The diet dilemma

18 December 2011 - 04:11 By Claire Keeton

Cutting carbohydrates can cut kilos, say the experts. But how far should you go? By Claire Keeton

Eat more turkey, but less stuffing, drink and be merry this Christmas and you could end the season looking less like Santa Claus and more like his sleek reindeer.

To stay healthy and lean you need only control the carbohydrates you eat, particularly refined sugars and starches - and not count calories, according to an authoritative book: Why We Get Fat and What to Do About It by science writer Gary Taubes.

Advocating a low-carbohydrate diet and the benefits of fats are nothing new - it's a similar principle to the popular Atkins Diet - but Taubes goes further and is more controversial. He shoots down the hypothesis that calories count; that overeating and inactivity make us fat.

Carbohydrate, not calorie, restriction is the way to shed fat and nobody needs to feel hungry, he argues. He also says, surprisingly, that exercise has minimal impact on weight loss - though many other benefits.

The pillars of diet and nutrition that have been drilled into us since childhood are wrong, Taubes argues in his latest book and its more detailed predecessor: Good Calories, Bad Calories.

Fats (oils, butter) are good, they are not the enemy, Taubes claims. Low fat diets do not work - look at how the obesity epidemic worldwide has escalated under these guidelines for weight loss - and we need fats to suppress appetite, he writes.

If you follow his logic, it's better to choose double-fat rather than low-fat yoghurt, which is bulked up by carbohydrates.

Carbohydrates should not be the basis of the food pyramid nor fats severely restricted, Taubes says. Yet the latest nutritional guidelines, from the World Health Organisation to the US Food Pyramid, make carbohydrates the main food group and limit fat intake.

Acclaimed sports scientist Professor Tim Noakes, director of the Exercise Science and Sports Medicine Research Unit at the University of Cape Town, agrees with Taubes: "I have seen how easy it is to regulate body weight if you limit carbs," he says. "Exercise will not lead to weight loss if you eat a high-carb diet and are insulin resistant."

A major Women's Health Initiative trial involving about 20000 women in the early 1990s found that after eight years of eating 360 calories less a day, they lost an average of only 0.9kg each and their abdominal fat increased, according to Taubes.

Noakes now lives on protein, eggs, vegetables, dairy and nuts and limits the amount of fruit he eats, choosing low-carbohydrate fruits such as grapefruit and apples. He limits his carbohydrate intake to about 60g a day and recommends programmes such as the Dukan Diet. He says most of the carbohydrate-restricted diets are similar to the Atkins principles.

Noakes says he is running faster than he has in 20 years and is the lightest he has been in 20 years: "I have so much energy. Sugar does not give you go. It makes you sit down and get fat."

Top South African dietician Anne Till acknowledges that carbohydrate reduction accelerates weight loss: "Atkins knew in 1970 that lowering carbs would lower insulin production and promote fat oxidation (burning)."

But Till strongly disagrees with Taubes's polarised approach, saying: "You do not have to make a choice between carbs and fats. Make the best choices for each group."

Fruit and vegetables such as blueberries and spinach are high in vitamins and low in carbohydrates.

Till says a rigid model doesn't differentiate between types of carbohydrates, and even fruit is put into a bad category. Unsaturated fats do have an important place in a balanced diet, she says. Research has shown that both fat-free diets and a diet high in saturated fats promote insulin resistance.

Till also challenges the idea that calories don't count, saying there is not enough scientific evidence to prove this - and how much we pile on our plates does matter. She says people on a low-carbohydrate diet are partly successful because they reduce calories: "Whenever you cut out an entire food group, by default you are restricting calories." Studies have found that people under-report what they eat by up to 27%, she says.

Till also warns that cutting out carbohydrates is difficult to maintain in the long run, and the health risks of this are not well documented: "Studies have shown that weight and appetite rebound on diets. It is hard to be compliant, adherent and maintain the (right) attitude."

Colon cancer, osteoporosis and a risk of being deficient in micronutrients are among the risks of eliminating good carbohydrates such as fruit and whole-grain produce.

The common ground between Noakes and Till is clear when it comes to sugar: "Refined sugars and starches are terrible for weight, insulin and appetite control and dietary compliance and they fast-track disease," says Till, while Noakes brands sugar a killer.

During the festive season it's hard to avoid sugar with the abundance of mince pies, cookies and candies on offer, but then again, Christmas comes only once a year.