In the battle to be crowned the most popular diet of 2014, should it be paleo or alkaline diet that gets your vote? Pete Bee investigates

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They are head to head in the battle to be the most popular diet of 2014. Compare the paleo and alkaline diets and there are similarities. Both eschew modern, processed foods along with many cereals and grains. Each claims to be based on the eating habits of our ancestors. Beyond that, the principles differ wildly. So how do the pros and cons for each stack up? Here we present the evidence to help you decide which, if any, is for you:

In a nutshell

PD: Eating as our hunter-gatherer ancestors did with a focus on lean meats, seafood, eggs, nuts and seeds, fruit and vegetables. If cavemen didn’t eat it, neither should you. "By following these nutritional guidelines, we put our diet more in line with the evolutionary pressures that shaped our current genetics, which in turn positively influences health and well being," says Loren Cordain, professor of health and exercise science at Colorado State University and author of The Paleo Diet. It doesn’t always translate easily to the weekly supermarket shop - grass-fed and organic foods are recommended to limit exposure to pesticides, antibiotics, and other chemicals that didn't exist in Stone Age times.

AD: You eat to optimise your body’s PH balance. Our blood is slightly alkaline, with a normal pH level of between 7.35 and 7.45 and the theory is that our diet should reflect this pH level. That means consuming somewhere in the region of 70% alkaline foods and 30% acidic. Plenty of the right kind of vegetables, nuts and seeds. Non-sugary fruits and healthy fats are on the cards. However, it’s not as straightforward as it sounds. Foods you might think of as acidic often aren’t - like lemons and apple cider vinegar. And cooking plays a role: raw spinach is alkaline, cooked is acidic. Monitoring your PH is a downside: it involves testing your urine.

So what’s off the menu?

PD: The list is lengthy but not overwhelming. Dairy, cereal grains, other grains including quinoa and buckwheat, processed foods, legumes, starches, sugar, processed foods, sauces, vegetable oils, salty foods. And if it comes in a package, don’t touch it with a bargepole.

AD: At first glance, this looks less daunting. Meat, seafoods, dairy, most grains, processed foods, starches, sugar, vegetable oils, fermented foods, dried fruits are to be avoided. But the more you look into the diet, the more complicated it gets. Some foods change from acid to alkaline (or vice versa) when they are metabolised by the body. Legumes and beans, blueberries, plums, currents and cranberries are all off limits as are corn, olives and butternut squash.

How much can you expect to lose?

PD: According to author Loren Cordain, the paleo approach “works with your genetics” to boost your health and potentially trigger a weight loss of “up to 75 pounds [over 5 stones] in 6 months”. However, the book stresses that weight loss depends on regular exercise, good sleep patterns and not gorging on too many carbs or calories.

AD: Again, there are no robust clinical studies looking at its weight-loss potential, but the ban on processed food and emphasis on eating whole grains, vegetables and soy products will likely yield fat loss. Anecdotally, there are claims that the diet can shed fat rapidly. “The first benefits tend to be weight loss, increased vitality and improved complexion,” writes Dr Stephen Domenig, author of The Alkaline Cure, a 14-day plan. Vicki Edgson , nutritionist and co-author of Victoria Beckham’s bible, Honestly Healthy, says the approach is not a weight loss plan, rather, a way of eating, although losing weight and banishing bloating is often a welcome result.

Celebrity Credibility

PD: For a long time, it was a secret among the CrossFit brigade and athletes. But the diet’s popularity sky-rocketed when celebrities got wind of it. Megan Fox and Matthew McConaughey and Miley Cyrus are among those who are fans of the Caveman approach. Jessica Beal says, “It just leans you down and slims you up and takes that little layer of fat, skin, and water-weight right off your body”.

AD: This diet streaked ahead in the celebrity stakes when Victoria Beckham, the queen of lean, tweeted about how much she loves the alkaline bible, Honestly Healthy which promotes the approach. Kirsten Dunst, Jennifer Anniston, Uma Thurman and Gwyneth Paltrow are also followers. And the supermodel Miranda Kerr has said: “I eat low-GI, high-alkaline foods, drink filtered water and eat mostly fresh produce and very little meat.”

Any evidence that it works?

PD: In its defence, Cordain is based at Colorado State Univeristy and is one of the world’s leading researchers in the area of evolutionary medicine. But beyond his obvious pedigree, scientific backing that the diet works is scant. But when it comes to weighing up the benefits of the diet itself, evidence is scant. One small study published in the journal Diabetologia did report that the approach improved blood sugar over 12 weeks compared to a Mediterranean diet that allowed grains, low-fat dairy, and oils, but a larger study would be needed to confirm any benefits. Given the lack of evidence, many experts remain opposed to it. Last year a report by the influential US News & World Report analysed safety, nutrition, weight loss and the effects on diabetes and heart disease of 28 diets. And paleo was placed in joint last place (with the Dukan Diet), with the judges saying they “took issue with the diet on every measure”.

AD: Since our bodies are inherently designed to maintain their own pH balance, many nutrition scientists claim a dietary approach to redress the balance is unnecessary - and, anyway, doesn’t work. To be fair, there isn’t a lot of evidence that trying to achieve pH neutrality through food is helpful. A 2012 report, published in the Journal of Environmental and Public Health, reviewed the published studies and drew mixed conclusions. On the positive side, the diet is full of fruit and vegetables, a benefit in itself. One study a few years ago suggested that eating more foods metabolised into alkaline residues (mostly fruit and veg) and fewer acidic foods (protein and refined grains) reduced the loss of muscle mass in a group of older subjects. An alkaline diet can help reduce the likelihood of kidney stones. Beyond that, there is little to support the notion it boosts health.