Thursday, April 03, 2014
Caveman diet twice as effective as modern diets
The “caveman” diet popular with celebrities from Uma Thurman to Tom Jones has been given the seal of approval by Swedish experts who found that it was more effective than some modern diets.
Women who adopted a so-called Palaeolithic diet lost twice as much weight within six months as those who followed a modern programme based on official health guidelines.
They also saw a greater reduction in their waist circumference, although the difference between the two groups became smaller after two years of dieting.
The Palaeolithic diet involves eating plenty of berries, vegetables and lean meats such as chicken, but some types of food such as bread, rice, pasta and dairy products are banned.
Scientists said it could be preferable to other forms of diet, such as those which are low in carbohydrates but high in fat, because it strips out all unhealthy foods meaning there are unlikely to be negative side effects.
It is designed to simulate what our ancestors ate before the advent of farming, meaning followers can eat whatever they like except for certain types of food including grains, refined sugars and salt.
One previous experiment found that men who followed the Palaeolithic diet for just three weeks were less likely to suffer from heart attacks and strokes.
In the latest study, published in the European Journal of Clinical Nutrition, researchers divided 70 postmenopausal, heavily overweight women into two groups.
One was told to follow a Palaeolithic diet, and the other a Nordic diet based on whole-grain cereals, low-fat dairy products, fruit, pulses, fish and vegetable oils.
Dr Caroline Mellberg, who led the study along with colleagues at Umeå University and researchers at Cambridge University, said: “Since pasta and rice and such things were excluded, most [participants] ate pretty normal things like a chicken fillet, but they excluded pasta and added vegetables instead.”
Participants were asked to design their diet to get about 30 per cent of their total energy intake from protein but found it difficult to reach that level and compensated by eating extra carbohydrates and five to seven portions of fruit and vegetables each day, she added.
“They lost weight probably due to a low energy intake,” she said. “It is quite hard to eat enough fruit and vegetables to fill your energy needs. None of them complained about being hungry, so I guess the foods are quite filling. They ate a lot.”
After six months those on the Palaeolithic diet had lost an average of 6.2kg of fat and 11cm from their waistline, compared with 2.6kg and 5.8cm in the other group, and levels of harmful blood fat known as triglyceride were also lower.
By the end of the two-year study the difference between the groups had narrowed, but Dr Mellberg suggested there could be a simple explanation – people on the Palaeolithic diet grew tired of it.
“I think the participants weren’t compliant,” she said. "It is quite a hard diet [to follow] in the Western world. We eat a lot of foods like bread, pasta, cereals.
“They were quite satisfied too, after the first year. They had lost a lot of weight and many of the participants did not want to lose any more, so they started to eat more normal foods.”
Catherine Collins, chief dietitian at St George’s Hospital in London, added that the low protein intake could have slowed the rate at which participants’ bodies burned calories over time.
“As the metabolic rate declines, at some point that will stop you losing weight,” she explained.
Obesity paradox: being thinner can kill you, says cardiologist Carl Lavie
For many, it's a lifelong battle - a never-ending nightmare of quick-fix diets, exercise fads and obsessing over the bathroom scales.
But what if the fight against fat was making you sick? What if the excess kilos you've been desperately trying to shed were actually protecting you against premature death? Could you get off the weight-loss treadmill and lengthen your life?
This is the theory put forward in a contentious new book that is ruffling feathers in the health sector.
At a time when obesity and its associated burden of chronic diseases is a growing global problem, the book, to be released in Australia this week, suggests our obsession with thinness is courting disaster.
In The Obesity Paradox: When Thinner Means Sicker and Heavier Means Healthier, US cardiologist Carl Lavie says our modern culture has been duped into thinking excess body fat is bad.
He says the key to optimal health for millions of overweight and obese people may be staying the size they are. ''Fat has been demonised by our society, and our research shows fat is not always the devil,'' he told Fairfax Media from his home in Louisiana - the fattest state in the US. ''You can be heavy and amazingly healthy. Fitness is a lot more important than fatness.''
Lavie, who works at the John Ochsner Heart and Vascular Institute in New Orleans, said a growing body of evidence, including his own research over a decade, shows that while excess fat can lead to risk factors for chronic illness such as cardiovascular disease and type two diabetes, once these diseases develop heavier people have better outcomes.
''This is the obesity paradox,'' he says. ''Among the patients who have heart disease, the overweight and moderately obese are actually doing considerably better, sometimes 30 to 50 per cent lower mortality rates, than the lean people who have the same diseases.
''In no way am I promoting obesity, but for the people who have been losing the battle of the weight, if they can at least become fit, then they can have a very good prognosis and good overall health.''
Lavie says it is unclear how the paradox works, but it may be that heavier people might never have developed chronic disease without weight gain, whereas thinner people may be genetically likely to become sick and have a poorer prognosis.
But Associate Professor Tim Gill, principal research fellow at the University of Sydney University's Boden institute of obesity, nutrition and exercise and eating disorders, says he is suspicious of the theory, arguing that some overweight people might have better survival rates because thinness is often linked to smoking, and that fat reserves can be useful if the body is under stress such as when undergoing surgery or fighting cancer or immune system diseases.
''As a message to the whole community the idea of an obesity paradox is counterproductive, because it's saying that being overweight is good for you and don't do anything about it, when really this observation only applies to a small group of people at a particular point in their life,'' Gill says.
Lavie stresses that for the morbidly obese, losing weight is still the best option, but says fixating on numbers such as waist circumference or body mass index - a measure that divides a person's weight by the square of their height to determine obesity levels - gives a false impression of health.
Frances Lockie, a Sydney public servant who writes a ''fat acceptance'' blog, is 92 kilos and considered obese, according to her BMI.
She believes our cultural obsession with leanness and weight loss causes stigma. ''It gives people a licence to be rude and make offensive comments because it falls under the banner of being concerned for your health,'' she said. ''I work out, I eat healthily and I see my doctor regularly, but if I was to try and get into the 'healthy' weight range I'd need to lose about 20 to 30 kilos and I genuinely don't know how I'd do that without chopping off a leg.''
Posted by jonjayray at 12:25 AM