in hopes of finding Shoshone villages and food. They were at least ten days or two weeks away. Even after Hunt fed Crooks and Le Clerc the last of his horsemeat, however, they were still too weak to walk and became feebler with every moment. Hunt, loyal to a fault, trying to lead by consensus, wanted to stay with the dying men. Crooks was his friend and partner. But the 20 other members of his party, the voyageurs especially, harangued him to abandon Crooks and Le Clerc and retreat as hastily as possibly to the Shoshone villages and the hope of distant food.
“They said that we would all die from starvation,” wrote Hunt in his journal, “and urged me by all means to go on.”
The process had now begun for everyone.
The human body has a special mechanism to deal with starvation in these dangerous circumstances. A fascinating account on the physiology of human fasting can be found on the website derangedphysiology.com. Drawing on the classic 1970 study “Starvation in Man” by George F. Cahill, the website tells us that the human body, even when starving, wants to continue to feed nutrients to the brain, despite all else. The starving human body also tries to hold onto a certain reserve of ready energy for “fight or flight” or other emergencies.
Normally, the fuel driving our bodies is glucose (a simple sugar) and glycogen (glucose transformed and stored in the muscles). We constantly drain this fuel supply to power our muscle movements and metabolism. We refill this fuel supply through eating.
But under fasting conditions—starvation—the body makes a peculiar switch. The muscles and heart stop using up all the ready fuel—glucose and glycogen—saving some of it for emergencies, and start to draw on fuel made from the breakdown of the body’s fat reserves and what’s called “ketone metabolism.”
“The glycogen reserves in humans never get completely depleted,” according to the website. “There is at all times a hepatic [liver] reserve, waiting to mobilize and rescue the organism from some sort of horrible situation.”
But the brain has to function, too, in order to save the starving human from “some horrible situation.” The human body is remarkable among animals in that the human brain can function with alternative energy supplies to glucose. Some of the body’s fats are converted to what’s known as “ketone bodies,” which, only in humans, have the ability to enter the brain and power it. (The human brain of a 150-pound male requires about 325 calories a day, or the equivalent of about one-and-a-half energy bars, to keep the lights on.) Thus by switching over to alternative energy supplies like ketone bodies, the brain, too, helps save the body’s glucose reserves (as well as the body’s muscle mass) for emergency “fight or flight” situations like a kind of human rocket fuel.
The “acetone breath” of starvation or fasting comes from the metabolism of these ketone bodies into byproducts like acetone, which is then dissipated through urine and through exhalation from the lungs.
Eventually, however, as the fats are used up, the body will begin to break down its own proteins—its muscles and tissues—and convert them to fuel. (None of the physiology of starvation or fasting that I’ve read explains the deep voices such as Franklin’s, but I wonder if it has something to do with the proteins of the vocal cords breaking down. Maybe a reader will know the answer.)
“An organism which is consuming its own protein is truly struggling,” according to derangedphysiology.com. “That said, if your [human] organism is struggling it has some 6kg or so of protein to get through before it dies.”
Ramsay Crooks and the voyageur Le Clerc had clearly entered this protein-consuming phase of starvation, and had finally used up whatever rocket-fuel reserves they had possessed.
Hunt, deeply conflicted, profoundly troubled—were his loyalties to his good but dying men, or to his leadership of the group as a whole?—finally abandoned the starving pair in the canyon depths. But he didn’t forsake them entirely. He left them two beaverskins to chew on, and promised that as soon as he found food, he would send it back to feed them.
“Our paper basically revealed the truth and what we’ve been telling people forever,” declares Dr. Katz, who claims to have no “dog in the fight,” for one diet over any other. “Eating more fruits and vegetables is good for you.”
As for the reliability of the Austrian anti-vegetarian paper, “Your eyebrows go up,” says Dr. Katz. “The methodology doesn’t pass the sniff test.” For one, dietetically, very few Austrians eat fruits and vegetables. “So among the ones who say they do, who are they and why?”
In his experience, there are two groups who are vegans and vegetarians. “People who’ve eaten according to this diet their whole lives. And those who have cancer. So it’s their doctors who’ve advised them to go on this vegan or vegetarian diet.” But it wasn’t reported that way in this Austrian study. “So it’s just a very deeply flawed study.”
Besides, not all vegetarians are created equal. It’s easy to eat a vegetarian diet rich in fats and simple carbohydrates, which are terrible for you, says Dr. Aaron Baggish, associate director for the Cardiovascular Performance Program at Boston’s Massachusetts General Hospital. “And for athletes in particular, if they’re on a vegetarian diet, they tend to eat a lot of simple carbs.”
If, however, you’re consuming minimally processed foods and plenty of fruits and vegetables—whether you’re Paleo or vegan—you’re eating pretty healthily. “Eating wholesome foods is the cornerstone,” says Dr. Katz. “Especially for athletes.” (Complex carbs take longer to break down, and so continue to provide you with more energy.)
What most distresses Dr. Katz is the overattention placed on this or that diet, and not enough on applying what we do know. Constantly adjusting or changing one’s diet according to the latest breakthrough regimen (Lose weight! Run faster! Eat whatever you want!) is just missing the old-growth forest for the faddish trees.
“All we really need to do is commit to the fundamentals of what we know,” says Dr. Katz. “The theme of healthy eating is well-established, and the evidence is incredibly consistent—across years, across cultures, across everything.”
The study that garnered all the attention—a meta-analysis of 51 other studies—found that those with a Body Mass Index (BMI) of 18.5 or below had a 1.8 times higher risk of dying than people with a BMI in the normal range. Meanwhile, people classified as obese, with a BMI of 30-34.9, were 1.2 times as likely to die, while the severely obese—with a BMI of 35 or higher—were 1.3 times as likely to die.
What does that mean, exactly? Not what everyone seems to think it does. BMI is a simple formula, a calculation of height vs. weight that can be a useful indicator of health. But it’s not perfect. It can’t differentiate between muscle and fat, so two people might be the same height and weight—and thus the same BMI—but have a very different muscle to fat ratio, and different overall health. “Rather, a ‘robust body size’ is one where there is a good amount of muscle mass and a limited amount of abdominal fat,” Dr. Joel Ray of St. Michael’s Hospital in Toronto, who led the study, says. “BMI is not the best indicator of obesity-related mortality risk, but it is in underweight people.”
You also have to remember that being over- or underweight is not necessarily the thing that’s going to kill you. Low weight can be caused by factors like drug use, alcohol use, and poor self-care; a higher BMI can be accompanied by heart problems and diabetes.
But that doesn’t mean you should ignore BMI either. According to Dr. Steven Heymsfield, a professor at Pennington Biomedical Research Center at Louisiana State University, “BMI is only a first step in evaluating an individual’s health.” A high BMI is a good indicator that a patient needs other tests—for blood pressure, blood lipids and other risk factors.
If you want to be really careful, check both your BMI and and waist circumference. “That’s not a bad approach if you have the resources; the combined measure is a better index than either one alone in most studies,” Heymsfield says.
But no matter your BMI it’s a good idea to talk to your doctor about what that number actually means for you and to focus on what really counts: staying active.