BBC - Future - The secret to a long and healthy life? Eat less. In a restaurant setting sometime in the not- too distant future, a man and a woman are on their first date. After the initial nerves subside, all is going well. The man is 3. 3, he says, has been single for most of those years, and, although he doesn’t mention it, knows he is looking to settle down and have a family. The woman replies that she is 5. He had no idea – she looked his age, or younger. This is a dream of Julie Mattison from the National Institute on Ageing (NIA) in the United States. She envisions a time when chronological age ticks by with every year, but biological age can be set to a different timer, where elderly doesn’t mean what it does now. It sounds far- fetched, but our society has already made great strides towards that goal, thanks to advances in medicine and improvements in healthy living. In 2. 01. 4, for instance, the United States Health Interview Survey reported that 1. ![]() Consume Less Live More![]() Three decades earlier that number was 2. In other words, as well as benefiting from longer lifespans, we are also experiencing longer “healthspans” – and the latter is proving to be even more malleable. To paraphrase and update a speech from John F Kennedy given at the first White House Conference on Ageing in 1. Healthspan is proving to be even more malleable than lifespan So, what do we need to do to enhance the length and quality of our lives even more? Researchers worldwide are pursuing various ideas, but for Mattison and colleagues, the answer is a simple change in diet. They believe that the key to a better old age may be to reduce the amount of food on our plates, via an approach called “calorie restriction”. This diet goes further than cutting back on fatty foods from time- to- time; it’s about making gradual and careful reductions in portion size permanently. Since the early 1. ![]() Across the animal kingdom, in other words, calorie restriction has proven the best remedy for the ravages of life. And it’s possible that humans have just as much to gain. The idea that what a person eats influences their health no doubt predates any historical accounts that remain today. But, as is often the case for any scientific discipline, the first detailed accounts come from Ancient Greece. Hippocrates, one of the first physicians to claim diseases were natural and not supernatural, observed that many ailments were associated with gluttony; obese Greeks tended to die younger than slim Greeks, that was clear and written down on papyrus. Spreading from this epicentre of science, these ideas were adopted and adapted over the centuries. And at the end of the 1. Century, Alvise Cornaro, an infirm aristocrat from a small village near Venice in Italy, turned the prevailing wisdom on its head, and on himself. If indulgence was harmful, would dietary asceticism be helpful? To find out, Cornaro, aged 4. He ate bread, panatela or broth, and eggs. For meat he chose veal, goat, beef, partridge, thrush, and any poultry that was available. Low-Calorie, Lower Fat Alternative Foods. These low-calorie alternatives provide new ideas for old favorites. When making a food choice, remember to consider vitamins. Permanently cutting the daily calories you consume may turn out to have a profound effect on your future life, according to some tantalising scientific studies. ![]() ![]() ![]() He bought fish caught from the local rivers. Restricted in amount but not variety, Cornaro claimed to have achieved “perfect health” up until his death more than 4. Although he changed his birthdate as he aged, claiming that he had reached his 9. Century, a time when 5. In 1. 59. 1, his grandson published his posthumous three- volume tome entitled “Discourses on the Sober Life,” pushing dietary restriction into the mainstream, and redefining ageing itself. With an additional boost of health into the evening of life, the elderly, in full possession of their mental capacities, would be able to put decades of amassed knowledge to good use, Carnaro claimed. With his diet, beauty became the aged, not the youthful. Longevity trials. Cornaro was an interesting man but his findings are not to be taken as fact by any branch of science. Even if he was true to his word and did not suffer ill health for nearly half a century, which seems unlikely, he was a case study of one – not representative of humans as a whole. But since a foundational study in 1. Of course, what works for a rat or any other laboratory organism might not work for a human. Long- term trials, following humans from early adulthood to death, are a rarity. Not only do we share 9. DNA with these primates, we age in the same way too. Slowly, after middle age (around 1. Rhesus monkeys) the back starts to hunch, the skin and muscles start to sag, and, where it still grows, hair goes from gingery brown to grey. The similarities go deeper. In these primates, the occurrence of cancer, diabetes, and heart disease increases in frequency and severity with age. Fed with specially made biscuits, the diets of the 7. University of Wisconsin and the 1. NIA are tailored to their age, weight, and natural appetite. All monkeys receive the full complement of nutrients and minerals that their bodies crave. It’s just that half of the monkeys, the calorie restricted (or CR) group, eat 3. They are far from malnourished or starving. Take Sherman, a 4. NIA. Mattison says that since being placed on the CR diet in 1. Sherman hasn’t shown any overt signs of hunger that are well characterised in his species. Sherman is the oldest Rhesus monkey ever recorded, nearly 2. As younger monkeys were developing diseases and dying, he seemed to be immune to ageing. Even into his 3. 