Take food labels with a pinch of salt

At a time of global poverty and famine, there is a tragi-comic irony at the spectacle of Western grown-ups having to be taught to eat less. But appetite and abundance have rendered us ignorant.

At the Pritikin Longevity Centre in Florida, building mental as well as bodily muscle is the mission. To this end, once a week, Pritikin ushers its clients through a local restaurant to show them how to healthily negotiate a calorie-dense, salt-rich menu.

The rules are: start meals with a salad (bring your own dressing); ask about preparation methods and request no added oils, butter, cream, salt or sugar; divide a main course dish between two and add two vegetable side dishes; talk to the manager and let him or her know your needs.

(In my own London dining experience at Giraffe, a breakfast place in Hampstead where for the last eight years I have met twice a week with two other health-conscious mates, using our total yearly spending there as a bargaining chip, we lobbied successfully to have steel-cut oatmeal put on the otherwise calorie dense menu.)

Pritikin also marches interested clients through a local whole food supermarket to teach them both how to read food labels and how to choose the healthiest option. (In Britain, the labelling is even smaller and more confounding.)

Pritikin admonishes its clients never to believe the front of any package, covered as they are with weasel words such as 'enriched', 'all natural', 'fat-free, 'baked' and 'seven-grain'. The key is knowing how to decode the nutritional facts on the label of contents. This is a quick calculation: the proportion of fat should never be more than 20g per 100g; the sodium should be 0.1g per 100g; check to see if sugar, or derivatives like corn syrup and fructose, are among the first three to five ingredients; if so, avoid the product.

On my whirlwind trip through the store, the nutritionist Gayl Canfield plucked off the shelf a can of Pam, the spray-on 'fat-free' cooking oil. The 'fat-free' serving, it turned out - according to the label - was a one-third-of-a-second spray. Anything more was hugely high in calories.

At the fat-free dairy, Canfield took out a fruit-flavoured yogurt and looked at the label. "Excuse me, 'fat-free?'," she said, pointing out the elevated calories in the fruity yoghurt. "When they add fruit, they add tons of sugar, which multiplies your calories. Add your own fruit to natural yoghurt."

The eternal vigilance at Pritikin about food is also applied to exercise, which is crucial to the reduction of hunger. "Research shows that most of the people who burn up 500 calories in exercise, don't eat more calories than they burn off," resident nutritionist Jay Kenny said.

Although any exercise is good, for the maximum weight loss and health benefits Pritikin preaches an exercise gospel of 45-90 minutes six times a week.

By 10am at Pritikin, the exercise regime is over; by then, having risen for breakfast in the moonlight at 6.30, the clients have stretched, run for three-quarters of an hour in the gym, and been dispatched to lift weights, work their core, develop their flexibility and manage their stress in yoga, or, if they wish, get an extra aerobic workout in the amoeba shaped pool.

The rest of the day is given over to a combination of educational lectures, voluntary exercise (spinning classes, salsa dancing among them), and whatever leisure pursuits capture the imagination. (Some play tennis on the nearby courts; others prefer shopping at the local mall; some sit around until Happy Hour schmoozing in the mahogany-lined main room.)

Many of the guests are returning clients who enjoy the rigour of the Pritikin lifestyle or recidivists who merely want to lose a few pounds so they can go back to their old bad habits; some, like Anne Sanan of Tampa, Florida, who was accompanying her unwell husband for three weeks, most definitely did not get the Pritikin religion.

"I hate it," she said. "They should be billing this as a medical facility, not a spa. I'm going to the jeweller's. My husband is buying me a bauble to make up for this. We're talking major carats." She added that her husband, who at the age of 60 has three stents in his heart, had modified his lifestyle, liked the place, and would be returning.

Although Pritikin will be leaving its current well-worn residence at the Turnberry Isle Club in 2010 and is currently exploring plans to expand into a sort of beach front residential hotel, the point of the place is not about luxury but about results. And the numbers are incontrovertible. In my case, when I stepped back on the scales after 10 days of moderately hard work, I'd burned off nearly 27,000 calories, had lost 8lb, and my girth had shrunk from 43 to 40 inches.

Even better, all my life-signs were dramatically improved: triglycerides down from an elevated 162 to a healthy 95; cholesterol total from 162 to 95; blood pressure from 141/82 to 112/68.

The prize of nutritional and medical knowledge was definitely worth the struggle; the deeper value to me, however, was existential. I felt easier in myself. The cloud of morbidity that hovers over old age had been somehow lifted; calm resolve seemed to have taken the place of resignation. Death would inevitably have its day. Meanwhile, by taking charge of my health, I was honouring the blessing of what remained of life.

PREVIOUSLY IN THIS SERIES:DAY 1: MY TICKET TO LONGEVITYDAY 2: HOW I LEARNED TO THINK THINInformation: www.pritikin.com  ·