Wednesday, November 21, 2012

Paleolithic Diet

First, let’s annoy the Creationists. Human beings evolved over time and we have been in our current form for about 200,000 years. We began in the Rift Valley in Kenya, spread north into Europe and east into Asia, then through to Australia (about 40,000 years ago) and north America (about 12,000 years ago). For most of that time we gathered and hunted for food. About 10,000 years ago we began to settle down and try agriculture as a means of growing our own food.

Let’s not get caught up in the actual dates, and focus on simple concepts. That is, trace your ancestors back far enough and they would be African. For most of human history we ate mainly animal foods, root vegetables, seeds, nuts, berries, fruits and eggs. Only fairly recently have we consumed dairy food, grains, alcohol, coffee and legumes.

The Pro side 
The argument for the Paleo Diet is that our digestive system has not evolved to handle the more recent foods we have added to the diet, such as grains and dairy. That is, we should be eating foods that were around through most of our evolution. As the diet comprises of minimally processed food and has a high protein content, it is quite filling, therefore it is unlikely that you will over-consume and start packing on the kilos/pounds.

A wide variety of nutrients are present if you include the full range of foods and, equally important, it is low in the components that we know can cause harm, such as excess salt, alcohol and saturated fat. All biscuits, cakes, pastries, confectionery, french fries and Krispy Kremes have gone, so the nutrient density will improve..

The Glycemic Index of the diet is low, probably a bit lower than regular healthy eating. When people move from standard fare to a Paleo diet their insulin sensitivity improves, blood pressure drops and body weight improves. To be frank, you could scoop up 100 people in any shopping mall, get them to cut out all treats, alcohol and takeaways and they too would all lose weight and feel better.

The Con side
There is accumulating evidence that the domestication of cattle, camels and goats provided a survival advantage when we started consuming their milk and, subsequently, yogurt and cheese. Domesticated animals became a guaranteed source of nutrient-rich food, with the earliest evidence being 7000 years ago in sub-Saharan Africa.

There is evidence that peoples in Europe were consuming grains 30,000 years ago, although it probably was gathered rather than cultivated.

With an emphasis on meat and seafood, the diet may be a bit more pricey than plain healthy eating, although you will save money once that nice bottle of red, your favourite chocolate and the gourmet ice cream has been deleted. It will be difficult to follow the diet to the letter because all meat was wild, so unless you shoot your own kangaroo, elk, moose, rabbit then you will be dining on domesticated animal flesh.

As far as we can tell Paleolithic man had an average lifespan of 35 years, with only 10-20% clocking up six decades. That doesn’t stack up well against the 80+ years we expect from non-smokers who eat their vegetables, walk the dog, give to charity, catch up with friends and laugh when they confuse the travel toothpaste tube for the tinea cream (which, believe me, doesn’t have a minty flavour).

Want to know more?
Should you follow a Paleo Diet? First note, that it will be tricky because you will be preparing virtually all your own meals, unless you are happy to relax the rules once a week or so. You can also do some reading of your own to determine your viewpoint. A free publishedreview article for those with a science background is a good place to start. It seems that humans turning to meat had a significant role in our evolution. If you prefer a more gentle read, then get hold of Loren Cordain’s book. He is a researcher from Colorado State University with a special interest in the Paleo Diet.

What does it all mean?
The argument for the Paleo Diet can be quite compelling, however we don’t know of a long-lived group of humans that have existed solely on the Paleo Diet. That’s not to say they wouldn’t live a long life. Naturally it won’t suit vegetarians, Meatless Mondayers, Mediterranean and Asian cultures with a lower reliance on animal flesh.

Of course, there is no single Paleolithic Diet. If we plonked you in the Tardis and set the dial for 10,000 years ago, your diet in north America, central Australia, France, and Viet Nam would all be different.

Anyway, it’s not for me. I enjoy a plant-based diet, which includes the tea leaf, the grape in the form of wine, and a little animal food because life is so much less without camembert. You, on the other hand, are your own boss.

Tuesday, October 23, 2012


Nuts did fall victim to the fat paranoia of the 1980s and1990s. Remember Nathan Pritikin and his diet? All nuts, except chestnuts were excluded if you wanted to follow his version of health. When his son Robert produced a “new” version of the Pritikin diet in 1990, nuts were permitted, with the exception of macadamias and coconut. But by then, the Pritikin Diet was forgotten. Pity, because Robert’s version was pretty sensible.