0s he would have been considered an old monkey, but he didn’t look or act like one. The same is true, to varying extents, for the rest of his experimental troop at NIA. In 2. 00. 9, the University of Wisconsin trial published similarly spectacular results. Not only did their CR monkeys look remarkably younger – with more hair, less sag, and brown instead of grey – than monkeys that were fed a standard diet, they were healthier on the inside too, free from pathology. Cancers, such as the common intestinal adenocarcinoma, were reduced by over 5. The risk of heart disease was similarly halved. And while 1. 1 of the ad libitum (“at one’s pleasure,” in Latin) monkeys developed diabetes and five exhibited signs that they were pre- diabetic, the blood glucose regulation seemed healthy in all CR monkeys. For them, diabetes wasn’t a thing. In the ad libitum group, 3. In an update study from the University of Wisconsin in 2. The results show that ageing itself is a reasonable target for clinical intervention and medical treatment – Rozalyn Anderson “We have demonstrated that ageing can be manipulated in primates,” says Anderson. Whereas if you go after ageing you can offset the lot in one go.”Eating less certainly seemed to help the monkeys, but calorie restriction is much tougher for people out in the real world. For one, our access to regular, high- calorie meals is now easier than ever; with companies like Deliveroo and Uber. Eats, there is no longer a need to walk to the restaurant anymore. And two, gaining weight simply comes more naturally to some people.“There’s a huge genetic component to all of this and its much harder work for some people than it is for others to stay trim,” says Anderson. And then someone else walks past a table with a cake on it and they have to go up a pant size.”Ideally, the amount and types of food we eat should be tailored to who we are – our genetic predisposition to gaining weight, how we metabolise sugars, how we store fat, and other physiological fluxes that are beyond the scope of scientific instruction at the moment, and perhaps forever. But a predisposition to obesity can be used as a guide to life choices rather than an inevitability. If this wasn’t possible, she adds, she wouldn’t practise calorie restriction. Not only has Roberts seen the problems of obesity first- hand in her family, she knows the benefits of CR better than most. For over 1. 0 years she has been a leading scientist in the Comprehensive Assessment of Long- Term Effects of Reducing Intake of Energy trial, also known as Calerie. Over two years, 2. Both had health checks every six months. Unlike in the Rhesus monkey trials, tests over two years can’t determine whether CR reduces or delays age- related diseases. There simply isn’t enough time for their development. But the Calerie trials tested for the next best thing: the early biological signs of heart disease, cancer, and diabetes. Published in 2. 01. In the blood of calorie- restricted people, the ratio of “good” cholesterol to “bad” cholesterol had increased, molecules associated with tumour formation – called tumour necrosis factors (TNFs) – were reduced by around 2. Overall, the blood’s pressure was lower. Significant health benefits may be garnered in an already healthy body, but further trials are needed Admittedly, some benefits may come from weight- loss. Earlier trials from Calerie had included people that were obese as well as those with a healthy body mass index (BMI) of 2. Diseases and disorders previously thought to be age- associated diseases are now popping up in the obese population, she adds. But the latest results suggested that significant health benefits can be garnered in an already healthy body – a person who isn’t underweight or obese. That is, someone whose BMI lies between 1. Despite these results, evidence from further trials will be needed before someone with an already healthy BMI should be advised to reduce their calorie intake. With nearly 3. 0 years of data on lives and deaths, and blood and tissue samples, from nearly 2. NIA and the University of Wisconsin aim to shine a light into the black box of calorie restriction, illuminating just how it delays ageing. With less food, is the metabolism forced to be more efficient with what it has? Is there a common molecular switch regulating ageing that is turned on (or off) with fewer calories? Or is there an as of yet unknown mechanism underpinning our lives and deaths? The importance of monkeys like Sherman far outspans their lives. Calorie restriction may be one of the most promising avenues for improving health and how long it lasts in our lives Answers to such questions might be long in coming.
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