Eat less

Breakfast for Dave Fisher is always a single egg white. Even that he eats reluctantly, but does so to avoid taking his daily vitamin and mineral supplements — six capsules in all — on an empty stomach. Lunch and dinner, too, are carefully monitored: with superhuman discipline Fisher sticks to an intake of 1,600 calories a day, well below the 2,550 that the British Nutrition Foundation recommends for men. But Fisher doesn’t want to lose weight. Even when he started eating this way, 16 years ago, he had no excess pounds to shed.

Rather, he’s a dedicated practitioner of the controversial food programme known as “calorie restriction” (CR). Followers of the CR diet insist that by cutting back on calories, sometimes by up to 40 per cent of recommended levels (about as low as you can go before risking muscle wastage), they can slow the ageing process, as if putting their bodies into biological slow-motion. Some practitioners of CR confidently expect to live to 130. After all, they claim, theirs is “the only scientifically proven life-extension method known to modern science”.

That science dates back to 1935 when Professor Clive McKay, of Cornell University biology department, discovered that rats on a restricted calorie intake appeared to age more slowly, and live up to 50 per cent longer, than counterparts left to eat as they pleased. The same phenomenon has been observed in many scientific trials since then in mice, worms and dogs, and others. Fisher, 48, who owns a recruitment agency, started to investigate CR in 1989, when he read about one of those trials.

At the National Institute of Ageing, in Baltimore, Dr Mark Mattson is conducting the first major study into the long-term effects of meal skipping in humans. However, there is no research yet to demonstrate that CR works in humans, and there is concern that people who drastically reduce calorific intake risk deficiencies in vital nutrients.

Fisher decided to make changes to his lifestyle anyway, first eliminating confectionery and wheat and scaling down portion sizes. “As a child I always thought that, far in the future, ageing would be cured,” he says. “But this is something I can do today. All the science shows that CR works.”

At 5ft 10in (1.78m), his weight dropped from around 11st to 9½st (70kg to 56kg). “I looked gaunt and bony,” he recalls, “and I was hungry. Although I was eating less, I was still eating poor foods.” CR is not just a case of less food. The mantra is “calorie restriction with optimum nutrition”: the idea being that because practitioners aren’t eating a lot, anything they do eat must be packed with vitamins and minerals in order to avoid deficiencies.

A typical lunch for Fisher might be strips of chicken breast, prawns, a packet of blueberries, raspberries or beans, and a couple of dates. It sounds a lot, but to stick to 600 calories, he’ll often eat just a bit of each packet and throw away the rest. Dinner: perhaps prawns with chilli, then watermelon. Pasta and potatoes (high energy, but apparently not so nutrient-packed) are out. As are beef, pork, lamb and dairy. And no alcohol. On this regime, his weight has risen to 10st 11lb. That puts his body mass index (the indicator of ideal weight for a given height) at 20.8, at the lower end of the recommended range (18.5-25).

“I’m never hungry. I feel full of energy. Sometimes if I smell doughnuts, I might fancy one. But I’d never eat one.”

CR can be expensive — Fisher spends £15 on lunch each day — and there are side-effects: CR dieters tend to get cold even in summer: “My body isn’t wasting calories making excess heat,” Fisher says. Still, as far as he is concerned, CR is working. Two years ago he went to Washington University to take part in a continuing study of CR in humans, and a fitness test placed him in the top 10 per cent of the population for cardiovascular health, despite the fact that his energy intake means he can’t do much exercise. Other tests — body fat, cholesterol — indicated a man two decades his junior.

The Washington University trials were set up in 2002 and involve about 30 participants. Dr Luigi Fontana, clinical investigator, says CR practitioners seem to be ageing more slowly than the rest of us. “Take systolic blood pressure,” he says. “Usually, that rises with age reliably, partly because the arteries are hardening. In my group, mean age is 55, and mean systolic blood pressure is 110: that’s at the level of a 20-year-old.

“Of course, I can’t tell you if my subjects will live to 130. So many uncontrollable factors affect length of life. I don’t have enough evidence to prove these people are ageing more slowly, but it looks like it.”

Yet despite this, Fontana doesn’t follow CR himself: “I eat a healthy diet, but I don’t want to become fanatical about counting calories. Nutrition is just as important: I try to eat foods that are high in nutrients and low in calories, such as fruit, and avoid high-calorie, low-nutrient foods such as white bread.”

The Washington study finds many of its subjects through the world’s biggest organisation for followers of CR: the Calorie Restriction Society, in California. The society was founded in the early 1990s by Brian Delaney, an academic, and Roy Walford, author of the CR follower’s bible The 120-Year Diet. Walford was Professor of Pathology at the UCLA School of Medicine, and CR’s best-known advocate. He followed the diet himself, but died last year of motor neurone disease, aged 79. At the CR Society website — www.calorierestriction.org — followers swap recipes and discuss the latest research.

“I’m surprised that more people don’t know about CR,” says Delaney, 42 (top left) who at 5ft 11in say he is “not scrawny” at 10st (BMI: 19.52).

“Part of the problem is that it’s often presented as an all-or-nothing choice. Sure, we have members who cut back to 1,100 calories and hope to live to 150. But the science suggests that if you restrict calories a bit, you’ll age a bit more slowly. You don’t have to do the extreme version.”

Still, Delaney, who says the society membership of around 1,600 is “overwhelmingly male”, concedes that no one is yet sure of just how, exactly, CR might work. “The truth is, we still aren’t sure how CR slows ageing in rodents,” says Dr Brian Merry, a reader in biosciences at Liverpool University. “In CR, cells seem to produce damaging free radicals at a reduced rate. But we aren’t lab mice: it will take decades of further research to discover whether CR slows ageing in humans.”

He does point, though, to key anecdotal evidence. The inhabitants of the Okinawa islet of Japan, for instance, are known for their low-calorie diet — lots of fish, soy, and wholegrain rice — that crucially, and unlike most naturally occurring low-energy diets, is packed with nutrients. They also have the highest proportion of centenarians documented in any population: more than 600 in around 1.3 million. But Dr Merry says that he won’t try CR: “The evidence isn ’t good enough, and there are too many downsides.”

Dr Derek Shrimpton, a retired consultant on nutrition to the government and independent advice body the Health Supplements Information Service, suggests CR practitioners “are on a knife edge”.

“Unless they balance their diet exactly, they are in danger of becoming deficient in vital amino acids, in vitamins C and D, in selenium and zinc. Unless your body gets enough energy, you’ll suffer muscle wastage and feel tired all the time. No one has yet done CR for a lifetime, so who knows whether it’s safe, or if it works? Even if it does, most people wouldn’t be satisfied with such a monastic existence.”

For those seeking a long and healthy life, Shrimpton offers traditional advice: “Get your weight at the lower end of the recommended levels and keep it. Eat a varied diet, with lots of fresh fruit and vegetables.”

But for Dave Fisher, this line doesn’t promise enough. “No one wants to die now. So why think you’ll feel different at 80? I want the extra years CR can offer. If I get to 110, then they may have tools that will fix ageing. A kind of rejuvenation procedure,” he says. “People may call me obsessive, but this is logical behaviour.”