Low-calorie meals can look tasty too. (Photo by yomi955)
The press just don't seem to get enough of caloric restriction these days. The latest article on the subject of living longer through being hungry appeared last week in Houston Press.
Of course technically, the goal of caloric restriction is not being hungry per se but rather living longer. Some practitioners do report not feeling hungry, even though their calorie intake is much lower than average. Apparently the distinction between staying hungry and eating less is not so important to these scientists.
Semi-starvation doesn't sound like a party, but calorie restriction — a scientific term meaning undernutrition without malnutrition — is now being touted as the latest fountain-of-youth secret for extending the human "health span" and possibly the life span. Gerontologists, oncologists, biochemists and biologists like Bauer, engaged in calorie restriction studies on lab animals, believe they've found an effective way to stave off cancers, heart disease, diabetes, arthritis, Alzheimer's and many other ailments. Staying hungry and living lean, say some researchers, is the only mechanism scientifically known to slow down the aging process and prevent age-related illnesses.
The interesting part of the article are the interviews with members of the Caloric Restriction Society, a community of people devoted to living la vida low-cal. One of them, Shannon Vyff, is on a pretty strict CR diet, and based on her meal times, also on a condensed-window version of intermittent fasting:
Vyff now eats once a day, usually a lean chicken breast poached in water, some steamed broccoli or squash and maybe a glass of fresh orange juice. She eats red meat once every two weeks and prefers it cooked rare. Her daily calorie count hovers around 1,200 if she's not exercising and 1,600 to 1,800 if she runs five or ten miles on the treadmill. She's also on a local roller derby team. When she's in training for that, she might help herself to a few extra morsels. Her favorite treat: six raw walnut halves and three Ghirardelli chocolate chips.
On a side note, like myself, she also posts at the Immortality Institute forums, a worthwhile place to visit if you're looking for up-to-date information and discussion on matters related to life extension. If I have questions about specific supplements, this is the place I'll ask first.
What I found most strange in the article was the comment by Jonathan Bauer, a scientist working at a center for ageing center. He's correct in saying that there's no proof of caloric restriction working on humans (because the scientists making such an experiment would die before the participants), but where he comes up with his "best guess" is unclear:
The best guess in the scientific community is that starting a program of calorie restriction in your thirties might add two years, says Bauer. "If you start in your forties, it's six months. Start later than that, it's negligible. It could be a few extra weeks."
First, based on the animal data, the effect of CR depends on how strict the diet is; i.e. the less the animals eat, the longer they live (up to a point, of course). So where exactly does this two year number come from? Does it refer to people on a 10%, 20% or 40% caloric restriction diet?
Second, it's not clear whether Bauer is talking about maximum lifespan or mean lifespan here, but since we already know that people who eat healthy can live more than a decade longer than people on unhealthy diets (due to less cancer, less cardiovascular disease, less diabetes), two years seems much too conservative an estimate. Not to mention the ridiculous claim of a few extra weeks.
The key question when discussing lifespan (and a lot of other things, for that matter) should always be: "Compared to what?" Perhaps Bauer means that when you compare a non-CR'd person eating a healthy diet to a CR'd person, the difference in lifespan is only a few years. There he may be correct, but I would like to see just where he got this number from, since as he himself says, we don't know how CR affects longevity in humans.
In addition to caloric restriction, the article also discusses resveratrol and raw food diets. Nothing new here, but getting the word out on resveratrol is still good. Most people still don't know what resveratrol is, so at this point, it's all good publicity. The raw food part is mostly about losing weight rather than extending lifespan.
There's also a very special bonus at the end of the article, so be sure to read the whole thing. Hint: it's a joke about caloric restriction that every writer just has to mention to appear witty. I wonder if putting that joke on a CR diet would make it seem less old.
For more information on anti-aging and calorie restriction, see these posts:
Caloric Restriction Improves Memory in the Elderly
Anti-Aging in the Media: National Post on Caloric Restriction
Anti-Aging in the Media: 60 Minutes on Resveratrol
Anti-Aging in the Media: Newsweek on the Search for Longer Life