Nuts looking good
Now we are much more confident about our advice on food and fats, although the debate will continue for decades (eg at a conference recently it was claimed that there is no link between dairy fats and heart disease. Is that a double cream camembert I see?).

Certainly, we are pretty sure that nuts, particularly tree nuts and peanuts, are very good for your health. Yes, we are talking about unsalted nuts; and, you are right, peanuts are a legume and not a true nut, but I do include them because they have a very similar nutrient profile to tree nuts, like Brazil nuts and walnuts. Remember that there is no cholesterol in plant foods, therefore none in nuts.

Big study
There is now a good deal of research on nuts and there is mounting evidence that around 30g (1oz), about a small handful, each day could well be protecting you from conditions like heart disease and diabetes. One big European trial (Prevención con Dieta Mediterránea - PREDIMED) has tracked 7400 folk aged 60-80 years for five years as they followed either 1) low fat control diet; 2) Mediterranean diet with 50 mL olive oil daily; or 3) Mediterranean diet with 30g nuts daily.

The diet was controlled to some extent, making sure that soft drinks (sodas), cakes and sweets were limited. All three groups received educational sessions and were assessed for compliance.

Waist, brain & blood glucose all improve
Those who closely followed either Mediterranean diet had half the risk of type diabetes when compared to those on the low fat diet. They also had better cognitive function and a lower rate of brain decline. The better the adherence to the Mediterranean diet, the greater improvement in abdominal obesity ie there was less dangerous fat around the middle, especially in the nut lovers. Interestingly, their waist circumference was lower, even though their total weight may not have changed, suggesting a healthier distribution of body fat. And it is your waist circumference, not the number on the scales, that has the greatest effect on your health.

An important message
This study is just another nail in the coffin of the extremist low fat diets. We have reached a time when the concept of the Pritikin Diet, or the very low-fat diet, is no longer in favour for personal health. Fat in itself is not a problem. The fat found in nuts, avocados, seeds, good quality chocolate and oils does not cause a long-term health problem. As expected, it all comes back to the quality of your eating.

What does it all mean?
Eat unsalted nuts regularly. Forget the fat content. They won’t make you fat. Chances are that nuts will help install another barrier to health problems. I have nuts on my breakfast cereal (oats + 2 brand cereals who need to hand over some free product before I name them), with dried fruit (cranberries, yum) and skim milk. It is too early to give a league table of nuts, so the smart thing is to have a mix of your favourite nuts. Help your body and help nuts make a comeback by enjoying some everyday, or whenever you can.

PLOSone August 2012; 7 (8)  entire paper

Sage advice from the past

My favourite wellness thinker, Don Ardell, alerted me to a book with some dietary advice. Here is a quote:

"Another argument, and to my mind also a conclusive one, in favour of vegetarianism, is the true theory of population. If ever the earth becomes very densely inhabited with human beings, a great number of such animals as are raised for food can not possibly coexist. And as ten times the number of “rational creatures” can be sustained on the direct productions of the earth, that could subsist indirectly on the flesh of animals, the presumption is at least very strong at the races of domesticated animals will become extinct as the races of man progress."

As you have guessed, it wasn’t written recently. This is from the Hydropathic Cookbook published in 1854. (Click on the right hand arrow to scroll through the pages). His sentiment is proclaimed by many: less animal food, more plant food. The author RT Trall concludes his preface with the comment:

"I trust the time is not too far distant when the foundation for a better development of the human race will be established, in “teaching the young idea how to eat’” so as to secure uniform health, and realize the first and essential condition of universal happiness – “sound minds in healthy bodies.”

Well, we’ve been doing the teaching. It is not a young idea any more. The message is being transmitted but only a few have their tuners on the correct frequency. Maybe in another 150 years.

Trall RT, MD. Hydropathic Cookbook with Recipes for Cooking on Hygienic Principles  1854; Fowlers & Wells, New York

Monday, September 24, 2012

Eating habits - can they be changed?

Few Australians are good at maths

Smoking rates have dropped considerably over the last 40 years. That’s partly because, as smokers die, fewer smokers take their place, and partly because others have quit by changing a habit. Can we change another habit – eating better and eating less to lose weight? That, I think, is far too difficult for adults.

