The idea that eating less can prolong life has been gaining traction in recent years, thanks to studies on many organisms that correlate fewer calories with longer life.
A group called the Calorie Restriction Society has formed to encourage and assist people in reducing their long-term caloric intake for the sake of health. Their diet, called Calorie Restriction with Optimal Nutrition (CRON), is intended to drastically reduce caloric intake without starving the body.
We're talking about more than skipping dessert. The CRON diet aims for a weight of 10–25 percent less than what you weighed in college (assuming you were healthy, not anorexic or obese). I'm 6 foot 2 and weighed 160 pounds when I was 20. So if I were a CRONie, as they call themselves, I'd aim to weigh about 130 pounds—or 55 pounds less than my current weight.
That may sound extreme, but CRONies recently found validation in the results of a long-term study on rhesus monkeys.
The monkeys were divided into two groups, one of which was fed 30 percent fewer calories than the other. The researchers, led by Ricki J. Colman and Richard Weindruch at the University of Wisconsin, reported in Science magazine's July 9 issue that after 20 years, the dieting monkeys show significantly less diabetes, cancer and heart and brain disease than the control group.
Calorie restriction entered the mainstream in the 1980s, when UCLA researcher Dr. Roy Walford began publishing books, including The 120-Year Diet, based on his research with mice. Walford died at 79 of Lou Gehrig's disease, and his daughter Lisa Walford now carries the torch. A prominent CRONie, she's 5 feet tall, weighs 80 pounds, and according to her recent book, The Longevity Diet, enjoys a daily breakfast of four walnuts, six almonds and 10 peanuts, which is eerily similar to but somewhat less than what I fed a five-ounce parakeet I recently babysat.
Another of Walford's disciples was Richard Weindruch, co-author of the recent monkey study. Weindruch also co-founded LifeGen Technologies LLC, a company that "works with drug makers to quantify the effect of possible life-extending drugs." LifeGen's business plan, based on the premise that most people don't have the willpower to limit their caloric intake by 30 percent, is to identify and replicate in pill form the biochemical processes triggered by caloric restriction.
When I reached Weindruch by e-mail, he admitted that he himself doesn't follow a calorie-restricted diet, though he does eat "lots of vegetables and not much meat," despite his team's conclusion that their data "demonstrate that caloric restriction slows aging in a primate species."
While the CRONies are fasting for joy at this conclusion, many scientists and health experts don't buy it.
Most of the monkeys are still alive, and are expected to live many more years, so it's too early to know if the dieting monkeys really will live longer. And at this point, according to the researchers, the difference between the two groups in terms of the deaths that have occurred so far is not statistically significant.
If there isn't a significant difference in mortality between the two groups, why has this study made headlines around the world?
The researchers excluded monkey deaths deemed not due to age—such as deaths occurring under anesthesia while blood samples were taken—which allowed them to show a statistically significant difference between the two groups. But skeptics argue the low-cal diet could have made the monkeys more susceptible to health threats not usually associated with age.
There's also reason to believe that laboratory conditions don't adequately simulate real life. Studies that show mice to live as much as 40 percent longer on a calorie restriction diet are done with lab mice, which have been bred for high fertility and other characteristics. But other research shows that mice derived from wild populations don't live longer under calorie restriction.
Given that the average American consumes more than 3,700 calories per day, and that much of it comes from junk food, some calorie restriction would probably be a good thing for many of us. But if you're not fat, does it make sense to starve yourself from thin to bony?
I wonder about the origin of the monkey chow. The materials and methods section of the study doesn't identify the monkey diet, specifying only that "animals in this study are fed a semipurified, nutritionally fortified, low fat diet containing 15 percent protein and 10 percent fat."
Not all calories, protein and fat are equal. Meat from grass-fed beef, for example, has a healthier balance of omega-3 and omega-6 fatty acids. Protein from soy has been linked to intestinal problems in kids and thyroid illness in adults. Trans fat increases the risk of heart disease. If the monkeys were fed a diet from McDonald's, for example, a 30 percent reduction in calories would certainly explain the relative lack of diabetes and heart disease.
So while the monkey study results are interesting, I'm sticking with my filling diet of naturally produced and minimally processed foods. And if I'm wrong? Well, if living 120 years means 120 years of semi-starvation, I'm not sure I see the point. I don't think I'd feel too good, or look too pretty, at 130 pounds.
Ask Ari: Cookware concern
Q:Despite the fact that a link between aluminum cookware and Alzheimer's disease has been disproven, I still prefer to avoid using aluminum pots. However, all the stainless steel cookware that I've seen has aluminum in the base.
So, is it better to use enameled cookware, stainless steel or stainless steel only if the aluminum is sandwiched in steel so it's not in contact with the food?
A:The link between aluminum and Alzheimer's, which was based on the discovery of trace aluminum in the brains of Alzheimer's victims, has been disproven. But aluminum can harm the kidneys, and has been shown to leech phosphorus and calcium from the body, which is bad for bones, so you're right to want to avoid it.
This is difficult, however, because aluminum is everywhere. It's the most abundant mineral in the earth's crust and it's ubiquitous in plants, soil and water. It's also commonly used in antiperspirant, antacids and, as you noted, cookware, where aluminum is only a threat when acidic ingredients like wine, vinegar, tomatoes and other fruits are cooked in it. The acid causes the aluminum to leech into the food.
I avoid aluminum cookware, as well as pots made from anodized aluminum, in which the aluminum surface is electrochemically treated with a coating of aluminum oxide, which doesn't react with acid. I avoid anodized aluminum cookware because the coating can get scratched, opening the door to aluminum exposure.
Aluminum is popular in cookware because it conducts heat evenly and quickly. Stainless steel is a poor heat conductor, so aluminum is often used as the core of the base and sides of stainless steel cookware. The aluminum-core variety is sufficiently contained that it shouldn't be a problem. But if you really want to avoid aluminum, get copper-core stainless steel.
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