Stone-Age servings the Paleo diet: is eating like a caveman healthy or a fad?

The New Yorker once published a cartoon of two jutting-jawed, low-browed cavemen. One is complaining: ''Something's just not right - our air is clean, our water is pure, we all get plenty of exercise, everything we eat is organic and free range, and yet nobody lives past 30."

It's the image that springs to mind every time I hear of another celeb who has signed up for the Paleo diet. Welsh balladeer Tom Jones reportedly lost kilograms on the regime, and Miley Cyrus is another devotee (she of the enviably lithe figure).

The Paleo diet is named after the Palaeolithic era, the ''Old Stone Age", which started about 2.6 million years ago and finished in roughly 8000 BC, before arable farming began. The premise of the regime is that we go back to our ancestral diet and eat the foods that predate agriculture - namely, the fruit, veg and meat that hunter-gathering cave-persons would have eaten. This, advocates claim, is what we have evolved to eat, and what is best for us. Our modern diet, high in carbohydrates and processed food, is not what we are genetically programmed to consume and is, therefore, unhealthy. Really? Going back to the disconsolate caveman, life expectancy at birth in the late Stone Age was probably the mid-30s. These days life expectancy at birth is more than 80 in many countries, so why would we want to ape the lifestyle of our less enduring ancestors?

The point of the diet, maintains Joy Skipper, author of The Paleo Diet Made Easy , is that it cuts out refined and processed food, and carbohydrate-dense potatoes and grains. You can have root vegetables, which have plenty of carbs, but you can't have any dairy produce at all.

Pulses are also excluded - apparently they contain high levels of lectins that are toxic and inflammatory. So peas are out. Lentils, green beans, broad beans and baked beans: they're all has-beens to the Paleo dieter.

According to Skipper, the only thing that really does any good for health or weight loss is to change eating patterns for good. That sounds depressing - a lifetime without flour, sugar, alcohol, cheese and cream.

When I tried the Paleo diet I felt deprived and headachy, probably as a result of the lack of caffeine, but Skipper reckons if I stick to it, I will see great results.

I'm not sure I'm ready for the full-on lifestyle change. But a little Paleo in my life? I can see it makes sense. As long as I can still have tiramisu on my birthday.