This study looked at CRONies Calorie Restriction Optimal Nutrition Society members who restrict calories by 25% and also looked at CR rodents. The rodents are able to extend life span by 25 to 50 percent. The CRONies expect to live past 100.
The investigators compared core body temperatures of 24 people in their mid 50s who had practiced calorie restriction for at least six years to 24 others of the same age who ate a standard Western diet with higher calorie and fat intake. The researchers also measured core body temperatures in 24 endurance runners of the same age to determine if being lean — like both the calorie restriction group and the runners — was linked to lower body temperature or whether calorie restriction itself was necessary.
The people doing calorie restriction had a lower average core body temperature by about 0.2 degrees Celsius, which sounds like a modest reduction but is statistically significant and similar to the reduction we have observed in long-lived, calorie-restricted mice,” says principal investigator Luigi Fontana, MD, PhD. “What is interesting about that is endurance athletes, who are the same age and are equally lean, don’t have similar reductions in body temperature.
Organisms from yeast to rodents to humans all benefit from cutting calories. In simple organisms, restricting calories can double or even triple lifespan. It’s not yet clear just how much longer calorie restriction might help humans live, but those who practice the strict diet hope to survive past 100.
Dr K has said that endurance runners generally have a shorter lifespan than the norm. It is interesting that the endurance runners studied had higer core body temperatures than the CROMies did. Higher body temp leads to shorter telomeres and shorter lifespans?
Dr K has also said to assist in losing weight rapidly, drink lots of ice cold water. Is there a link to drinking ice water and length of telomeres? In NY there is the Polar Bear Club that relish in taking a swim out on Long Island in December. Do these crazys know something about longevity?
Will you reduce the calories you take in today in exchange for living a long and healthy life free of illness and nursing homes?
The consensus from this related previous thread is that intermittent fasting gives you the metabolic benefits of CR without the side effects of apathy and low libido pointed out by LadyAdmin.
Also, from my answer in this thread, cutting carbs alone without restricting total calories may have similar benefits.
Drinking or swimming in ice water will only lower your core temperature temporarily (if at all), and will increase caloric expenditure, not decrease it.
it does but it does not work in humans so far.....and it also has been a failure in primates. The pathway in humans seems to be stimulated is resveratrol but Glaxo bought Sirtus a few years back and ran some trials with their trans Resveratrol and they flopped in humans. SO the jury is out.......and the reason why temp drops is because the thyroid axis is down regulated in CR because of calorie restriction.......all dictated by leptin function. So overall its a poor strategy for humans.
The anecdotal evidence I've heard on hardcore CR practitioners is that they tend to lose their libido and general interest in things they once held dear. So if that's what CR does to you, I would gladly trade a few years.
I've been eating low calorie for 6 years now. I eat about 1200/1300 calories per day as a 5'2" woman. I'm not sure if that qualifies me as officially CR.
I don't do it for a longer lifespan. I do it because I have a damaged metabolism and that is what I need to do to lose weight and maintain that loss. I went up to 1500 calories for 6 weeks and gained weight.
For fun I put my food intake into one of the online logs today... I was over 4000 cals and I hadn't even gotten to dinner yet. Dinner wound up being two huge plates of indian food, probably at least 800-1000 cals but hard to quantify.
I'm 6' 145 lbs btw. I'd rather focus on quality of life and being hungry certainly interferes with my mental state.
Between some occasional IF, compressed protein feeding window (to induce autophagy as commented on by Mat Lalonde), and fasted workouts a la Art Devanny, it seems like we can get the best of both worlds, eating all the good paleo food we want.
Here's how you can practice calorie restriction but not feel hungry:
Go ketogenic. Do very low carb. I don't know why this isn't clear. If you stay away from carbs, whether starches or sugar, you will not feel hungry since you'll be in control of your insulin. When your insulin goes up to manage your BG, you'll feel hungry as insulin falls. Keeping insulin low will induce satiety.
Also, if you're serious about CR, stay away from butter, olive oil, even coconut oil. These pack a ton of calories and you're better off eating solid foods.
Of course, that's assuming CR is valid. I'm not so sure if it is. And I don't think all calories are equal. That is, calories from EVOO or coconut oil wouldn't count as much as calories from proteins. That's just my hunch, but who's to argue since mice live longer?
I bet if the study was actually performed to see which macronutrient calories count the most, CR might mean something. My suspicion is protein consumption is much more stressful than fat or carb consumption. Also, ketogenic diets may put some unneeded stress on the body.
However, insofar as sticking to a CR diet, nothing is better than Carb Restriction.
There are strong connections among fasting, calorie restriction, and ketogenic diets. In fact, they probably share mechanisms. THE NEUROPROTECTIVE PROPERTIES OF CALORIE RESTRICTION, THE KETOGENIC DIET, AND KETONE BODIES says
An expanding body of evidence indicates that ketone bodies are indeed neuroprotective and that the underlying mechanisms are similar to those associated with calorie restriction - specifically at the mitochondrial level.
I feel that a ketogenic diet (and/or intermittent fasting, as Ed advocates) is a better alternative, since it doesn't necessitate malnutrition, and associated problems, nor is it unpleasant.
I'll say what I said on the "Navy SEALs eat high carb diets" thread: You have to optimize what's important to you on the three orthogonal axes - health, performance, and longevity (credit Robb Wolf)
CR may make you live longer, but I don't want to be hungry that long!
As so often, I feel we can speculate, but this is biology, even the best speculation has only a small chance to be right, (Dr K's confidence for example always amazes me.)
We can all place our bets (have to really) but we just lack the knowledge.
...Perhaps there is someone here who knows someone who might be persuaded to actually do the experiment: compare CRd mice with pair-fed, normal fed and overfed low protein low carb mice (on a nonindustrial diet without a lot of PUFA etc) and compare them on the various parameters of interest