Democracy is not good for body weight
Why are we unlikely to see weight loss in the near future? Because we live in an affluent democracy where food is relatively cheap, available 24 hours a day, 365 days of the year and you have the freedom choose what you eat. The default position of humans is to take the short-term gains (taste, convenience) rather than look to the future.

This is why we have compulsory superannuation (in Australia). No-one can see, or wants to see, the future. When it arrives, they realise they have fewer than 10 years to save for retirement, or desperately search the internet for a “natural” cure for their ailment. We prefer the hope of a solution to the proven benefits of investment or prevention.

I’m not capable
One major barrier to educating the population is that 46% of adult Australians do not have the “minimum literary skills required for individuals to meet the complex demands of everyday life and work in the emerging knowledge-based economy.” (Adult Literacy and Life Skills Survey 2006). For numeracy skills, 53% of adult Australians do not meet the minimum level. Even of all those people who claimed they were good at maths, 44% did not meet the minimum numeracy skills! (Can you work out 10% of 120? Yes? Well done; only half of us can do that calculation.)

We love to roll out public weight loss campaigns with advertising suggesting that a paunch signals your downfall (cut to image of man wondering if he will live long enough to see his children graduate from high school) followed by a direction to a website, which means that half the population have already dropped out from seeking information. If you don’t have literacy skills then you are unlikely to be reading a well-meant on-linesolution.

I’m not even fat, anyway
Another barrier for weight loss campaigns is that as we getter fatter, we are more accepting of overweight and misclassify ourselves from a weight perspective. This may reduce our interest in losing weight. In a US survey 21% of overweight women and 46% of overweight men felt that their weight was “about right” (Burke 2010).

It seems that many obese people do not enjoy weight loss campaigns and prefer non-stigmatising interventions that are designed to improve lifestyles, rather than promotion of weight loss. In an Australian study, only one third of obese adults thought that media campaigns were effective in addressing obesity (Thomas 2010). They particularly dislike the negative presentation of overweight and the scare tactics used to get them to change.

Is there a solution?
It is easy to see fault in the repetitive weight loss campaigns that appear directionless. Even those that do their best to deliver useful health and weight information acknowledge the limitations and difficulties faced (Maitland). There may be some helpful changes that could change people’s behaviour:

1. Work with the food industry to improve the nutritional quality of food. That is already happening with Food and Health Dialogue, which has already made big steps in lowering the salt level of food. OK, less salt won’t influence weight but it is a good start in improving health.

2. Create exercise-friendly areas in the urban areas. Hats off to those municipalities that have extensive bike paths, parks and dog walking beaches.

3. Run advertising campaigns that demonstrate simple visual tips on increasing activity and eating better. These campaigns will be run by people who have been able to change their habits and are paid to be ambassadors for healthy habits.

One common touted solution is to tax certain foods. I have written before why I don’t think that will help. A more radical solution is to ban fast foods or limit their opening hours. A bit of idealism that won’t work in a free society.

For me, Yoda summed it all up in his advice to Luke Skywalker: “Try not. Do. Or do not. There is no try.” Don’t try to change a habit. You just change it. It’s hard, I know, that’s why almost no-one succeeds. Then, as another another famous person said: “Life wasn’t meant to be easy.”

What does it all mean?
In an affluent democracy with easy access to affordable food you will always have overweight folk. Long ago I predicted that overweight and obesity will stabilise at 75-80% of the population and the relatively lean will become a forgotten minority group who create weight loss campaigns. I was reminded of being in a minority when a large department store didn’t have a belt small enough for my 88 cm waist (34.5 in, and that ain’t skinny), and couldn’t sir just cut a few cms off the belt in the back shed? I’ll still continue to spread the message, yet resign myself to spreading it to an ever larger population.

Burke MA, Heiland FW, Nadler CM. From “overweight” to “about right”: evidence of a generational shift in body weight norms. Obesity 2010; 18: 1226-1234
Thomas SL, Lewis S, Hyde J, Castle D, Komesaroff P. “The solution needs to be complex”. Obese adults’ attitudes about the effectiveness of individual and population based interventions for obesity. BMC Public Health 2010; 10: 420
Maitland C, James N, Shilton T. Regional considerations for state-wide social marketing campaigns – some lessons learned. 11th National Rural Health Conference